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PostPosted: Sat Sep 18, 2021 6:38 pm 
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Location: South Benfleet, Essex
Several years ago, during the early 21st Century, when against the clock, I salvaged several items from a late-model Triumph Dolomite 1500 HL at the local fire station, one of the salvaged items was the engine’s cooling system radiator, which outwardly appeared identical to that of my 1974 Triumph Toledo 1300. Relatively recent comments on the forum, have indicated that the radiator for the 1500 engine (71 bhp), is longer than that for the 1300 engine (58 bhp), which is logical given the 22•4% greater maximum power output.

Different part numbers for the radiators and associated bottom hoses for the Triumph Dolomite 1300 & 1500/1500HL, listed in both my February 1995 and September 1998 issues of Rimmer Brothers’ Triumph Dolomite parts catalogue, confirmed that they are different:

Radiator (reconditioned): 1300 engine – 518954R and 1500 engine – 518955R

Radiator Top Hose: 1300 engine – GRH492 and 1500 engine – GRH492

Radiator Bottom Hose: 1300 engine – GRH493 and 1500 engine – GRH552

Noting that the salvaged Dolomite 1500 HL radiator appears to be in noticeably better condition than my original Toledo 1300 radiator, it seems sensible to substitute the higher cooling-capacity radiator, especially considering the gradually increasing ambient temperatures associated with global warming, and recalling the engine’s tendency to run hot in the past (temperature gauge pointer close to the red zone on my substituted early-model Triumph Dolomite 1850 temperature gauge), when driving at a sustained 65~70 mph on the M25 & M40 motorways in summer.

On Friday, 17th September 2021, I measured the dimensions of my original factory-fitted Triumph Toledo 1300 radiator and the Triumph Dolomite 1500 HL radiator, which are as follows:

Model / Dimensions . . . . . . . Total Height . . Matrix Height Total Width Matrix Width

Triumph Toledo 1300 . . . . . . 375 mm . . . . . 296 mm . . . . . 410 mm . . . . . 380 mm

Triumph Dolomite 1500 HL . . 450 mm . . . . . 372 mm . . . . . 410 mm . . . . . 380 mm

Difference in Dimensions . . . . 75 mm . . . . . . 0 mm . . . . . . . 76 mm . . . . . 0 mm

The total external widths of both the 1300 & 1500 radiators are identical at 410 mm, which is an important factor with regard to mounting the radiators into the car using the four factory-standard mounting brackets.

The total radiator-height and cooling-matrix-height of the Triumph Dolomite 1500HL radiator are both 75•5 ± 0• 5 mm (i.e. circa 3 inches) greater than those of the Triumph Toledo 1300 radiator, so the 1500 radiator has a 25•7% larger heat-exchange area than that of the 1300 radiator.

Given that 14-5/8 inches = 371•5 mm, an electric cooling fan of not more than 14 inches blade-diameter would seem to be the most appropriate for the 1500 radiator, whereas the 1300 radiator could only accommodate an electric cooling fan of not more than 11 inches blade-diameter, noting that 11-5/8 inches = 295•3 mm. An increase in blade diameter from 11 inches to 14 inches, corresponds to an increase in swept area of 62%.

The 25•7% increase in heat-exchange area, combined with a 62% increase in fan swept area, should provide a significant increase in cooling capacity, for high-speed motorway driving on hot summer days.

Another important matter which needs to be considered, is how the circa 75 mm longer radiator from a Triumph Dolomite 1500HL, is to be mounted into a Triumph Toledo 1300. Both the 1300 and 1500 radiators have diagonal pairs of threaded bolt-holes in the top and bottom of the radiator’s riveted steel side panels.

The important factors, are the positions of these pairs of bolt-holes relative to the bottom of the radiators’ header tank, and the vertical separation between the top and bottom pairs of bolt-holes.

. . . . . . . . . . . . . . . . . . . . . Vertical Bolt- . . . . . . . . . Diagonal Bolt- . . . . . . Header-Tank Bottom
Model / Dimensions . . . . . . . Hole Spacing . . . . . . . . . Hole Spacing . . . . . . . to Top Bolt-Hole

Triumph Toledo 1300 . . . . . . 190 mm = 7½ inches . . . 35 mm . . . . . . . . . . . 55 mm

Triumph Dolomite 1500 HL . . 254 mm = 10 inches . . . . 35 mm . . . . . . . . . . . 55 mm

Difference in Dimensions . . . . 64 mm = 2½ inches . . . . 0 mm . . . . . . . . . . . . 0 mm

Assuming the radiators’ upper mounting brackets for the Triumph Toledo 1300 and Triumph Dolomite 1500HL are identical, the alignment of both radiators’ header tanks, relative to the engine’s thermostat housing & top-hose connection spigot, should be the same. If this is the case, then these measurements indicate that either the radiators’ lower mounting brackets are different, or there is another pair of threaded bolt-holes, positioned 64 mm = 2½ inches lower, in the car’s front panel.

To the best of my recall, I also salvaged from the Triumph Dolomite 1500HL at the fire station, the upper & lower radiator mounting brackets, so I need to delve into my cache of bits & pieces to see how these might differ in any way, from those of my Triumph Toledo 1300.

If an electric-fan with 14 inch diameter fan blades is to be used instead of my present Kenlowe “Thermatic” fan (model No. 118/5 or 118/S) with 6-bladed, 10 inch diameter fan blades, the motor will probably have to be positioned in a 1½~2 inches lower position, so I shall need to investigate whether there would be sufficient clearance for the electric motor; although I would probably use a shorter alternative motor as I originally argued with Kenlowe in 1982; noting that they also produced "a 3 INCH DEEP MODEL for cars with restricted space".

My Kenlowe “Thermatic” fan measures a total of approximately 4¾ inches in length, from the face of the fan blades (the face closest to the front of the radiator core) to the external dimple in the end of the motor housing (incorporates the rotor-shaft bearing) closest to the front of the car. Had it been only 3 inches in total length, I would NOT have needed to make the 10 mm thick aluminium-alloy spacers for the radiator mounting brackets.

An increase in blade diameter from 10 inches to 13 inches or 14 inches, corresponds to increases in swept area of 69% and 96% respectively [n.b. (13/10)² = 1•69 and (14/10)² = 1•96], of which the latter results in almost a doubling in swept area.

Board index » The Triumph Dolomite Club » Dolomite-related [Start here!] » 40+ Years With A 1974 Triumph Toledo 1300 “HL Special”

viewtopic.php?f=4&t=29933

Engine-Cooling System Maintenance & Upgrades – Autumn 1980 onward

https://forum.triumphdolomite.co.uk/vie ... 97#p335497

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Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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PostPosted: Wed Sep 29, 2021 6:48 pm 
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Location: South Benfleet, Essex
I found the following reference from Steve Boitoult, posted more than 5¼ years ago, on Saturday, 7th May 2016 @ 5:45 pm:

Board index » The Triumph Dolomite Club » Restoration Projects » '72 Toledo 'Sonic' Shopping list created.

https://forum.triumphdolomite.co.uk/vie ... 74#p338774

« I have a fair used rad for a 1500HL which will fit the Toledo »

Hence, I deduce that I have reasonable expectations of completing this upgrade without too much difficulty! Hopefully, it won’t involve much more than sourcing a substitute bottom radiator hose (part No. GRH552) and a replacement electric fan with low-profile motor and 14 inch diameter fan blades. :D

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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PostPosted: Thu Sep 30, 2021 8:20 am 
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A couple of observations re you fan ideas.
Modern cars tend NOT to have a fan that is as big as the radiator. Instead the rely on proper shrouds so the fan actually pulls air through the entire core. Th shrouds often have flaps that swing open when the car is moving to enable plenty of airflow, but, typically when stationary, the running fan will create a partial vacuum within the shroud helping gravity keep the flaps shut.

So, my spitfire which uses a thin Golf radiator has a Spal 11" fan after the original Golf fan expired (only 30 years old). My advice is avoid kenlow etc and buy a quality fan from a company that publishes accurate specifications for their fans, T7 is a useful company to look up.

And anecdotally, bigger rads do not always help cooling. I know of a street rod using some HUGE american V8, mustang heads etc etc. After trying all sorts of radiators, the only one that worked was from a little old Ford Pop. But in general bigger should be better.

As to global warming, I don't think a 1degree change in average ambient temps will make any difference, What will is if the salvaged radiator is internally poor and has any tubes blocked. Quite possible if the car had a miserable few years with lack of maintenance. And impossible to check at home, though old radiator shops used to be able to test flow. And even remove a tank and poke tubes clear.

If cooling is a big issue, use pure water with no antifreeze but add some corrosion inhibitor. In teh winter use antifreeze, but only enough to cover the expected lowest temps in your region.

However, just about everybody survives without issues using normal practices.

_________________
Clive Senior
Brighton


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PostPosted: Sun Oct 03, 2021 5:13 pm 
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Although it’s been slightly more than 40 years since I studied the theory of fluid flow, heat transfer, heat exchangers, waste-heat recovery, total-energy systems, HVAC and several related topics (part of my two-year M.Sc. in Applied Energy Engineering at Cranfield Institute of Technology, during October 1979 to September 1981), I still recall the essence of those studies, despite not having been a practitioner in any of these fields for the past 29¼ years.

https://www.cranfield.ac.uk/

https://en.wikipedia.org/wiki/Cranfield_University

https://en.wikipedia.org/wiki/Cranfield ... 1969-1993)

I appreciate that heat exchange is not simply governed solely by the sizes of fans and heat exchangers, but the changes I mentioned are two things which I can implement easily and cheaply (the Dolomite 1500HL radiator effectively cost me nothing or next to nothing!), without making radical changes to the physical structure of the car. There are several factors which will influence the rate of heat dissipation from an internal combustion engine, of which I can readily identify the following:

a) Convective heat loss to air flowing over the engine block; dependent upon temperature differences and heat-transfer coefficients, which are a function of air-flow velocity and turbulence
b) Radiative heat loss to the surrounding engine compartment from the engine block; dependent upon surface emissivity and the differences in the fourth power of the surface absolute-temperatures (K = ºC + 273•15).
c) Fouling / scaling (e.g. lime-scale, rust or other oxidation) of the internal heat-exchange surfaces of the engine block and or radiator(i.e. cross-flow heat exchanger)
d) Mass-flow rate [kg/s] of the liquid coolant
e) Specific thermal capacity [kJ/(kg.ºC)] of the liquid coolant
f) Mass-flow rate [kg/s] of the gaseous coolant, which circumstances dictate will be the local atmospheric air
g) Specific thermal capacity [kJ/(kg.ºC)] of the gaseous coolant, which circumstances dictate will be the local atmospheric air; a variable that is dependent upon altitude and ambient temperature
h) Heat-exhange areas of both the engine’s internal liquid-coolant galleries and the radiator (i.e. cross-flow heat exchanger)
i) Turbulence in the heat-exchange regions of both the engine’s internal liquid-coolant galleries and the radiator.
j) Temperature difference between the in-flowing liquid coolant (i.e. water and/or anti-freeze or other liquid) and the gaseous coolant (i.e. local atmospheric air)

Mass-flow rate [kg/s] of the liquid coolant will be influenced by the effectiveness of the coolant-pump, viscosity of the coolant and any flow-restrictions in the thermostat housing (e.g. wax-thermostat that does not fully open), rust / scale build-up and/or surface roughness and/or blockages in the engine-block’s coolant-galleries, pipework or radiator tubes.

An engine’s liquid-cooling system and its cooling capacity at a given ambient air temperature & density, is limited by the maximum temperature at which the engine can reasonably operate without risking detonation and/or pre-ignition or reduced engine life for other reasons. The other major limitation is the maximum operational temperature of the cooling system, including the boiling point of the coolant, which is dependent upon the pressure-rating of the radiator-cap or expansion-tank-cap as applicable and the nature of the coolant liquid.

The boiling point of all liquids increases with the pressure of gas (typically air) above the free-surface of the liquid; of which the domestic-kitchen pressure cooker and pressurised automotive cooling systems are common examples. Where the liquid is a mixture of substances (solvent & solute | e.g. water & antifreeze), the boiling point of the mixture is elevated compared to that of the pure liquids. They are also subject to freezing-point depression, but that’s another story related to the primary reason why antifreeze is used.

The greater the temperature difference between the “hot” liquid-coolant (e.g. water or water & antifreeze mixture) and the “cold” gaseous-coolant (i.e. ambient air), the greater the potential cooling capacity of the radiator; all other factors like air-density being unchanged.

Quote:
If cooling is a big issue, use pure water with no antifreeze but add some corrosion inhibitor. In the winter use antifreeze, but only enough to cover the expected lowest temps in your region.

You have already mentioned specific thermal capacity [J/(kg.ºC)] of the liquid coolant in a roundabout way, when you suggested using pure water and corrosion inhibitors in summer, and pure water with the minimum proportion of antifreeze in winter; although cooling capacity in winter has never been a problem, even using a coolant mixture with 30% antifreeze by volume (complete protection down to minus-16 ºC). Ethylene glycol based antifreeze, has a specific thermal capacity which is about two thirds that of water.

I live in a “hard-water” area where build-up of lime-scale is a perpetual problem, so I have always been wary of using “tap-water” in the cars’ coolant systems; preferring to use distilled water (a free perk from the laboratory where I worked) rain water or melt-water from defrosting the freezer.

Whenever I routinely replaced the engine coolant every few years, before winter, I commonly flushed the cooling system by running the engine on water & de-scaler (e.g. Furnox de-scaler used for flushing multi-metal domestic central-heating systems) for a few days.

It’s been a while since I last removed and checked the 88 ºC “winter” wax-thermostat (part No. GTS106), so this is something I shall do, before I put the car back on the road after its long hibernation. If appropriate, I shall replace the wax-thermostat with one of the same or lower temperature rating, such as the standard 82 ºC “summer” wax-thermostat (part No. GTS104).

Quote:
As to global warming, I don't think a 1degree change in average ambient temps will make any difference, What will is if the salvaged radiator is internally poor and has any tubes blocked. Quite possible if the car had a miserable few years with lack of maintenance. And impossible to check at home, though old radiator shops used to be able to test flow. And even remove a tank and poke tubes clear.

It’s not the Global changes in average ambient air temperatures, of just a few degrees Celcius, that are so significant in this regard, but the relatively short-duration, extreme events, such as the major high-temperature heat waves that were experienced in southern Europe and western Canada & USA earlier this year, and which are becoming more common in Great Britain. Such high temperatures in British Columbia, where they suffered major forest fires and the destruction of one town were unprecedented, and Sicily in southern Europe also experienced uncomfortably high temperatures, peaking at 48•8 ºC. In such extreme high-temperature conditions, a vehicle with an air-cooled engine would probably be more appropriate!

Quote:
Modern cars tend NOT to have a fan that is as big as the radiator. Instead they rely on proper shrouds so the fan actually pulls air through the entire core. The shrouds often have flaps that swing open when the car is moving to enable plenty of airflow, but, typically when stationary, the running fan will create a partial vacuum within the shroud helping gravity keep the flaps shut. So, my spitfire which uses a thin Golf radiator has a Spal 11" fan after the original Golf fan expired (only 30 years old).

Apart from once driving my father’s 2004 Seat Leon Cupra 20V Turbo, the 1¼ miles from the local MOT testing station, I have absolutely no experience of ultra-modern & modern cars, apart from my father’s former 1986 Ford Sierra XR4x4; all other vehicles I have driven, being from the 1970s & 1980s. The 1974 Triumph Toledo 1300, which I first drove in May 1975, is the most modern vehicle I have owned and am likely to own!

The configuration of the Triumph Toledo’s & Dolomite’s front-end, with large central barrier (between the left-hand & right-hand radiator-grilles cum headlamp trims) to air flow through the radiator, is likely to hamper engine cooling, but whether it would be practical to duct additional air flow through the radiator matrix is questionable, and it’s even more unlikely that one can direct air-flow through the shaded central band of the radiator. This is probably why Steve Boitoult’s Vauxhall Carlton engined, 1973 Triumph Toledo “Carledo”, has additional large swaged holes in the lower front valance and a relocated front registration-number plate.

Board index » The Triumph Dolomite Club » Dolomite-related [Start here!] » A question for 1300 & 1500cc owners -Does your car have deflector boards fitted

https://forum.triumphdolomite.co.uk/vie ... =4&t=36784

It’s questionable whether there would be sufficient space for a suitably-engineered, contoured fan shroud, either in front or behind a standard Triumph Toledo 1300/1500 or Dolomite 1300/1500 radiator, mounted in the factory-standard location; even with the belt-driven mechanical fan removed. Even if it were possible to implement (possibly including internal vanes), there is no guarantee that it would result in uniform air-flow through all parts of the radiator matrix; owing to the large central air-flow obstruction in front of the radiator.

Quote:
My advice is avoid kenlow etc and buy a quality fan from a company that publishes accurate specifications for their fans, T7 is a useful company to look up.

Manufacturers tend to specify fan-characteristics under free-air conditions, with no regard given to air-flow restrictions, either on the suction or discharge sides of the fan, so it’s difficult to predict how fans would perform in any given radiator-cooling application. Ideally one would experimentally investigate their performance using appropriate test rigs and instrumentation (something I did with HVAC systems at Haden Carrier’s Group Central Laboratories), but sadly I no longer have access to such facilities!

Whatever else happens, one needs to avoid stalling the fan blades (an aerodynamic phenomenon also experienced by aircraft wings), so from that perspective it’s better to operate a fan in blowing mode rather than sucking mode, especially if there would be a significant air-flow restriction upstream of the fan, which might cause a major reduction in upstream static pressure.

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


Last edited by naskeet on Wed Oct 06, 2021 7:22 pm, edited 2 times in total.

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PostPosted: Mon Oct 04, 2021 1:00 am 
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Location: Highley, Shropshire
Quote:

The configuration of the Triumph Toledo’s & Dolomite’s front-end, with large central barrier (between the left-hand & right-hand radiator-grilles cum headlamp trims) to air flow through the radiator, is likely to hamper engine cooling, but whether it would be practical to duct additional air flow through the radiator matrix is questionable, and it’s even more unlikely that one can direct air-flow through the shaded central band of the radiator. This is probably why Steve Boitoult’s Vauxhall Carlton engined, 1973 Triumph Toledo “Carledo”, has additional large swaged holes in the lower front valance and a relocated front registration-number plate.
Too right it is!

I've NOT studied fluid dynamics or anything much else in the academic sense. I'm much more of a rule of thumb, "suck it and see" kind of engineer.

The Carledo in it's present form, is, as is normal for this sort of car, the result of continuous development over a number of years.

As originally built, way back in 2010, it ran the Carlton's massive 16" dia engine driven viscous coupled fan (but unshrouded unlike the Carlton app) and initially, the stock Toledo rad! This was just a stopgap to get it driveable. Surprisingly, the rad actually coped with normal driving but couldn't handle even brief stops at road works traffic lights etc. Largely due, I think to the Carlton's 92 degree thermostat not leaving enough margin of error, abetted by the lack of shrouding.

The stock rad was quickly replaced with a much larger but thinner one from a scrapyard 98 MY non-turbo Saab 9-3 and a rather large single hole in the front valance to improve airflow. This improved matters considerably but was still not sufficient to keep it cool in traffic. It took much longer (probably 15 mins) to become uncomfortably hot in summer traffic jams, but it always happened. A temporary expedient I adopted was to switch it off whenever I wasn't actually moving.

I had acquired the 9-3's electric fan and shroud along with the rad, but due to it's considerable bulk and a production quirk where the fan sender on the Saab was in the engine and the Carlton didn't have one, I had nowhere to put a sender for it. So I didn't fit it.

I paid the price for my folly at the 2014 Retro rides gathering at Prescott hill climb, queueing for entrance for over an hour, I let it get just a tad too hot and blew the head gasket. It didn't stop me doing several quick runs up the hill or driving it home afterwards, but something needed to be done!

After replacing the head gasket, along with a slightly larger than strictly necessary head skim, I finally ditched the engine driven fan and installed, with minimal cutting, the fan and shroud from the Saab, initally, with just a relay and a manual switch, later with a top hose mounted aftermarket thermostatic sender. This cured the problem entirely. Though the fan is still fairly large, at 13" diameter, it's not as big as the engine driven one was, so I can only conclude that the shrouding is entirely responsible for the improvement.

The fan is fortunately fitted offset from centre so almost entirely in line with the N/S grille (and the hottest side of the radiator) and the shroud has those "flaps" that Clive mentioned on the O/S.

A final postscript to the story, I removed the manual fan switch when I fitted the thermostatic one, which turned out to be a mistake. The fan rarely deployed, especially during the winter months and one rainy Friday in heavy Birmingham traffic the thermostatic switch failed (or had already failed and I hadn't noticed) and I cooked the engine quite thoroughly before I could find a spot to pull over and short the switch wiring temporarily into permanent operation. Though not to the point of HGF this time. Embarrassingly for me, our own Alun (xvivalve) Nicholas was on board at the time! Needless to say, I replaced the manual over-ride switch tout-de-suite!

The lessons learned from this have all been applied to the Dolomega. THAT car's cooling system works perfectly, straight from the box!

A word about airflow and possible stalling fans. There is a design flaw in nearly every water cooled car that trumps every best effort by manufacturers (or US) at providing good airflow through the engine bay. That being the fact that there is a vertical bulkhead behind the engine that, along with closed bonnet above and solid flitches to either side, effectively acts like a cul de sac, stopping the airflow through the engine bay dead in it's tracks. In our configuration with the rad at the front of the car, it's almost inevitable. The ONLY exceptions I can think of are the BMC mini, 1100, 1300, Maxi and 1800 where air comes into the engine bay through the grille, hits the bulkhead and o/s flitch and bonnet (and engine) and gets an exit by passing through the rad and out though a convenient vent in the N/S flitch. This is a LOT more efficient, the air is not heated by the rad until it's almost out of the bay and the engine has COLD air direct from the grille passing over it rather than hot air already heated by the radiator, inspired work from Issigonis. This system actually uses the pressure build up in the engine bay to it's advantage, because of this, these cars need relatively smaller radiators.

Short of relocating the rad in a similar fashion, which might be very tricky, I recommend a decent batch of louvres at the rear of the bonnet, it gives all that pressure somewhere to go whilst driving and allows the built up hot air under the bonnet to dissipate harmlessly upwards when stationary in traffic. A couple of beneficial side effect of louvres are that the carburettor(s) stay cooler, less chance of fuel vaporisation with ethanol added fuels and the windscreen clears quicker on icy mornings from hot air being pushed up through the louvres onto the screen when driving.

Steve

_________________
'73 2 door Toledo with Vauxhall Carlton 2.0 8v engine (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine (The Dolomega)
'72 Triumph 1500FWD in Slate Grey, Now with RWD and Carledo powertrain!

Maverick Triumph, Servicing, Repairs, Electrical, Recomissioning, MOT prep, Trackerjack brake fitting service.
Apprentice served Triumph Specialist for 50 years. PM for more info or quotes.


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PostPosted: Wed Oct 06, 2021 11:56 pm 
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Joined: Wed Apr 14, 2010 1:40 pm
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Location: rotherham south yorkshire
The bottom short radiator brackets are different on a Toledo , they angle up towards the radiator.

_________________
1973 yellow Sprint L reg
1979 1500 SE T reg
1979 1500 SE V reg
1980 vermillion 1500hl W reg
1975 green 1500tc auto P reg
1971 wedgewood blue 2000 auto mk2 J reg
1979 Sandglow 1500HL auto V reg
1972 valencia blue Toledo 2 dr K reg
1973 Brown Toledo 2 dr L reg
1973 Green Toledo 2 dr L reg
1977 white Datsun 100a f2 S reg
1983 White Toyota Tercel 4x4
1987 Brown Toyota Tercel 4x4
1988 Blue Toyota Tercel 4x4
1999 Toyota Corolla vvti est
2005 Ford ranger thunder XLT
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PostPosted: Sat Oct 09, 2021 6:53 pm 
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Joined: Tue May 06, 2014 4:38 pm
Posts: 535
Location: South Benfleet, Essex
Radiator Cooling Fans

Quote:
My advice is avoid kenlow etc and buy a quality fan from a company that publishes accurate specifications for their fans, T7 is a useful company to look up.

On Friday, 29th August 1991, whilst travelling home to Canvey Island, Essex for the weekend, from RMCS – Royal Military College of Science, on the border of Oxfordshire & Wiltshire, the Kenlowe electric cooling fan ceased to function. The fan warning light illuminated when activated by either the fan's thermostatic switch or the manual-override switch, but there was no perceptible whirring-fan noise, that would have been easily audible to me, even at motorway driving speeds.

By driving the car at reduced speed and turning on the car's heater with the booster-fan at maximum, I was able to avoid the engine overheating, but the temperature gauge reading remained high. Had this been unsuccessful, I would have stopped en route, to refit the belt-driven cooling fan, which I kept in the boot as a back-up spare, along with various other items.

When I got home and investigated the problem over the weekend, I discovered that the problem lay with the fan-motor, whose carbon brushes had substantially worn down, but I did not have any spares readily to hand. Consequently, on Sunday, 11th August 1991, at a mileage of circa 85,367, I temporarily removed the electric fan and refitted the belt-driven fan, so that I could use the car to return to RMCS later that evening.

In several ways, the Kenlowe fan motor appeared similar to the Smiths motor associated with the Toledo's factory-fitted booster-fan for the car’s heating & ventilation system. When I stripped down the motor to inspect the carbon brushes, I discovered that the whole brush-holder assembly, including the brown composite (Tufnell I think) base-board, to which the brush-holders are attached, was identical to that of the Smiths booster-fan. A few weeks later I was able salvage one of these from a Triumph Toledo and/or Dolomite at one of the local car breakers' yards. This enabled me to repair and refit the Kenlowe fan motor on Saturday, 31st August 1991, at a mileage of circa 85,918•5.

Noting that I had retro-fitted the Kenlowe fan to the car at a mileage of circa 24,500 and later suffered fan-motor failure at a mileage of circa 85,367, indicates that the Kenlowe fan installation had failed after slightly more than 60,000 miles of driving; suggesting that it would probably be wise to acquire a few more spare Smiths brush-holder assemblies, for future replacement during the life of the car, which I did at a later date when they became available.

Quote:
Manufacturers tend to specify fan-characteristics under free-air conditions, with no regard given to air-flow restrictions, either on the suction or discharge sides of the fan, so it’s difficult to predict how fans would perform in any given radiator-cooling application. Ideally one would experimentally investigate their performance using appropriate test rigs and instrumentation (something I did with HVAC systems at Haden Carrier’s Group Central Laboratories), but sadly I no longer have access to such facilities!

As a sponsored postgraduate engineering student at CIT – Cranfield during the early-1980s, I spent my vacations working in the Building Services Section, of Haden Carrier’s Group Central Laboratories, where I investigated the performance of a variety of appliances and sub-systems for heating, ventilation and air-conditioning. I was told of a book entitled “The Fan” [of which I have still yet to find a copy! :cry: ], which despite its then age, was said to still be regarded as the definitive work on the subject of fan design and performance.

Whilst I was teaching during 1992/93, in the Department of Engineering & Motor Vehicle Studies, at SEECAT – South East Essex College of Arts & Technology, I salvaged the following ancient tome, which was being disposed of, during a major clear-out of old reference books:

John L. Alden, MASME, “Design of Industrial Exhaust Systems For Dust and Fume Removal”, The Industrial Press, 2nd Edition, 1948

Chaper X – Axial Flow Fans, on Pages 199~210, examines the characteristics of axial-flow fans used in a variety of situations, some of which might be considered to be similar in principle to the use of axial-flow fans for automotive radiator cooling, whether it be like the Toledo’s & Dolomite’s factory-fitted, belt-driven fan or the after-market electric fans which are commonly retro-fitted to classic cars, in a bid to improve cooling efficiency in slow-moving congested traffic and avoid power-wasting over-cooling at other times.

The chapter examines three basic varieties of axial-flow fan, described as (a) propeller fan, (b) tubeaxial fan, and (c) vaneaxial fan, of which the first best describes the type of fan used in automotive radiator cooling applications. The description on Pages 199 & 200 reads [including my explanatory notes, prefixed by the abbreviation n.b.] as follows:

Propeller Fan

« The propeller fan consists of two or more blades mounted on a central shaft and revolving within a narrow mounting ring. Figure 102 is a schematic illustration of a typical propeller fan. These fans are usually designed to operate in the range from free delivery to about ½-inch water [n.b. inches water-gauge]. When driven at blade-tip speeds of from 12,000 to 16,000 f.p.m. [n.b. feet per minute] they are capable of operating against pressures of up to 1½ inches but at sacrifice of capacity and efficiency. Moreover, the noise level may become objectionable at these speeds. »

« Because of its pressure limitations, the propeller fan finds its principal application in general room ventilation when mounted in a side wall or roof monitor and discharging directly to the atmosphere. Frequently the arrangement of spray booths or welding booths is such that they can be exhausted to the open air through short and direct piping. »

« When this is possible the propeller fan may be the logical choice. Although there are few suitable applications for this type of fan where more than the simplest duct work is involved, it is without doubt the cheapest fan both in first cost and in power consumption when static pressure can be kept below ½-inch of water. »


Although probably still in common usage within the USA’s HVAC community, static and dynamic / velocity pressures [n.b. static pressure + dynamic / velocity pressure = stagnation / total pressure] expressed in inches of water or inches water-gauge, have largely been super ceded by kPa – kiloPascals.

A pressure of 1 Bar = 1 Atmosphere = 100 kPa, is the measure of standard atmospheric pressure at sea level and will support a column of water about 32 feet high, in the form of a Fortin barometer.

Recalling one's secondary-school science lessons, practical Fortin barometers for measuring atmospheric pressure in the laboratory, contain liquid-mercury rather than water, because mercury has a density (kg/m³) which is 13•6 times greater than that of water, so the approximately 760 mm high column of liquid mercury in the barometer, is 13•6 times shorter than a column of water would be. It was Toricelli, an Italian scientist, who first devised a practical, portable barometer using liquid-mercury, which led to his discovery that atmospheric pressure decreased with altitude.

To put this in perspective, the pressure (Pa = N/m²) exerted by a column of liquid, is equal to the product (i.e. multiplication) of liquid density (kg/m³), gravitational acceleration (9•81 m/s²) and liquid-column height (m). Given that the density of water is 1000 kg/m³ = 1 tonne/ m³ and 1 inch = 25•4 mm = 0•0254 m, then 1 inch water-gauge = 249 Pa = 0•249 kPa.

Hence in round numbers, ½-inch water-gauge = 125 Pa = 0•125 kPa and 1½-inch water-gauge = 375 Pa = 0•375 kPa

Recalling further that 1 Bar = 100 kPa = 14•7 psi, then 1-inch water-gauge = 0•0366 psi

These are small air pressures, for which one needs to use a micro-manometer, of which an incline gauge filled with a relatively low-density liquid like paraffin, is one example I commonly used in my HVAC work at Haden Carrier.

Pages 207, 208 & 209 of the book reads [including my explanatory notes, prefixed by the abbreviation n.b.] as follows:

Fan Characteristics

« The characteristic curves of Figure 110 are typical of axial flow fans. The pressure-volume curve shows how these relationships change as flow decreases from the condition of free delivery to that of no delivery. Starting at the free delivery point (the base line), the pressure rises as the volume decreases until what is known as the stalling point is reached. This is the point at which the flow lines begin to depart from the inlet side of the blade surface and is the region in which eddies and vortices begin to form. It corresponds to the stalling or “burbling” point of an aircraft wing whose angle of attack has been increased until a loss of lift occurs. »

« As might be expected, the region between the stalling point and the no-delivery point constitutes an undesirable operating zone. The stalling dip is a symptom of instability and the sudden rise of the noise level which accompanies it is an infallible sign of serious flow disturbance. It is evident the system characteristics must be matched with the fan characteristics lying to the right of the stalling point. It is this feature of axial flow fans which makes their application to systems of fluctuating characteristics somewhat more critical than the application of centrifugal fans [n.b. the Triumph Toledo’s & Dolomite’s heater-booster fan is a centrifugal fan]. »

« In Figure 111 are plotted the pressure-volume curves of four axial flow fans of different types [ n.b. four types in order of increasing static-pressure capability: (i) propeller fan, (ii) tubeaxial fan, (iii) 1-stage vaneaxial fan, and (iv) 2-stage vaneaxial fan] but of the same diameter and speed. The four performance curves are of the same basic shape although the stalling dip becomes more pronounced in the higher pressure fans. The parabolic lines representing system characteristics, intersect the pressure-volume lines of each fan at the design point or point of highest efficiency. »


This description of axial-flow fan operating characteristics, might not be very intelligible or sufficiently detailed for one to properly select an appropriate fan with any confidence, but it should demonstrate that there is a great deal more to fan selection, than simply comparing the maximum air-flow delivery rates (i.e. free delivery, volumetric flow rates) of any given fan, and that one ideally needs to know something about their pressure-volume characteristics and the static & dynamic pressure conditions in which they will be required to operate.

https://www.tcf.com/wp-content/uploads/ ... E-2000.pdf

https://pdhonline.com/courses/m213/m213content.pdf

https://www.axair-fans.co.uk/news/under ... -fan-laws/

https://www.axair-fans.co.uk/all-techni ... an-curves/

https://www.scy-fan.com/what-is-the-fan ... ics-curve/

I really must try to get my hands on a copy of that book entitled “The Fan” or a more up-to-date equivalent! :cry:

T7 Design in or near Exeter, have quite an extensive selection of nice looking radiator cooling fans, but they also seem rather expensive, not including the mounting hardware and other components.

T7 Design Ltd, Unit 4, Clyst Units, Cofton Road, Marsh Barton, Exeter, EX2 8QW, UK

Tel. +44 (0) 1392 423 390

Fax. +44 (0) 7595 975 777

E-mail: info@t7design.co.uk

https://www.t7design.co.uk/

Quote:
Manufacturers tend to specify fan-characteristics under free-air conditions, with no regard given to air-flow restrictions, either on the suction or discharge sides of the fan, so it’s difficult to predict how fans would perform in any given radiator-cooling application. Ideally one would experimentally investigate their performance using appropriate test rigs and instrumentation (something I did with HVAC systems at Haden Carrier’s Group Central Laboratories), but sadly I no longer have access to such facilities!

In the technical specifications for the SPAL fans, T7 Design quote maximum air-flow rates, which as I had surmised, fundamentally refers to the air-flow rates that are obtainable under free-air conditions.

https://www.t7design.co.uk/products/rad ... -fans.html

SPAL Radiator Fan - 13.8" (350mm) Push VA08-AP71/LL-53S | £168.00 = £140.00 + VAT

https://www.t7design.co.uk/spal-radiato ... l-53s.html

SPAL Radiator Fan - 13.0" (330mm) Pull VA13-AP70/LL-63A 1718cfm | £129.00 = £107.50 + VAT

https://www.t7design.co.uk/spal-radiato ... l-63a.html

SPAL Radiator Fan - 12" (305mm) Push VA10-AP70LL-61S 1292cfm | £120.00 = £100.00 + VAT

https://www.t7design.co.uk/spal-radiato ... l-61s.html

Surprisingly, whilst researching SPAL radiator cooling fans, I also stumbled upon electrical engine-coolant pre-heaters made by Calix, which also featured on the website of T7 Design in or near Exeter.

https://www.t7design.co.uk/

https://www.t7design.co.uk/engine-heating.html

Quote:
A word about airflow and possible stalling fans. There is a design flaw in nearly every water cooled car that trumps every best effort by manufacturers (or US) at providing good airflow through the engine bay. That being the fact that there is a vertical bulkhead behind the engine that, along with closed bonnet above and solid flitches to either side, effectively acts like a cul de sac, stopping the airflow through the engine bay dead in it's tracks. In our configuration with the rad at the front of the car, it's almost inevitable.

The ONLY exceptions I can think of are the BMC mini, 1100, 1300, Maxi and 1800 where air comes into the engine bay through the grille, hits the bulkhead and o/s flitch and bonnet (and engine) and gets an exit by passing through the rad and out though a convenient vent in the N/S flitch. This is a LOT more efficient, the air is not heated by the rad until it's almost out of the bay and the engine has COLD air direct from the grille passing over it rather than hot air already heated by the radiator, inspired work from Issigonis. This system actually uses the pressure build up in the engine bay to it's advantage, because of this, these cars need relatively smaller radiators.

Short of relocating the rad in a similar fashion, which might be very tricky, I recommend a decent batch of louvres at the rear of the bonnet, it gives all that pressure somewhere to go whilst driving and allows the built up hot air under the bonnet to dissipate harmlessly upwards when stationary in traffic. A couple of beneficial side effect of louvres are that the carburettor(s) stay cooler, less chance of fuel vaporisation with ethanol added fuels and the windscreen clears quicker on icy mornings from hot air being pushed up through the louvres onto the screen when driving.

Steve

I suspect that post-vintage, RWD car designers / stylists, hoped that warm air entering the engine bay, would exit via the transmission tunnel at the rear of the engine bay, beneath the bulkhead.

I recall that many vintage cars, with two-piece, central, longitudinally-hinged bonnets, had louvred slots in the vertical sides of said bonnets, which I surmise served the purpose you describe. I am told that at least some relatively-modern, high-performance cars, also feature such louvres, in the horizontal, front-hinged or rear-hinged bonnets.

Not being a sheet-metal worker by either training or experience, I am unsure how one would cut & shape, either internal or external louvres, in an existing Toledo or Dolomite bonnet, but I suspect there might be a special tool designed for the purpose. One would need to locate these louvres, so that rain-water did not drain onto any vital electrical or ignition-system components.

It would be interesting to somehow measure, the air-flow rate into the engine bay of a Toledo or Dolomite, before and after the addition of louvres! I can think of various ways in which this might be done, if one had access to the appropriate facilities, which ideally would include an automotive wind-tunnel!

Quote:
The bottom short radiator brackets are different on a Toledo , they angle up towards the radiator.

When you say that the Toledo’s bottom radiator-brackets are different, do you mean they are different from those of the Dolomite 1300 or the Dolomite 1500 or both?

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


Top
   
PostPosted: Sun Oct 10, 2021 8:59 pm 
Offline
TDC Member

Joined: Wed Apr 14, 2010 1:40 pm
Posts: 436
Location: rotherham south yorkshire
Quote:
Radiator Cooling Fans

Quote:
My advice is avoid kenlow etc and buy a quality fan from a company that publishes accurate specifications for their fans, T7 is a useful company to look up.

On Friday, 29th August 1991, whilst travelling home to Canvey Island, Essex for the weekend, from RMCS – Royal Military College of Science, on the border of Oxfordshire & Wiltshire, the Kenlowe electric cooling fan ceased to function. The fan warning light illuminated when activated by either the fan's thermostatic switch or the manual-override switch, but there was no perceptible whirring-fan noise, that would have been easily audible to me, even at motorway driving speeds.

By driving the car at reduced speed and turning on the car's heater with the booster-fan at maximum, I was able to avoid the engine overheating, but the temperature gauge reading remained high. Had this been unsuccessful, I would have stopped en route, to refit the belt-driven cooling fan, which I kept in the boot as a back-up spare, along with various other items.

When I got home and investigated the problem over the weekend, I discovered that the problem lay with the fan-motor, whose carbon brushes had substantially worn down, but I did not have any spares readily to hand. Consequently, on Sunday, 11th August 1991, at a mileage of circa 85,367, I temporarily removed the electric fan and refitted the belt-driven fan, so that I could use the car to return to RMCS later that evening.

In several ways, the Kenlowe fan motor appeared similar to the Smiths motor associated with the Toledo's factory-fitted booster-fan for the car’s heating & ventilation system. When I stripped down the motor to inspect the carbon brushes, I discovered that the whole brush-holder assembly, including the brown composite (Tufnell I think) base-board, to which the brush-holders are attached, was identical to that of the Smiths booster-fan. A few weeks later I was able salvage one of these from a Triumph Toledo and/or Dolomite at one of the local car breakers' yards. This enabled me to repair and refit the Kenlowe fan motor on Saturday, 31st August 1991, at a mileage of circa 85,918•5.

Noting that I had retro-fitted the Kenlowe fan to the car at a mileage of circa 24,500 and later suffered fan-motor failure at a mileage of circa 85,367, indicates that the Kenlowe fan installation had failed after slightly more than 60,000 miles of driving; suggesting that it would probably be wise to acquire a few more spare Smiths brush-holder assemblies, for future replacement during the life of the car, which I did at a later date when they became available.

Quote:
Manufacturers tend to specify fan-characteristics under free-air conditions, with no regard given to air-flow restrictions, either on the suction or discharge sides of the fan, so it’s difficult to predict how fans would perform in any given radiator-cooling application. Ideally one would experimentally investigate their performance using appropriate test rigs and instrumentation (something I did with HVAC systems at Haden Carrier’s Group Central Laboratories), but sadly I no longer have access to such facilities!

As a sponsored postgraduate engineering student at CIT – Cranfield during the early-1980s, I spent my vacations working in the Building Services Section, of Haden Carrier’s Group Central Laboratories, where I investigated the performance of a variety of appliances and sub-systems for heating, ventilation and air-conditioning. I was told of a book entitled “The Fan” [of which I have still yet to find a copy! :cry: ], which despite its then age, was said to still be regarded as the definitive work on the subject of fan design and performance.

Whilst I was teaching during 1992/93, in the Department of Engineering & Motor Vehicle Studies, at SEECAT – South East Essex College of Arts & Technology, I salvaged the following ancient tome, which was being disposed of, during a major clear-out of old reference books:

John L. Alden, MASME, “Design of Industrial Exhaust Systems For Dust and Fume Removal”, The Industrial Press, 2nd Edition, 1948

Chaper X – Axial Flow Fans, on Pages 199~210, examines the characteristics of axial-flow fans used in a variety of situations, some of which might be considered to be similar in principle to the use of axial-flow fans for automotive radiator cooling, whether it be like the Toledo’s & Dolomite’s factory-fitted, belt-driven fan or the after-market electric fans which are commonly retro-fitted to classic cars, in a bid to improve cooling efficiency in slow-moving congested traffic and avoid power-wasting over-cooling at other times.

The chapter examines three basic varieties of axial-flow fan, described as (a) propeller fan, (b) tubeaxial fan, and (c) vaneaxial fan, of which the first best describes the type of fan used in automotive radiator cooling applications. The description on Pages 199 & 200 reads [including my explanatory notes, prefixed by the abbreviation n.b.] as follows:

Propeller Fan

« The propeller fan consists of two or more blades mounted on a central shaft and revolving within a narrow mounting ring. Figure 102 is a schematic illustration of a typical propeller fan. These fans are usually designed to operate in the range from free delivery to about ½-inch water [n.b. inches water-gauge]. When driven at blade-tip speeds of from 12,000 to 16,000 f.p.m. [n.b. feet per minute] they are capable of operating against pressures of up to 1½ inches but at sacrifice of capacity and efficiency. Moreover, the noise level may become objectionable at these speeds. »

« Because of its pressure limitations, the propeller fan finds its principal application in general room ventilation when mounted in a side wall or roof monitor and discharging directly to the atmosphere. Frequently the arrangement of spray booths or welding booths is such that they can be exhausted to the open air through short and direct piping. »

« When this is possible the propeller fan may be the logical choice. Although there are few suitable applications for this type of fan where more than the simplest duct work is involved, it is without doubt the cheapest fan both in first cost and in power consumption when static pressure can be kept below ½-inch of water. »


Although probably still in common usage within the USA’s HVAC community, static and dynamic / velocity pressures [n.b. static pressure + dynamic / velocity pressure = stagnation / total pressure] expressed in inches of water or inches water-gauge, have largely been super ceded by kPa – kiloPascals.

A pressure of 1 Bar = 1 Atmosphere = 100 kPa, is the measure of standard atmospheric pressure at sea level and will support a column of water about 32 feet high, in the form of a Fortin barometer.

Recalling one's secondary-school science lessons, practical Fortin barometers for measuring atmospheric pressure in the laboratory, contain liquid-mercury rather than water, because mercury has a density (kg/m³) which is 13•6 times greater than that of water, so the approximately 760 mm high column of liquid mercury in the barometer, is 13•6 times shorter than a column of water would be. It was Toricelli, an Italian scientist, who first devised a practical, portable barometer using liquid-mercury, which led to his discovery that atmospheric pressure decreased with altitude.

To put this in perspective, the pressure (Pa = N/m²) exerted by a column of liquid, is equal to the product (i.e. multiplication) of liquid density (kg/m³), gravitational acceleration (9•81 m/s²) and liquid-column height (m). Given that the density of water is 1000 kg/m³ = 1 tonne/ m³ and 1 inch = 25•4 mm = 0•0254 m, then 1 inch water-gauge = 249 Pa = 0•249 kPa.

Hence in round numbers, ½-inch water-gauge = 125 Pa = 0•125 kPa and 1½-inch water-gauge = 375 Pa = 0•375 kPa

Recalling further that 1 Bar = 100 kPa = 14•7 psi, then 1-inch water-gauge = 0•0366 psi

These are small air pressures, for which one needs to use a micro-manometer, of which an incline gauge filled with a relatively low-density liquid like paraffin, is one example I commonly used in my HVAC work at Haden Carrier.

Pages 207, 208 & 209 of the book reads [including my explanatory notes, prefixed by the abbreviation n.b.] as follows:

Fan Characteristics

« The characteristic curves of Figure 110 are typical of axial flow fans. The pressure-volume curve shows how these relationships change as flow decreases from the condition of free delivery to that of no delivery. Starting at the free delivery point (the base line), the pressure rises as the volume decreases until what is known as the stalling point is reached. This is the point at which the flow lines begin to depart from the inlet side of the blade surface and is the region in which eddies and vortices begin to form. It corresponds to the stalling or “burbling” point of an aircraft wing whose angle of attack has been increased until a loss of lift occurs. »

« As might be expected, the region between the stalling point and the no-delivery point constitutes an undesirable operating zone. The stalling dip is a symptom of instability and the sudden rise of the noise level which accompanies it is an infallible sign of serious flow disturbance. It is evident the system characteristics must be matched with the fan characteristics lying to the right of the stalling point. It is this feature of axial flow fans which makes their application to systems of fluctuating characteristics somewhat more critical than the application of centrifugal fans [n.b. the Triumph Toledo’s & Dolomite’s heater-booster fan is a centrifugal fan]. »

« In Figure 111 are plotted the pressure-volume curves of four axial flow fans of different types [ n.b. four types in order of increasing static-pressure capability: (i) propeller fan, (ii) tubeaxial fan, (iii) 1-stage vaneaxial fan, and (iv) 2-stage vaneaxial fan] but of the same diameter and speed. The four performance curves are of the same basic shape although the stalling dip becomes more pronounced in the higher pressure fans. The parabolic lines representing system characteristics, intersect the pressure-volume lines of each fan at the design point or point of highest efficiency. »


This description of axial-flow fan operating characteristics, might not be very intelligible or sufficiently detailed for one to properly select an appropriate fan with any confidence, but it should demonstrate that there is a great deal more to fan selection, than simply comparing the maximum air-flow delivery rates (i.e. free delivery, volumetric flow rates) of any given fan, and that one ideally needs to know something about their pressure-volume characteristics and the static & dynamic pressure conditions in which they will be required to operate.

https://www.tcf.com/wp-content/uploads/ ... E-2000.pdf

https://pdhonline.com/courses/m213/m213content.pdf

https://www.axair-fans.co.uk/news/under ... -fan-laws/

https://www.axair-fans.co.uk/all-techni ... an-curves/

https://www.scy-fan.com/what-is-the-fan ... ics-curve/

I really must try to get my hands on a copy of that book entitled “The Fan” or a more up-to-date equivalent! :cry:

T7 Design in or near Exeter, have quite an extensive selection of nice looking radiator cooling fans, but they also seem rather expensive, not including the mounting hardware and other components.

T7 Design Ltd, Unit 4, Clyst Units, Cofton Road, Marsh Barton, Exeter, EX2 8QW, UK

Tel. +44 (0) 1392 423 390

Fax. +44 (0) 7595 975 777

E-mail: info@t7design.co.uk

https://www.t7design.co.uk/

Quote:
Manufacturers tend to specify fan-characteristics under free-air conditions, with no regard given to air-flow restrictions, either on the suction or discharge sides of the fan, so it’s difficult to predict how fans would perform in any given radiator-cooling application. Ideally one would experimentally investigate their performance using appropriate test rigs and instrumentation (something I did with HVAC systems at Haden Carrier’s Group Central Laboratories), but sadly I no longer have access to such facilities!

In the technical specifications for the SPAL fans, T7 Design quote maximum air-flow rates, which as I had surmised, fundamentally refers to the air-flow rates that are obtainable under free-air conditions.

https://www.t7design.co.uk/products/rad ... -fans.html

SPAL Radiator Fan - 13.8" (350mm) Push VA08-AP71/LL-53S | £168.00 = £140.00 + VAT

https://www.t7design.co.uk/spal-radiato ... l-53s.html

SPAL Radiator Fan - 13.0" (330mm) Pull VA13-AP70/LL-63A 1718cfm | £129.00 = £107.50 + VAT

https://www.t7design.co.uk/spal-radiato ... l-63a.html

SPAL Radiator Fan - 12" (305mm) Push VA10-AP70LL-61S 1292cfm | £120.00 = £100.00 + VAT

https://www.t7design.co.uk/spal-radiato ... l-61s.html

Surprisingly, whilst researching SPAL radiator cooling fans, I also stumbled upon electrical engine-coolant pre-heaters made by Calix, which also featured on the website of T7 Design in or near Exeter.

https://www.t7design.co.uk/

https://www.t7design.co.uk/engine-heating.html

Quote:
A word about airflow and possible stalling fans. There is a design flaw in nearly every water cooled car that trumps every best effort by manufacturers (or US) at providing good airflow through the engine bay. That being the fact that there is a vertical bulkhead behind the engine that, along with closed bonnet above and solid flitches to either side, effectively acts like a cul de sac, stopping the airflow through the engine bay dead in it's tracks. In our configuration with the rad at the front of the car, it's almost inevitable.

The ONLY exceptions I can think of are the BMC mini, 1100, 1300, Maxi and 1800 where air comes into the engine bay through the grille, hits the bulkhead and o/s flitch and bonnet (and engine) and gets an exit by passing through the rad and out though a convenient vent in the N/S flitch. This is a LOT more efficient, the air is not heated by the rad until it's almost out of the bay and the engine has COLD air direct from the grille passing over it rather than hot air already heated by the radiator, inspired work from Issigonis. This system actually uses the pressure build up in the engine bay to it's advantage, because of this, these cars need relatively smaller radiators.

Short of relocating the rad in a similar fashion, which might be very tricky, I recommend a decent batch of louvres at the rear of the bonnet, it gives all that pressure somewhere to go whilst driving and allows the built up hot air under the bonnet to dissipate harmlessly upwards when stationary in traffic. A couple of beneficial side effect of louvres are that the carburettor(s) stay cooler, less chance of fuel vaporisation with ethanol added fuels and the windscreen clears quicker on icy mornings from hot air being pushed up through the louvres onto the screen when driving.

Steve

I suspect that post-vintage, RWD car designers / stylists, hoped that warm air entering the engine bay, would exit via the transmission tunnel at the rear of the engine bay, beneath the bulkhead.

I recall that many vintage cars, with two-piece, central, longitudinally-hinged bonnets, had louvred slots in the vertical sides of said bonnets, which I surmise served the purpose you describe. I am told that at least some relatively-modern, high-performance cars, also feature such louvres, in the horizontal, front-hinged or rear-hinged bonnets.

Not being a sheet-metal worker by either training or experience, I am unsure how one would cut & shape, either internal or external louvres, in an existing Toledo or Dolomite bonnet, but I suspect there might be a special tool designed for the purpose. One would need to locate these louvres, so that rain-water did not drain onto any vital electrical or ignition-system components.

It would be interesting to somehow measure, the air-flow rate into the engine bay of a Toledo or Dolomite, before and after the addition of louvres! I can think of various ways in which this might be done, if one had access to the appropriate facilities, which ideally would include an automotive wind-tunnel!

Quote:
The bottom short radiator brackets are different on a Toledo , they angle up towards the radiator.

When you say that the Toledo’s bottom radiator-brackets are different, do you mean they are different from those of the Dolomite 1300 or the Dolomite 1500 or both?
Both as when the Dolomite 1300 / 1500 came out the had the same deeper radiator as a triumph 1500tc, only the Toledo had the short radiator.

_________________
1973 yellow Sprint L reg
1979 1500 SE T reg
1979 1500 SE V reg
1980 vermillion 1500hl W reg
1975 green 1500tc auto P reg
1971 wedgewood blue 2000 auto mk2 J reg
1979 Sandglow 1500HL auto V reg
1972 valencia blue Toledo 2 dr K reg
1973 Brown Toledo 2 dr L reg
1973 Green Toledo 2 dr L reg
1977 white Datsun 100a f2 S reg
1983 White Toyota Tercel 4x4
1987 Brown Toyota Tercel 4x4
1988 Blue Toyota Tercel 4x4
1999 Toyota Corolla vvti est
2005 Ford ranger thunder XLT
because one triumph just isnt enough


Top
   
PostPosted: Thu Oct 14, 2021 11:52 am 
Offline
Future Club member hopefully!
Future Club member hopefully!

Joined: Tue May 06, 2014 4:38 pm
Posts: 535
Location: South Benfleet, Essex
Quote:
The bottom short radiator brackets are different on a Toledo , they angle up towards the radiator.
Quote:
When you say that the Toledo’s bottom radiator-brackets are different, do you mean they are different from those of the Dolomite 1300 or the Dolomite 1500 or both?
Quote:
Both as when the Dolomite 1300 / 1500 came out they had the same deeper radiator as a triumph 1500tc, only the Toledo had the short radiator.


It would appear from Steve Boitoult’s posting as follows, on Wednesday, 6th October 2021 @ 8:57 pm, that both the 1970~76 Triumph Toledo 1300 and 1976~80 Triumph Dolomite 1300 shared the same short radiator, given that they both appear to be of part No. 518954, whereas the Triumph Toledo 1500 (export model) and 1976~80 Triumph Dolomite 1500 & 1500HL, all have the long radiator of part No. 518955, which is consistent with the information I gleaned earlier from Rimmer Brothers’ September 1998 catalogue for the Triumph Dolomite 1300 and 1500.

Board index » The Triumph Dolomite Club » Dolomite-related [Start here!] » A question for 1300 & 1500cc owners -Does your car have deflector boards fitted

https://forum.triumphdolomite.co.uk/vie ... 15#p339009
Quote:
Original Toledo radiators are shorter than 1300/1500 dolomites.
Quote:
That's interesting! I shall have to compare my original 1974 Triumph Toledo 1300 radiator with the late-model, Triumph Dolomite 1500 HL radiator that I salvaged.
Quote:
I finally got around to measuring the important dimensions of my original 1974 Triumph Toledo 1300 radiator and of the late-model, Triumph Dolomite 1500 HL radiator that I salvaged, which I have posted in another topic thread as follows:

Board index » The Triumph Dolomite Club » Dolomite-related [Start here!] » Substituting a Triumph Dolomite 1500 HL Engine Cooling-System Radiator into a Triumph Toledo 1300

https://forum.triumphdolomite.co.uk/vie ... 92#p338724

The Dolomite 1500HL radiator is 75 mm (i.e. circa 3 inches) longer than the Toledo 1300 radiator and both are of identical width. What I don’t have for the purpose of comparison, are the corresponding dimensions of the 1976~80 Triumph Dolomite 1300! Would anyone care to oblige?

Quote:
From my 1973 Toledo parts list and my 76> Dolomite parts list (published Feb 1981), the Toledo and Dolomite 1300 radiator is part number 518954 and the (export only) Toledo 1500, Dolomite 1500 and 1500HL radiator is part number 518955.

Steve

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Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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PostPosted: Thu Mar 17, 2022 12:00 pm 
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Quote:
I found the following reference from Steve Boitoult, posted more than 5¼ years ago, on Saturday, 7th May 2016 @ 5:45 pm:

Board index » The Triumph Dolomite Club » Restoration Projects » '72 Toledo 'Sonic' Shopping list created.

https://forum.triumphdolomite.co.uk/vie ... 74#p338774

« I have a fair used rad for a 1500HL which will fit the Toledo »

Hence, I deduce that I have reasonable expectations of completing this upgrade without too much difficulty! Hopefully, it won’t involve much more than sourcing a substitute bottom radiator hose (part No. GRH552) and a replacement electric fan with low-profile motor and 14 inch diameter fan blades. :D
Quote:
As to global warming, I don't think a 1degree change in average ambient temps will make any difference, What will is if the salvaged radiator is internally poor and has any tubes blocked. Quite possible if the car had a miserable few years with lack of maintenance. And impossible to check at home, though old radiator shops used to be able to test flow. And even remove a tank and poke tubes clear.
Quote:
It’s not the Global changes in average ambient air temperatures, of just a few degrees Celcius, that are so significant in this regard, but the relatively short-duration, extreme events, such as the major high-temperature heat waves that were experienced in southern Europe and western Canada & USA earlier this year, and which are becoming more common in Great Britain. Such high temperatures in British Columbia, where they suffered major forest fires and the destruction of one town were unprecedented, and Sicily in southern Europe also experienced uncomfortably high temperatures, peaking at 48•8 ºC. In such extreme high-temperature conditions, a vehicle with an air-cooled engine would probably be more appropriate!

The late-model Triumph Dolomite 1500 HL radiator looked relatively new when I salvaged it more than 10 years ago. The black paint appeared relatively fresh looking and there was negligible sign of corrosion of the radiator’s riveted vertical steel supports (onto which the mounting brackets are bolted), but the removable mounting brackets were noticeably rusty, so they will need to be wire-brushed with the electric drill, soaked in dilute phosphoric acid solution and repainted before I reuse them.

Being able to remove the top or bottom radiator tank might be useful, if one wanted to incorporate one or more heat-exchange tubes, for heating the windscreen-washer fluid!

Quote:
The bottom short radiator brackets are different on a Toledo , they angle up towards the radiator.

I am pleased to report that I have finally found in my garage, the radiator mounting brackets associated with the Triumph Dolomite 1500 HL radiator, that I salvaged several years ago from the local fire station opposite my home.

I can undertake a trial fitment of the Triumph Dolomite 1500 HL radiator in my 1974 Triumph Toledo 1300 “HL Special”, once I have found all the necessary bolts!

As I suspected they would be, the Triumph Dolomite 1500 HL radiator’s pair of top mounting brackets are identical to the Triumph Toledo 1300 radiator’s top mounting brackets; whilst in contrast, the pairs of bottom mounting brackets are very different, as I also suspected.

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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PostPosted: Thu Mar 17, 2022 9:22 pm 
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Joined: Sun Aug 21, 2011 5:12 pm
Posts: 7005
Location: Highley, Shropshire
I tend to remove the OHV radiators complete with the 4 mount brackets, so I don't lose them and the correct brackets stay on the correct radiators.

Which is why I said that a 1500 rad is a straight swap into a Toledo all those years ago. In that pre-assembled form, it IS!

On underbonnet pressure from the grille/rad into the engine bay, I can't offer figures, but an accidental experiment that happened to me many years ago may be cogent.

Back in the 80s, a friend owned a rather souped up Triumph Vitesse which was fitted with a GRP bonnet/front end. He had a perennial problem with the bonnet securing latches undoing themselves on the road. When this occurred, at any speed over 50mph the back end of the bonnet would start to lift from air pressure underneath it. The faster you drove, the higher the bonnet would lift, until a point at about 80mph where the pressure equalized. But by this point, half the windscreen was obscured by the fluttering bonnet. Not an ideal situation, by any standard.

Because it was only a GRP bonnet, I had no qualms about cutting it about. I got a couple of large louvre panels off an old washing machine side panel and inserted (after cutting matching holes in the bonnet top near the bulkhead) one either side. This not only aided cooling considerably but stopped the bonnet from undoing it's latches remotely, I guess because the load on them was less. Even so, to prevent it entirely I fitted a pair of hold down pins with spring catches vertically at the rear edge of the bonnet as belt and braces.

I've tried a similar experiment on a Dolomite (leaving the bonnet unlatched when driving it is all it takes) with similar results. Predictably, the heavier steel bonnet doesn't achieve V2 (min flying speed) until about 60mph and max height doesn't go much above 1/3 of the way up the screen at almost 90mph.

Fitting louvres that look good as well as being functional in a steel Dolomite bonnet is a rather more complex and expensive affair, which not only entails shipping the bonnet to a specialist to have the louvres stamped into the panel, but also, the bonnet will need a complete repaint too, which will add another £150 to the £2-300 cost of the louvres. Yes, it's very expensive but in my opinion, well worth it and there ARE some subsidiary benefits as well. One of the best, is that, in these days of ethanol in petrol, the underbonnet area around the carb(s) is kept cooler, reducing the possibilty of fuel vaporisation in high ambient temps and traffic conditions. Hot air from the louvres helps warm the screen on icy mornings. There is a slight improvement in the car's drag co-efficient and by redirecting some air up over the roof, rather than all down under the car, it's cleaner aerodynamically. Though none of these improvements are exactly large, anything is better than nothing.

Also, louvres look cooler than a polar bear at Christmas!

I just "happen" to have a customer's louvred bonnet in the garage awaiting fitment, i'll take some pictures tomorrow.

Steve

_________________
'73 2 door Toledo with Vauxhall Carlton 2.0 8v engine (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine (The Dolomega)
'72 Triumph 1500FWD in Slate Grey, Now with RWD and Carledo powertrain!

Maverick Triumph, Servicing, Repairs, Electrical, Recomissioning, MOT prep, Trackerjack brake fitting service.
Apprentice served Triumph Specialist for 50 years. PM for more info or quotes.


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PostPosted: Thu Mar 17, 2022 9:54 pm 
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Location: Midhurst, West Sussex.
Steve,

I would be very interested to see the pictures, as I am thinking of getting my bonnet louvred but I am not too sure where exactly in the bonnet it would best to get them pressed. I am often in Horsham, so I could drop it off at Cool Louvres to be done.

Glen.


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PostPosted: Tue Mar 22, 2022 7:07 pm 
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Joined: Tue May 06, 2014 4:38 pm
Posts: 535
Location: South Benfleet, Essex
Quote:
I tend to remove the OHV radiators complete with the 4 mount brackets, so I don't lose them and the correct brackets stay on the correct radiators.

Which is why I said that a 1500 rad is a straight swap into a Toledo all those years ago. In that pre-assembled form, it IS!

The problem with leaving the brackets bolted to the radiator, was that the complete assembly takes up more storage space and the awkward overall shape is more difficult to store. There was also the greater possibility of the brackets and/or the radiator side-panels getting damaged. I would normally interpret OHV to be an abbreviation of overhead valve, but I’m not sure how that would be applicable to radiators!?!

Quote:
Hot air from the louvres helps warm the screen on icy mornings.

Our American colonial-cousins across the other side of the Atlantic Ocean, have the option of retro-fitting accessory electrically-heated strips, on the inside of the front windscreen, to defrost the areas along the bottom and sides, to thaw any ice or frost in the regions where parked wiper blades might get frozen onto the windscreen and any built-up deposited snow cleared by the wipers, at the limits of wipers’ swept area. These are available from Planned Products LLC, in Boulder, Colorado.

Planned Products LLC, 4699 Nautilus Court S., Suite 201, Boulder, Colorado, CO 80301-5307, USA
Tel: 303.682.0274
Fax: 303.682.0678
E-mail: info1@frostfighter.com
Website: https://frostfighter.com

https://frostfighter.com/catalog.htm

https://frostfighter.com/clear-view-fro ... osters.htm

Quote:
I just "happen" to have a customer's louvred bonnet in the garage awaiting fitment, i'll take some pictures tomorrow.
Quote:
I would be very interested to see the pictures, as I am thinking of getting my bonnet louvred but I am not too sure where exactly in the bonnet it would best to get them pressed. I am often in Horsham, so I could drop it off at Cool Louvres to be done.

Glen.

I imagine that the best location for the louvres, would be at one or more locations where the difference in static pressure between the underside and topside (i.e. ventral and dorsal surfaces) of the bonnet is at its greatest. However, the distribution of differential pressure might change once louvres are introduced!

Several years ago, whilst undertaking some on-line research, I stumbled upon the website of the Australian on-line magazine Autospeed.com, which features some interesting articles pertinent to this and other topic threads:

Julian Edgar, “Undertrays, Spoilers & Bonnet Vents, Part 1 - Designing, siting, installing and testing!”, DIY Tech Features Section, Issue: 695, 21st April 2015

https://www.autospeed.com.au/a_2159/cms/article

Julian Edgar, “Undertrays, Spoiler & Bonnet Vents, Part 2 – Designing, siting, installing and testing an undertray/spoiler”, DIY Tech Features Section, Issue 696, 5th May 2015

https://www.autospeed.com.au/a_2160/cms/article

Julian Edgar, “Undertrays, Spoiler & Bonnet Vents, Part 3 – Designing, siting, installing and testing bonnet vents”, DIY Tech Features Section, Issue 697, 19th May 2015

https://www.autospeed.com.au/cms/a_2162 ... lararticle

Graham Pring, “Chasing Overheating - Finding why a V8 Cobra replica was getting hot under the collar”, DIY Tech Features Section, Issue 650, 25th June 2013

https://www.autospeed.com.au/cms/a_111195/article

Graham Pring, “Chasing Overheating Again! - A different electric fan”, DIY Tech Features Section, Issue 651, 9th July, 2013

https://www.autospeed.com/cms/a_111234/ ... lararticle

Graham Pring &Julian Edgar, “Water Pump Testing - Got overheating problems? Here's how to accurately test your water pump in a few hours for under $15”, Technical Features Section, Issue: 484, 11th June 2008

https://www.autospeed.com.au/cms/a_110478/article

_________________
Regards.

Nigel A. Skeet

Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.

https://www.linkedin.com/profile/view?id=308177758

Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)

Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club


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PostPosted: Tue Mar 22, 2022 11:20 pm 
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TDC Shropshire Area Organiser

Joined: Sun Aug 21, 2011 5:12 pm
Posts: 7005
Location: Highley, Shropshire
Quote:
Quote:
I tend to remove the OHV radiators complete with the 4 mount brackets, so I don't lose them and the correct brackets stay on the correct radiators.

Which is why I said that a 1500 rad is a straight swap into a Toledo all those years ago. In that pre-assembled form, it IS!

The problem with leaving the brackets bolted to the radiator, was that the complete assembly takes up more storage space and the awkward overall shape is more difficult to store. There was also the greater possibility of the brackets and/or the radiator side-panels getting damaged. I would normally interpret OHV to be an abbreviation of overhead valve, but I’m not sure how that would be applicable to radiators!?!

Quote:
Hot air from the louvres helps warm the screen on icy mornings.

Our American colonial-cousins across the other side of the Atlantic Ocean, have the option of retro-fitting accessory electrically-heated strips, on the inside of the front windscreen, to defrost the areas along the bottom and sides, to thaw any ice or frost in the regions where parked wiper blades might get frozen onto the windscreen and any built-up deposited snow cleared by the wipers, at the limits of wipers’ swept area. These are available from Planned Products LLC, in Boulder, Colorado.

Planned Products LLC, 4699 Nautilus Court S., Suite 201, Boulder, Colorado, CO 80301-5307, USA
Tel: 303.682.0274
Fax: 303.682.0678
E-mail: info1@frostfighter.com
Website: https://frostfighter.com

https://frostfighter.com/catalog.htm

https://frostfighter.com/clear-view-fro ... osters.htm

Quote:
I just "happen" to have a customer's louvred bonnet in the garage awaiting fitment, i'll take some pictures tomorrow.
Quote:
I would be very interested to see the pictures, as I am thinking of getting my bonnet louvred but I am not too sure where exactly in the bonnet it would best to get them pressed. I am often in Horsham, so I could drop it off at Cool Louvres to be done.

Glen.

I imagine that the best location for the louvres, would be at one or more locations where the difference in static pressure between the underside and topside (i.e. ventral and dorsal surfaces) of the bonnet is at its greatest. However, the distribution of differential pressure might change once louvres are introduced!

Several years ago, whilst undertaking some on-line research, I stumbled upon the website of the Australian on-line magazine Autospeed.com, which features some interesting articles pertinent to this and other topic threads:

Julian Edgar, “Undertrays, Spoilers & Bonnet Vents, Part 1 - Designing, siting, installing and testing!”, DIY Tech Features Section, Issue: 695, 21st April 2015

https://www.autospeed.com.au/a_2159/cms/article

Julian Edgar, “Undertrays, Spoiler & Bonnet Vents, Part 2 – Designing, siting, installing and testing an undertray/spoiler”, DIY Tech Features Section, Issue 696, 5th May 2015

https://www.autospeed.com.au/a_2160/cms/article

Julian Edgar, “Undertrays, Spoiler & Bonnet Vents, Part 3 – Designing, siting, installing and testing bonnet vents”, DIY Tech Features Section, Issue 697, 19th May 2015

https://www.autospeed.com.au/cms/a_2162 ... lararticle

Graham Pring, “Chasing Overheating - Finding why a V8 Cobra replica was getting hot under the collar”, DIY Tech Features Section, Issue 650, 25th June 2013

https://www.autospeed.com.au/cms/a_111195/article

Graham Pring, “Chasing Overheating Again! - A different electric fan”, DIY Tech Features Section, Issue 651, 9th July, 2013

https://www.autospeed.com/cms/a_111234/ ... lararticle

Graham Pring &Julian Edgar, “Water Pump Testing - Got overheating problems? Here's how to accurately test your water pump in a few hours for under $15”, Technical Features Section, Issue: 484, 11th June 2008

https://www.autospeed.com.au/cms/a_110478/article
Here are the pics :-

Image

Image

As you can see from the second image, you are constrained by the framing as to exactly where and how many louvres to fit. Then, on the slant engined cars, the centre rear section is directly above the distributor, so that's a non starter too.

I've identified the area near the bulkhead as being the one that gets the hottest air under it when the car is stationary, whether the fan is running or not. This is probably due to the lack of air circulation at this point. With the car in motion or the fan running, air is forced back and DOWN under the car, leaving a wedge of air trapped by bonnet and bulkhead that does little more (because of turbulence)than turn over on itself, getting hotter all the time. So this is surely the best place to put the louvres. Even with the car stationary, hot air rises and the rear edge is the highest point. This is important for avoiding fuel vaporisation in carburettored cars , sitting in traffic, especially during high ambient temps.

OK so far, but why not fill the bonnet with as many louvres as you can get in, more is better right? Well......Not exactly! It has to do with that pressure differential. By cutting the louvres you allow some pressure to escape upwards. And it's not escaping into a vacuuum, or even an area of very low pressure, but an area of fairly high pressure (though it's considerably lower than under the bonnet) So the more louvres you cut, the more you run into the law of diminishing returns.

I've disinguished the OHV (which is indeed overhead valve) engine's radiators as they CAN be removed either with or without the brackets. On the slant engined cars it's not possible to withdraw the radiator from the brackets as they wrap around the ends of the core.

On the subject of screen heating, i'd be suspicious of anything stick on! I remember well (as i'm sure you do) the horrible stick on rear window heaters that were sold as aftermarket add ons by the like of Smiths and Radyot in the 60s. Which never stayed stuck on for long and would get the element broken if you looked at it too hard. I wasn't a fan then and i'm even less of one now, spoilt by modern tech I guess!

However, since my Dolomites are daily drivers, summer and winter the subject DOES interest me. The Dolomega has an excellent heater that warms the screen quickly but it could be better. I don't have louvres as the main reasons for using them (carbs and vaporisation) don't apply as I have EFi. But it has come to my attention that at least one person is supplying Dolomite screens with heating elements pre-fitted in clear or sundym style. And for a price considerably lower than Pilkingtons are quoting for a standard Sundym replacement. Since the Dolomega has sundym glass but a (aftermarket) clear screen i'm seriously considering this!

The only potential downside is the power draw of such items. Whilst a Dolomite or Toledo's weedy 35a alternator can cope with a stock HRW that will clear the back window in a leisurely 10 mins or so, most heated windscreens i've encountered do the job in 15-45 SECONDS! OK they aren't running for anything like as long but the draw must be phenomenal. Doesn't bother ME as the Dolomega has a 140a Alternator and a 96AH battery but i'm not sure i'd like to subject a standard Dolomite system to such loads!

Steve

_________________
'73 2 door Toledo with Vauxhall Carlton 2.0 8v engine (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine (The Dolomega)
'72 Triumph 1500FWD in Slate Grey, Now with RWD and Carledo powertrain!

Maverick Triumph, Servicing, Repairs, Electrical, Recomissioning, MOT prep, Trackerjack brake fitting service.
Apprentice served Triumph Specialist for 50 years. PM for more info or quotes.


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PostPosted: Sat Mar 26, 2022 11:49 pm 
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Joined: Sun Nov 16, 2014 12:46 am
Posts: 423
Location: Midhurst, West Sussex.
Steve,

That bonnet looks good. Although I do like the idea of lining the outside edge of the louvres up with the standard intake vents at the rear of the bonnet, if the reinforcing ribs leave enough room.

Glen.


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