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PostPosted: Sat Aug 01, 2015 3:32 pm 
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Here's an "interesting" article that in came across in the AA "Drive" magazine a few decades ago, about the importance of recognising the importance of warning lights and the advantages supplementary instrumentation.

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The rationale behind the article, was that by the sensible use and interpretation of a comprehensive instrumentation system, developing problems could be identified in their infancy, enabling one to avert disaster in extreme cases, but more usually to plan preventative maintenance or repair, which would avoid breakdowns occurring.

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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


Last edited by naskeet on Tue Aug 04, 2015 3:00 pm, edited 1 time in total.

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PostPosted: Sat Aug 01, 2015 3:35 pm 
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In a related topic thread, the following comments were made:
Quote:
I can understand the need for an oil temp gauge in an air-cooled Veedub but in a water-cooled engine, oil pressure and water temp is enough, the oil's not going to boil without the water boiling first!

Steve
Although particularly important for air-cooled engines, together with a cylinder-head temperature gauge, an oil-temperature gauge is also important for VW & Audi and other water-cooled engines, which was why factory-fitted VDO 50~150 ºC oil-temperature gauges, could often be salvaged at my local car breaker’s yards during the 1990s, and resold at a modest profit to fellow club members, for retro-fitment to their VW Transporters with either air-cooled or water-cooled engines.

You might find the following references & quotations to be of interest:

A. Graham Bell, “Performance Tuning in Theory & Practice (Four Strokes)”, Haynes Publishing Group, 1981, ISBN 0-85429-275-6, Chapter 8 – Lubrication & Cooling, Pages 187~189.

« . . . Besides polymers, an oil may contain an anti-oxidant, a detergent and a foam suppressant. Oxidation occurs due to the presence of oxygen and combustion by-products in the oil and due to the temperature of the oil itself. As the oil temperature increases past 100ºC, the rate of oxidation accelerates and the anti-oxidant becomes less effective. . . . »

« . . . No matter how good your oil is, it must be maintained at the correct temperature to lubricate effectively. A good deal of engine wear takes place because engines are operated with cold oil and/or water. An engine should never be driven hard until the oil reaches 50ºC. The ideal operating temperature is 80~90ºC. It can go as high as 150ºC for short periods but oil breakdown and excessive oxidation will take place above this temperature. . . . »

« . . . In hotter climates, high performance road vehicles may also need an oil cooler. It is always a worry recommending an oil cooler for a road car or bike because for a good deal of the time, the oil will be over-cooled, particularly during winter. Cold oil promotes engine wear and sludge build-up, so be sure to fit a shutter or blind in front of the oil cooler to prevent air passing through when driving and/or weather conditions are not conducive to a high oil temperature. »

« Before you decide on an oil cooler for a road machine, be sure you really need one. Fit an oil temperature gauge and determine your oil operating temperature in mid-summer. If under normal driving conditions your oil temperature is in excess of 140ºC, fit an oil cooler. However, if it stays around 110~120ºC and climbs to 140ºC only when you run at full throttle for quite a few miles, you will be wasting your time and causing yourself unnecessary trouble by fitting an oil cooler. . . . »


During the two winter seasons (1987/88 & 1990/91) that I used our 1973 VW 1600 Type 2, the single Minnow Fish carburettor, with ‘pancake’ paper-element air filter on top, suffered from chronic icing (despite the 90W electric de-icing element) and the oil temperature rarely increased much beyond 50 °C; a condition to which I would have been oblivious, without the oil-temperature gauge. On one occasion, fuel dilution of the oil was so severe, the ‘sump’ contained about 1 litre of petrol & water, in addition to the 2•5 litres of oil! Carburettor icing is well known on air-cooled VWs, having a single carburettor (particularly those which have inadequate air pre-heating and/or inlet-manifold, exhaust heating!) and has also been experienced occasionally with twin-carburettor installations, which many had thought to be immune.

_________________
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 Tue Aug 04, 2015 3:01 pm, edited 1 time in total.

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PostPosted: Sat Aug 01, 2015 8:55 pm 
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Is it true that oil pressure warning lights often only come on at very low pressures - around 5 PSI - meaning that serious trouble may already be irreversible when they light up?


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PostPosted: Sun Aug 02, 2015 4:02 pm 
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Quote:
Is it true that oil pressure warning lights often only come on at very low pressures - around 5 PSI - meaning that serious trouble may already be irreversible when they light up?
Yep! 4-6 psi is typical! Though you can get ones designed for racing that come on at a more sensible 20 psi.

Steve

_________________
2 door '73 Toledo with Vauxhall Carlton engine OWF 797M (The Carledo)
Vermillion (and Rust) Sprint Auto EGP 247T (The Dolomega)
'91 Cavalier 2ltr 8v auto
'95 Cavalier 2ltr 16v auto
Spectrum Auto Services, Servicing, Repairs, MOT prep. Apprentice served Triumph Specialist for 40 years and home of Maverick Triumph.PM for more info or quotes.


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PostPosted: Mon Aug 03, 2015 3:45 pm 
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Quote:
Quote:
Is it true that oil pressure warning lights often only come on at very low pressures - around 5 PSI - meaning that serious trouble may already be irreversible when they light up?
Yep! 4-6 psi is typical! Though you can get ones designed for racing that come on at a more sensible 20 psi.

Steve
I echo that observation, but I'm more accustomed to working in Bar or kPa or kN/m².

So far, I have yet to retrofit an oil-pressure gauge to the Toledo, but my 1973 VW Type 2's air-cooled engine, idles at 1·0 Bar (i.e. circa 14·7 PSI, if I recall correctly), increasing to 3·0 Bar at driving speeds, once the oil has warmed-up from cold. Hence, an oil-pressure switch of about 0·7~0·8 Bar would probably be ideal for my air-cooled VW engine, but I'm not sure what would be most appropriate to my Toledo's A-Series engine.

_________________
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: Mon Aug 03, 2015 8:42 pm 
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Quote:
Quote:
Quote:
Is it true that oil pressure warning lights often only come on at very low pressures - around 5 PSI - meaning that serious trouble may already be irreversible when they light up?
Yep! 4-6 psi is typical! Though you can get ones designed for racing that come on at a more sensible 20 psi.

Steve
I echo that observation, but I'm more accustomed to working in Bar or kPa or kN/m².

So far, I have yet to retrofit an oil-pressure gauge to the Toledo, but my 1973 VW Type 2's air-cooled engine, idles at 1·0 Bar (i.e. circa 14·7 PSI, if I recall correctly), increasing to 3·0 Bar at driving speeds, once the oil has warmed-up from cold. Hence, an oil-pressure switch of about 0·7~0·8 Bar would probably be ideal for my air-cooled VW engine, but I'm not sure what would be most appropriate to my Toledo's A-Series engine.
There is no idle oil pressure recommended for the Triumph engine, all the books specify is that there should be at least 50 psi (3.5 bar) at 2000rpm with a warm engine. but an old, tired engine will frequently have a bit of hot idle light flicker (so about 5psi) to worry you and still run happily for years if not abused!

Steve

_________________
2 door '73 Toledo with Vauxhall Carlton engine OWF 797M (The Carledo)
Vermillion (and Rust) Sprint Auto EGP 247T (The Dolomega)
'91 Cavalier 2ltr 8v auto
'95 Cavalier 2ltr 16v auto
Spectrum Auto Services, Servicing, Repairs, MOT prep. Apprentice served Triumph Specialist for 40 years and home of Maverick Triumph.PM for more info or quotes.


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PostPosted: Tue Aug 04, 2015 3:06 pm 
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Quote:
Quote:
Quote:
Is it true that oil pressure warning lights often only come on at very low pressures - around 5 PSI - meaning that serious trouble may already be irreversible when they light up?
Yep! 4-6 psi is typical! Though you can get ones designed for racing that come on at a more sensible 20 psi.

Steve
There is no idle oil pressure recommended for the Triumph engine, all the books specify is that there should be at least 50 psi (3.5 bar) at 2000rpm with a warm engine. but an old, tired engine will frequently have a bit of hot idle light flicker (so about 5psi) to worry you and still run happily for years if not abused!

Steve
Several VW & Audi water-cooled engines, were factory-fitted with two oil-pressure switches, with rated switching pressures of 0•30 ± 0•15 Bar (circa 4•4 ± 2•2 PSI) and 1•8 ± 0•20 Bar (circa 26•5 ± 2•9 PSI). Using appropriate electronic circuitry, the high-pressure, break-on-fall switch (VW part No. 056 919 081E), only illuminated the warning light, when the oil pressure fell below 1•8 ± 0•20 Bar iff the engine revs were in excess of 2,000 rpm. A similar scheme could probably be used with a Triumph engine.

If this system were used on an air-cooled VW engine, I would personally, have used a low-pressure switch, having a greater switching pressure of slightly less than the typical oil pressure at idling speed, which for my previous engine was 1•0 Bar (circa 14•7 PSI) after 64,000 miles. The 1•8 ± 0•20 Bar switching pressure of the high-pressure switch, would probably be okay; the Volkswagen factory having specified a minimum tolerable oil pressure of 2•0 Bar with SAE 30 monograde oil @ 70ºC oil temperature, at 2,500 rpm.

_________________
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 Aug 04, 2015 3:10 pm 
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Battery Charging & Electrical Supply
Quote:
Ammeters were dropped in favour of voltmeters for the very good reason that ALL the car’s circuitry save only the high amp starter circuit had to run through the gauge, this was fine on older cars with only a handful of circuits but putting a modern on this system would be crazy. Plus if the ammeter packs up (as it had on a TR6 I was working on recently) EVERYTHING stops working!

Steve
It is undoubtably very inconvenient if an ammeter fails and becomes open-circuit, but one can readily bypass an ammeter if this situation arises. It is similarly inconvenient, if either one or both of a Triumph’s two fuses (direct battery supply & ignition-controlled supply) fail for whatever reason.

The voltmeter and ammeter complement each other, so both are desirable for monitoring the electrical system.

The principal purpose of an ammeter, is to show whether the battery is being charged or discharged rather than indicate the total current being supplied by the generator (i.e. dynamo or alternator) and/or battery to the electrical system (discounting the starter motor). This is why automotive ammeters have a scale encompassing both positive & negative readings!

The electrical system is prone to faults, which might cause a breakdown, less than optimum performance and more besides; about which, little if any information is provided, by the standard ignition warning light.

Even when the ignition warning light is extinguished, one cannot be sure that the battery is being charged; only that the difference in voltage between the battery and the generator (dynamo or alternator), is insufficient to cause a 12 V bulb to glow. In fact, the battery may even be discharging! To satisfactorily monitor the behaviour of the electrical system, one needs to measure both voltage and current flow; necessitating a voltmeter (sometimes known as a battery condition meter) and an ammeter.

In order to maintain the health of a lead-acid car battery, it is important that it should be fully recharged; ideally requiring a generator voltage of about 13•9~14•3 V (see Tony Tranter, "Automobile Electrical Manual", Haynes Publishing Group, 1983, Page 57). If the applied voltage is too low, full charge capacity will never be restored, resulting in the battery charge capacity and maximum discharge rate, progressively deteriorating, owing to sulphation of the plates. The principal purpose of the voltmeter, is to ensure that the generator's voltage regulator, is functioning correctly.

Some batteries are marked with the warning, that the external charging voltage, applied across the battery terminals, by the generator or mains charger, should not exceed 14•4 V. Severe overcharging, causes the battery to overheat, boiling off the sulphuric acid and possibly buckling the plates which may lead to an internal short, in one or more cells; rendering the battery unserviceable. Sulphuric acid vapour can also result in extensive corrosion, in surrounding body panels, as some owners have found to their cost.

Even if the optimum charging voltage is applied, it is not certain that the battery is being adequately recharged. This may arise if there are significant voltage drops in the cables or connections (very likely if vehicles are more than a few years old and haven't been adequately maintained or the cable connectors are merely crimped and not soldered), or the battery is nearing the end of its useful life, owing to sulphation or an internal short.

Under some conditions, the battery may even be discharging; supplementing the current provided by the generator, to meet high electrical loads, which typically occur, when driving in slow moving traffic, in cold, damp and dark conditions. The only way to be sure that the battery is being charged, is to have an ammeter in the circuit, directly between the generator and the battery, which will indicate the instantaneous rate of charging or discharging, but not the total quantity of charge stored.

A remote-shunt ammeter (made by VDO, Lucas and others), which requires only light-duty cable, is the most appropriate (see Austin Jack Smith, "Ampere and Volt Meters", Library Section, type2.com) to the rear-engined VW, but the more widely available, conventional internal-shunt ammeter, may also be used, albeit in conjunction with several metres of ultra-heavy-duty cable.

http://www.type2.com

As a 12V battery approaches a fully charged state, the voltage across its terminals, may rise to as much as 15•0~16•2V, dependent upon the applied voltage of the charging source. When the charging current ceases (i.e. the generator or battery charger has ceased operating), the battery terminal voltage quickly falls to about 12•6V. As the battery discharges at a nominal rate (effect of high current load is discussed later, in relation to starter motor operation), the terminal voltage falls rapidly from 12•6V to 12•0V, at which it remains for most of the discharge period, until close to the fully discharged condition, it rapidly diminishes to about 11•8V.

Hence, a voltmeter only gives any indication of the charge stored by a battery, when it is either close to the fully charged or fully discharged conditions. The voltage values cited in the preceding paragraph, assume a battery temperature of 25°C; the voltage diminishing as temperature decreases (a topic in electro-chemistry, covered as part of B.Sc. Chemistry). Before starting their engines in winter, Russian motorists allegedly turn on their headlamps for a short period, so that the current draw, warms the battery, thus increasing the voltage and current available to the starter motor; or so I've been told. It sounds plausible, but I have yet to try it myself!

From the preceding discussion, it is apparent that under most circumstances, a voltmeter and ammeter, only give an instantaneous view of prevailing conditions in the electrical system; any assessment of the state of battery charge, being reliant upon one's recall, of the history of charging and discharging, during the journey, which inevitably tends to be rather subjective. To measure the extent of total battery charge, would require some electronic circuitry, to integrate the charge flow rate with respect to time (i.e. electronics applied to integral calculus), which is readily achievable these days. Such instruments are available from some boat chandlers and are commonly advertised in magazines such as Practical Boat Owner.

Battery suppliers assess battery condition, when fully charged, by conducting a high-rate discharge test, simulating the high current discharge of circa 100 A, which occurs when running a typical starter motor. If one conducts a similar test, by observing the decrease in voltage reading, as the engine is turned over on the starter motor (typically 0•5~0•6 kW rating - circa 42~50 A @ 12 V, for a 1968~79 VW Type 2), one might reasonably expect a reading of about 11V with a new battery, which will progressively diminish with age, as the battery's internal resistance increases, owing to sulphation and other processes.

If a reading as low as 9 V is observed, then the battery is nearing the end of its useful service life. Sulphation may be inhibited by adding to each battery cell (preferably when new), about one heaped teaspoon, of an analytical chemical reagent, known as EDTA (i.e. Ethylene Diamine Tetra-acetic Acid or its Di-sodium salt), which I have done since the mid-1980s, at the recommendation of an analytical chemist, writing about this procedure, in the Motorcaravanners' Club magazine. My family's car batteries typically last about 6~8 years. The battery of my father's Ford Sierra XR4x4, lasted an incredible 13 years!

Whilst on holiday in Sweden in 1982, with my family's 1973 VW 1600 Type 2, we suffered two breakdowns, owing to failure of the dynamo and voltage regulator, on two separate occasions. In the first case, when the dynamo failed, I was warned that something was amiss, by sudden illumination of the ignition warning light, which after inspection of the V-belt, prompted us to visit a Volkswagen agent in Västervik, the next town, where the dynamo was replaced.

When the voltage regulator burned out some days later, the ignition warning light did NOT illuminate at any stage, despite a functional bulb. The first hint of this problem, was when the engine began to judder, in a way which was reminiscent of a faulty cut-out type rotor arm, shorting the HT ignition pulses to earth, at low engine revs, which I had experienced on holiday in Belgium, some years earlier. Having a burnt out voltage regulator, the battery wasn't being charged, so the ignition system and the headlamps (daytime use is compulsory in Sweden, unless one has special daytime running lights), were running on the battery's reserve capacity, leading to a drop in supply voltage.

Having stopped the vehicle on a steep uphill gradient (not the best of places!) and found the rotor arm to be okay, I attempted to restart the engine, but discovered that the battery was virtually flat. Not possessing a starting handle facility in those days (later fitted, owing to sporadic episodes, of the dreaded, 'dead starter motor syndrome'), I was obliged to undertake a rolling start, downhill, in reverse gear; a procedure which I would not generally recommend.

By driving with the headlamps switched off, there was sufficient battery voltage available, to run the ignition system, for several more miles, until we reached Vetlanda, the next large town, where there was a Volkswagen agent. Had we been driving in a country where daytime headlamp use was not required, we would have been stranded on the hill!

Another failure mode of voltage regulators, results in a battery being charged at an excessively high voltage, causing it to overheat, leading to the corrosive sulphuric acid electrolyte being boiled off, and in extreme cases, buckling of the battery's internal electrode plates, which renders it unserviceable. This is something which Ken Brimson (the then VWT2OC membership secretary) experienced in July 2013, with his 1968 VW 1600 Type 2 "Nelly", when returning home from a VW show, at Dettling, Kent, to his home in Winchester, Hampshire.

Not having a dashboard-mounted voltmeter, Ken was oblivious to his electrical-charging-system failure, until he got home. Using a hand-held meter, he discovered that the alternator (not a dynamo, as normally fitted to 1968~73 model-years) was charging at 14½ volts, at engine idle, and circa 16½~17 volts, when the engine was revved to RPM levels, typical of normal driving conditions. In 1987, Ralph Pettitt (1996~2001 Transporter Talk editor), suffered similar alternator voltage-regulator failure, which "destroyed" both batteries of his early-1980s VW 1600 Type 25 diesel campervan, whilst in Croatia (then part of north west Yugoslavia); prompting him to somehow limp home to England, with no on-board battery power.

Given that the output voltage of an alternator, is determined by both the rotor's rotational speed and the current in the magnetic-field coils, the output voltage would be regulated by interrupting or otherwise restricting, the mean current flow to the coils. Hence, with an inoperative voltage regulator, I envisage that the output voltage would increase in proportion to engine speed (hence the defunct batteries!), so one would be obliged to maintain the engine revs below a certain threshold. This could be achieved most readily, by having a dashboard-mounted voltmeter, but knowing the crankshaft to alternator pulley ratio, and something of the alternator's output characteristics, it could also be done indirectly after some calculations, using either an engine tachometer or the speedometer.

_________________
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 Thu Aug 06, 2015 3:01 pm, edited 1 time in total.

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PostPosted: Tue Aug 04, 2015 3:23 pm 
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Engine Inlet-Manifold Vacuum Pressure
Quote:
Personally I like vacuum gauges and one of my triple SUed Zodiacs had 3, one for each carb in a pod atop the dash, I could keep an eye on exactly how my carb balance was doing but then I am a gadget freak! But I wouldn't regard one as NECESSARY, just nice to have and impresses the impressionable. I would hate to have a turbo without a boost gauge but I've never seen an exhaust temp gauge, not even on highly stressed turbo'd jap drift cars.

Steve
I acknowledge that multiple vacuum gauges are used for checking that multiple carburettor installations are balanced, but a single vacuum gauge connected to the inlet manifold (or balance pipe for multiple carburettors), has several functions with regard to monitoring the health of one’s engine and its ancillary systems.

Traditionally, the vacuum gauge has been used as an aid to economical driving, whereby one adjusts the position of the accelerator pedal, to give the greatest reading of vacuum, for a given load. However, it is also a useful instrument for diagnosing a variety of engine conditions and faults, such as:- a clogged air filter; obstructed or damaged exhaust system; air leak at the manifold, carburettor or throttle body gaskets; incorrect valve timing; sticking or leaking valves; worn valve guides; weak valve springs; worn piston rings; retarded ignition timing; a gasket leak between adjacent cylinders (unlikely on an air-cooled VW engine); and more comfortingly, an engine which is in good condition and well tuned.

http://thegaugeshop.com/SMITHS-VACUUM-GAUGE

http://www.bing.com/images/search?q=Smi ... &FORM=IGRE

In general, diagnostic readings are taken with an engine at normal operating temperature and running at idling speed, which are described as follows; the gauge illustration numbers, corresponding directly to the numbered sections. At high altitudes, the readings will be lower, owing to the decrease in atmospheric pressure.

Typical inlet-manifold vacuum-gauge readings and their interpretation

Image

1. An engine in good condition, should give a steady reading of about 17~22 in.Hg. On the whole, the higher the reading the better, but the maximum possible reading for a perfect, run-in engine, will depend on a number of design factors, which include such things as:- valve timing (opening, closing, duration and overlap); plus inlet manifold, air-filter housing and exhaust system flow resistance.

2. Confirmation of good conditon, may be obtained by blipping the throttle, which should result in the reading dropping momentarily to about 2 in.Hg, rising to approximately 25 in Hg and then settling back to 17~22 in.Hg.

3. A steady, higher than normal reading, indicates a clogged air filter element (wire mesh gauze, in an oil-bath air cleaner) or restrictive air-filter housing. How high the reading is, depends upon the degree of restriction or clogging.

4. An obstruction in the exhaust system or a damaged pipe, will give a normal reading on start-up, but will soon drop to 0~5 in.Hg; dependent upon the extent of the damage or obstruction.

5. Air leaks at the inlet manifold, carburettor or throttle body gasket, will result in a steady low reading below 5 in.Hg. How low, is dependent upon the extent of the leak. Exceptionally, a similar effect occurs with a porous inlet manifold casting; a phenomenon which was encountered by an acquaintance of mine.

6. Incorrect valve timing is usually indicated by a steady reading of 8~15 in.Hg. A problem of this type, does not arise spontaneously or progressively, but occurs because a camshaft has been incorrectly installed. Fortunately this problem rarely occurs on air-cooled VW engines, but is more likely on other engines, whose camshafts are belt or chain driven; for which setting the valve timing is more involved.

7. A periodic decrease of 2~5 in.Hg below normal idling vacuum, suggests one or more leaking valves; probably caused by insufficient valve tappet clearances or in extreme cases, valves being burnt. Alternatively, one or more spark plugs may be misfiring.

Decreasing valve-tappet clearances could be caused by valve-seat recession and/or valve-stem stretching; the latter of which, might eventually result in a "dropped valve" and consequent catastrophic damage to the whole engine. Hence, it would be wise to keep a log (a common practice in aeronautics) of measured valve clearances, before & after adjustment (as necessary), at the specified 3,000 mile service intervals.

An irregular, periodic decrease of similar magnitude, indicates a sticking valve or valves. If the introduction of a little penetrating oil (whether this is practical in all cases, is questionable!) into the inlet manifold, appears to temporarily solve the problem, then this is confirmation of sticking valves.

A steady lower than normal reading, of this magnitude, suggests the possibility of retarded ignition, which might be caused by incorrectly set ignition contact breaker points. Alternatively, such a reading might be attributable to worn piston rings; requiring confirmation, as outlined in section 11.

8. Worn valve guides (dependent upon the number of guides which are worn) results in a rapidly vibrating reading of 14~19 in.Hg, which increases in frequency and decreases in amplitude, as one increases engine speed. This condition is one to which the air-cooled VW, flat-four engine, is particularly prone, owing to the lubrication problems associated with the high running temperatures and the almost horizontal valve orientation.

9. The existence of weak valve springs, causes the gauge needle to swing back and forth, when accelerating from idle; the extent of the swing being dependent upon engine speed.

10. A regular swing of the gauge needle, between about 5 in.Hg and 19 in.Hg, would suggest a gasket leak between adjacent cylinders. Given the nature of their construction, this would be virtually impossible with an air-cooled VW engine, but may afflict some others. So far, I have yet to find any documented information about what vacuum readings would result from a leak to the external environment, via the cylinder head to cylinder barrel seal; a condition to which the air-cooled VW engine is prone, particularly if the cylinder heads have distorted, as a result of overheating.

11. A steady reading below normal, suggests either retarded ignition timing (see section 7), or worn piston rings, pistons and/ or cylinder bores. To confirm which, accelerate the engine to about 4000 RPM (for which a rev counter would be useful!), then close the throttle quickly. The gauge should momentarily read about 3~7 in.Hg above the normal; anything lower than this, confirming that worn piston rings, pistons and/or cylinder bores are evident.

Note that 1•0 in.Hg = 25•4 mm.Hg and 1•0 Bar  260 mm.Hg @ standard temperature (mercury – Hg expands with increasing temperature, so the atmospheric air pressure will support a taller mercury column in a Fortin barometer, when the temperature is higher than standard and vice versa)

Note that 30 in.Hg is approximately equivalent to 1•0 Bar; the typical atmospheric pressure at sea level.

Internet link to animated vacuum gauge readings

http://www.therangerstation.com/Magazin ... mLeaks.htm

In the past, when my family’s 1973 VW Type 2 was fitted with the VW 1600 Type 1 style air-cooled engine (awaiting the transplant of a VW 1900 Type 4 style air-cooled engine), a dashboard mounted vacuum gauge, would have been useful, on at least two occasions; once to forewarn me of an increasing problem with worn valve guides and in a separate incident when the ignition timing was becoming progressively more retarded.

In the first case, I had observed a developing problem of crankcase pressurisation (inferred from an increasingly oil-fouled, paper element air filter) and increased oil consumption, despite the maintenance of good cylinder compression pressures. The existence of worn valve guides was finally confirmed, using a hand-held vacuum gauge (i.e. Gunson’s low-gauge). Owing to their effect on inlet manifold vacuum, the worn valve guides, were also adversely affecting vacuum ignition advance, which has a significant influence on fuel economy, under part throttle, cruise conditions.

The other incident arose, whilst on holiday in Northern France, when the ignition contact breaker points’ plastic heel (i.e. cam follower), experienced a high wear rate, owing to roughening of the distributor cam lobes. This resulted in the progressive reduction of the points’ gap and retardation of the static ignition timing, which resulted in a sooty exhaust pipe, plus deteriorating performance and fuel economy.

Had the vehicle not been fitted with an FCD (i.e. frequency controlled dwell) electronic ignition system, the engine would also have started to misfire as the points gap diminished, owing to the reduction in dwell angle. Fortunately, with the FCD system, I could maintain satisfactory performance, by readjusting the points gap and resetting the static ignition timing, on a daily basis, until I had the opportunity to remove the ignition distributor and polish the cam using successively finer grades of ‘wet & dry’ abrasive paper. Why the cam originally became roughened, I never discovered!

_________________
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: Fri Aug 07, 2015 1:37 am 
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Must be something about Vastervik! I was there in 1972 with a nearly new Bedford CF campervan (rented) and the alternator failed. Miraculously there was a Lucas agent in the town at that time who was able to supply me with a new one, albeit at considerably more than UK prices!

Steve

_________________
2 door '73 Toledo with Vauxhall Carlton engine OWF 797M (The Carledo)
Vermillion (and Rust) Sprint Auto EGP 247T (The Dolomega)
'91 Cavalier 2ltr 8v auto
'95 Cavalier 2ltr 16v auto
Spectrum Auto Services, Servicing, Repairs, MOT prep. Apprentice served Triumph Specialist for 40 years and home of Maverick Triumph.PM for more info or quotes.


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PostPosted: Sat Oct 24, 2015 3:10 pm 
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In the following topic thread, "VYO 372M", “NASkeet” & “Carledo”) wrote:

Board index » The Triumph Dolomite Club » Dolomite-related [Start here!] » How far does your anorak zzzzip?

viewtopic.php?f=4&t=4127
Quote:
I have always preferred the early dials to the later type, much nicer visually in my view.
Quote:
I am inclined to agree! I much prefer the earlier style of my 1974 Triumph Toledo instruments, to those of later models. I'm trying to identify a matching rev counter (possibly ex Triumph Spitfire Mk. II, III or IV?); preferably with a few integral warning lights!?!
Quote:
You'll have to get your rev counter from an 1850 Dolomite (early model) to get anything remotely like a match. Spits 1-4 had cable driven rev counters, as did Vitesse and GT6 1 and 2 (but they are 6 pots anyway) Spit 1500 had electric rev counter but it’s the same as late Dolly face.

For my boy's Toledo (project Satin Black) I am using a late Sprint Speedo and rev counter (I'm not allergic to "easiread" dials) matching auxiliary clocks in an aftermarket 3 dial pod atop the dash centre, a la Cortina GT and I bought a handful of marked individual warning lights at Stoneleigh earlier this year which I will mount in the dash in positions yet to be decided but based on ease of visibility. They were only 99p each, it would have been rude not to!
It’s rather disappointing that the tachometers for the Triumph Spitfire Mk. I, II, III & IV and other cars are cable driven, as there appears to be at least one which would be a good match to the style of my 1974 Triumph Toledo speedometer!

I have a full set of instruments (including tachometers, voltmeters, engine-coolant temperature and fuel-level gauges, plus warning-light clusters) from both an early Triumph Dolomite 1850 and a late Triumph Dolomite 1500HL; the latter of which I acquired since laying-up my Toledo in 1999.

When in 1984, I substituted the Triumph Dolomite 1850 dashboard into my Triumph Toledo 1300, I used all of the early Dolomite instruments except for the speedometer; retaining my Toledo speedometer with its three integral warning lights. Sadly the tachometer was non-operational for some reason, despite correctly matching the electrical connections! I had hoped to use this tachometer with a spare indicator needle, substituted from a defunct, early-Toledo speedometer, to closely match the style of my 1974 Toledo speedometer. I also hoped to incorporate into the tachometer, three or more integral warning-light holders, from two defunct early-Toledo speedometers.

I also need to investigate where I can neatly locate some additional gauges (ammeter, oil-pressure gauge, oil-temperature gauge and inlet-manifold vacuum gauge) of complementary style, so that at first glance, they could easily be mistaken for factory-fitted.

Although it’s nice to have a time clock, it’s not essential, so I could use the dashboard aperture to mount a second Lucas 8-segment warning-light cluster.

Noting that the Triumph Stag’s main walnut-veneered instrument-binnacle is configured differently, with the warning-light cluster on the extreme left-hand side, so that it also incorporates a time clock (or substitute gauge), in addition to the speedometer, tachometer, fuel gauge, engine-coolant gauge and voltmeter, I wondered whether a Triumph Stag instrument-binnacle, could be substituted into the Dolomite 1850 or 1500HL dashboard!?!

_________________
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 Mon Nov 09, 2015 4:46 pm, edited 1 time in total.

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PostPosted: Sat Oct 24, 2015 9:00 pm 
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I'm not 100% certain of this, but I THINK the Stag dash is somewhat longer and slightly thinner than a Dolly one, a week or two ago, I could have measured a Stag one for check, sadly the car is now back with it's proud owner.
Since you already have the curved dash, there is not much spare space available for auxiliary instruments. A dashtop binnacle is at least a period fitment, other than that, a binnacle in the Radio space is ok, but means re-siting the radio (or going without), an A post binnacle is too 90s and a roof console, though such things WERE available in the 70s, would have to be bespoke now and done in dash-matching wood for that "original" look.
As a rationalisation, I would draw your attention to the combination oil pressure and (capillary) water temp guage made by Smiths and fitted as standard to MGBs. several other forum members have used these as a way to get an oil pressure guage into a standard dash without sacrificing another instrument (usually the voltmeter).

Steve

_________________
2 door '73 Toledo with Vauxhall Carlton engine OWF 797M (The Carledo)
Vermillion (and Rust) Sprint Auto EGP 247T (The Dolomega)
'91 Cavalier 2ltr 8v auto
'95 Cavalier 2ltr 16v auto
Spectrum Auto Services, Servicing, Repairs, MOT prep. Apprentice served Triumph Specialist for 40 years and home of Maverick Triumph.PM for more info or quotes.


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PostPosted: Mon Oct 26, 2015 6:46 pm 
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Joined: Mon Jan 08, 2007 10:46 pm
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Quote:
I'm not 100% certain of this, but I THINK the Stag dash is somewhat longer and slightly thinner than a Dolly one
It's actually a bit shorter Steve. Height and curvature is the same so it will fit in the gap, but you will have a gap at either end of about an inch - so you would have to make up a couple of inserts/blanking pieces at either end - or do what I did; lop off the end of the Stag dash at the eyeball vent end and then make a new piece to fit and butt up against it (which will also give you the capacity to fit a Dolly eyeball vent rather than the smaller Stag one. I also mounted the fog light switch on this piece rather than below the dash) Gives you effectively a two part dash, but looks reasonably natural, fits the space and gives you the capacity for the extra gauge..


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PostPosted: Mon Oct 26, 2015 9:26 pm 
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Quote:
Quote:
I'm not 100% certain of this, but I THINK the Stag dash is somewhat longer and slightly thinner than a Dolly one
It's actually a bit shorter Steve. Height and curvature is the same so it will fit in the gap, but you will have a gap at either end of about an inch - so you would have to make up a couple of inserts/blanking pieces at either end - or do what I did; lop off the end of the Stag dash at the eyeball vent end and then make a new piece to fit and butt up against it (which will also give you the capacity to fit a Dolly eyeball vent rather than the smaller Stag one. I also mounted the fog light switch on this piece rather than below the dash) Gives you effectively a two part dash, but looks reasonably natural, fits the space and gives you the capacity for the extra gauge..
40 odd years working on Triumphs and I still learn something new every day!
At Stoneliegh yesterday, I saw a couple of late T2000 dashes being sold. These have only 2 large holes (speedo and MFD in the 2k) the warning light "pie" and a couple of small extra warning lights (plus, of course the eyeball vent) Otherwise they are blank, which could let you get creative with the use of space. I have a T2000 here so i'll measure the dash and compare it with a Dolly one to see if it's compatible tomorrow.

Steve

_________________
2 door '73 Toledo with Vauxhall Carlton engine OWF 797M (The Carledo)
Vermillion (and Rust) Sprint Auto EGP 247T (The Dolomega)
'91 Cavalier 2ltr 8v auto
'95 Cavalier 2ltr 16v auto
Spectrum Auto Services, Servicing, Repairs, MOT prep. Apprentice served Triumph Specialist for 40 years and home of Maverick Triumph.PM for more info or quotes.


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PostPosted: Sat Nov 07, 2015 4:21 pm 
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Joined: Tue May 06, 2014 3:38 pm
Posts: 149
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Quote:
Spits 1-4 had cable driven rev counters, as did Vitesse and GT6 1 and 2 (but they are 6 pots anyway) Spit 1500 had electric rev counter but it’s the same as late Dolly face.

For my boy's Toledo (project Satin Black) I am using a late Sprint Speedo and rev counter (I'm not allergic to "easiread" dials)
Given that the Spitfire 1300 and Toledo 1300 engines are both Standard-Triumph A-series engines, I wonder how practical it would be, to adapt my engine to facilitate the use of a Spitfire cable-driven tachometer!?!

Given that the speedometers are driven from the engine’s gearbox via the flexible cable and the speedometer’s calibration is linked to the rear axle’s final-drive-ratio, I wonder how accurate the readings would be, from a Triumph Dolomite Sprint speedometer, installed in a Triumph Toledo 1300!?! Perhaps an “easiread” speedometer with three integral warning lights, originating from a 1975~76 Triumph Toledo 1300 or 1976~82 Triumph Dolomite 1300, might be more appropriate.
Quote:
I'm not 100% certain of this, but I THINK the Stag dash is somewhat longer and slightly thinner than a Dolly one, a week or two ago, I could have measured a Stag one for check, sadly the car is now back with its proud owner.

Since you already have the curved dash, there is not much spare space available for auxiliary instruments. A dashtop binnacle is at least a period fitment, other than that, a binnacle in the Radio space is ok, but means re-siting the radio (or going without), an A-post binnacle is too 90s and a roof console, though such things WERE available in the 70s, would have to be bespoke now and done in dash-matching wood for that "original" look.
Are you speaking of a dashboard-top binnacle (or instrument pod) which is of generic type or one which was specifically designed for mounting on top of the Dolomite HL dashboard?

I have neither seen nor heard of a ceiling console for Toledos or Dolomites, but it might be a viable option if I could find a way to fabricate and mount one, plus concealing the wiring and vacuum-hose connections to it!

I have seen generic A-post instrument pods advertised, plus several for specifically named modern-car models, but I doubt whether are any offered yet, which would be suitable for either a Triumph Toledo-Dolomite or a 1968~79 VW Type 2 van.

When I substituted the early Triumph Dolomite 1850 dashboard, I removed the Triumph Toledo’s centrally mounted, three-piece, black-crackle-finish, sheet-steel, radio-console, with Radiomobile 1070, two-band (Long & Medium wave) mono radio & single speaker with grille (I still have them stored away in my swop box!), which would no longer fit!

http://www.pistonheads.com/gassing/topic.asp?t=867885

http://www.radiomuseum.org/r/radiomobil_1070.html

http://www.vintage-radio.com/manufactur ... annie.html

http://vintagecarradio.co.uk/sales.html

http://wn.com/radiomobile_1070_classic_ ... _connected

http://www.tadpoleradios.co.uk/GalleryRadios.aspx

If I substitute the Triumph Dolomite 1500 HL heater unit, with the additional warm/cold air vent beneath the dashboard centre, there will be relatively little space available for either a radio or supplementary instruments, but I might be able to mount some of my electrical switches and audio C-Boxes there.

If I do decide to retro-fit any substitute in-car-entertainment equipment, it will probably be located beneath the dashboard, on the right-hand side of the substituted Triumph Dolomite HL adjustable steering column. Owing to the presence of the steering-column adjustment locking screw, there is little scope for conveniently mounting accessories on the left-hand side.

I usually tend to listen to recorded music in preference to a radio, so I would probably choose a stereo radio-cassette player; possibly a mid-1980s vintage Blaupunkt Toronto SQR 46 or 48 four-band (Long, Medium & Short wave, plus VHF-FM), four-speaker stereo radio-cassette player, which is what I bought second-hand for my 1973 VW Type 2 campervan; the Short wave facility being useful for BBC World Service broadcasts.

http://retrorides.proboards.com/thread/159490

https://www.youtube.com/watch?v=lSAjZsQlyLc&safe=active

http://www.amazon.co.uk/s/?ie=UTF8&keyw ... l77dxjzj_p

http://www.diagram.com.ua/english/catal ... hp?row=485

Some of my audio cassettes would probably be stored in Tudor C-Boxes (ex Austin Montego | accommodate four audio cassettes | fit into a DIN-E aperture) and/or Fischer or BASF modular C-Boxes, of which I have quite a few in my future-projects’ box.

http://www.fischer-automotive-systems.d ... read-3536/

http://www.motorshop1.co.uk/c_boxes.htm

http://www.ebay.com/sch/sis.html?_nkw=F ... ge-System-

I haven’t made a firm decision about the selection and location of instrumentation, which is something I am still investigating; including the possibility of using instruments originally intended for other vehicle marques & models that utilised Smiths, Jaeger or AC instruments of the same or similar style; my 1974 Triumph Toledo’s original factory-fitted speedometer being an AC instrument.

Ideally, the main walnut-veneered plywood instrument-binnacle should be slightly wider and deeper (i.e. circa 30 mm wider & circa 10~15 mm deeper; especially at the outboard end, close to the circular, cold-air ventilation outlet, which would necessitate a completely different dashboard, but that is not a practical option) to comfortably accommodate my desired instrumentation, including sets of two 2-inch or 2•125-inch gauges arranged vertically.

However, using a full-size paper mock-up of the plywood instrument-binnacle with 104 mm & 56 mm diameter cardboard discs to represent the instrument gauges, I have determined that it might just be practical, to create a new instrument-binnacle, incorporating three 104 mm instruments (i.e. speedometer, tachometer & triple-gauge cluster) and four 56 mm instruments (vertically aligned in groups of two), but there would only be about 5 mm separation, between adjacent instrument bezels. Having this many instruments would be constrained to the following arrangement:

| 1 x 104 mm | 2 x 56 mm | 1 x 104 mm | 2 x 56 mm | 1 x 104 mm |

With this arrangement, the 60 mm diameter, 8-segment warning light cluster would need to be relocated (probably in the time-clock aperture) and there would be little if any room to spare, to incorporate switches or individual warning lights, which would also need to be relocated (in a central console above the gearbox-tunnel or in a supplementary bracket or panel beneath the dashboard, or possibly in the time-clock panel).

Noting that the FWD Triumph 1300 & 1500 and Triumph 2000 featured a four-inch diameter, triple-gauge cluster for coolant temperature, fuel level and either an ammeter or voltmeter, this is one option which might be considered. There also exists a Smiths triple-gauge cluster, which includes an oil-pressure gauge.

Image

I am aware that the FWD Triumph 1300’s ammeter has only a -30~0~30A range, but I envisage that this should be more than adequate for monitoring battery charge & discharge rates; not including starter-motor use. In principle, one could change the ammeter’s range, by substituting a different current-shunt resistor, as covered in GCE “O” Level Physics textbooks.

Quadriple-gauge clusters also exist, but I suspect these are of five-inch diameter, which would be too large. The Morris Minor & Austin/Morris Mini speedometers, with integral fuel gauge and four integral warning lights, would be also be worth considering, but I suspect these are also of five-inch diameter. I am still investigating the possibility of using in my 1973 VW Type 2, a speedometer with integral fuel gauge and seven integral warning lights, originating from a North American specification air-cooled VW Beetle.

Image

Image

_________________
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 Mar 29, 2017 3:37 pm, edited 1 time in total.

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