The Triumph Dolomite Club - Discussion Forum

I'm working on a Sprint that is fitted with a Davis Craig electric water pump. I recently got it running after a long layup and though the pump and electric fan seem to work fine, it is losing water from the bypass tube seals. Oh Cobras, think I, then the light dawns and I think, isn't it normal to blank off the bypass tube when using this setup?
Perhaps someone with more experience of the DC setup could confirm or deny my hunch before I go out and buy more seals!

And as a secondary question, the car has a capillary type temperature guage calibrated in degrees Fahrenheit, the leak is only small so I can top it up and run it up till hot, but what is a sensible "normal" temp reading? the fan comes in about 200 degrees and back out about 190. I know the boiling point of (unpressurised) water is 212 degrees, but everything happens rather too far towards the hot end of the guage for comfort. It doesn't boil and the fan seems reliable. I also appreciate that being stood still (it's not road legal ATM) and lacking a viscous fan it will get hotter than a standard car, I just wondered if anyone else has experience of this type of guage that could give me a guideline!

Cheers, Steve

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'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.
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Not having a mechanical fan should not be a problem. The first thing i do when starting to drive a dolomite is get rid of the thing and fit an electric one. It's so much quieter and the temp better to control. A dolomite doesn't need an mechanical fan while driving and most people know my adventures with these cars to know that they are used under load many times. Never missed one. When someone NEEDS an EXTRA electric fan just find the cause for the overheating.

As for the pump no other experience than theoretical and the bypass needs to be plugged because the thermostat is out. You do not want recirculation in your engine but all through the rad. But if you need a heater in the car you have to buy a remote thermostat, 5 meter extra hoses and a handfull of T-pieces. The best i think is loose the electric pump but if you need one for some reason and fancy a working heater you have to do some plumbing.

Nice article about that here:

viewtopic.php?f=4&t=30938

Jeroen

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If it still has a bypass tube in place then the pump will have had its (already short) life expectancy shortened.
I am off to do a double shift shortly but will try and explain more (with diagrams) about this tomorrow.

Where is the gauge's sender located?



Ian.

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Yes you need the by-pass tube blocked off Steve, otherwise, as stated, the coolant will take the path of least resistance and go mainly straight through the stat housing, through the rad and back through the pump again, thus by-passing the block. I believe some coolant will still find it's way around the block though. The club has the by-pass plugs in stock.

My leccy fan kicks in around 80-85 deg. C. and cuts off around 75 iirc. I have had the temp up to 95 a couple of times.

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1997 TVR Chimaera 450

Steve, I don't know anything about by-pass tubes, but I do have a capillary temp gauge in Fahrenheit in my MGB V8. The car is fitted with a Revotec fan controller and the standard twin fans for an MGB V8. I can set the on - off points for the fan and mine come on when the gauge reads about 210F. If the car is stationary it takes ages for the fans to make a difference to the reading, but then the gauge bulb is in the thermostat housing right on top of the engine, and those V8s get really HOT. My fans switch off when the gauge reads about 190.

During normal driving the gauge sits at about 180 but quickly rises once the car is below 20 mph. In a traffic jam in France in 2015 with outside shade temps of 36C, the gauge rose right past the maximum 230F mark and went into the oil gauge zone (its a dual gauge), but the car didn't boil and didn't display any signs of being distressed, still idling properly. With a 15 lb pressure cap plus 4-Life coolant it is never going to boil until much higher than that.

I understand what you say about everything happening at the top of the gauge scale, and mine is the same. I would say your readings are perfectly OK. Mad Mart posted while I was typing this. I would say that his car's fans are triggering too low. It isn't good to have the car running too cool. I would prefer to have the fans cut off at 85C. You shouldn't worry about getting to 95C - it is nowhere near boiling over, and you might just be getting the engine oil up to a sensible temperature. You need the oil to be at around 90-100C. The MGF/TF has an oil temp gauge and owners are warned not to rev the engine until it registers those sorts of temperature.

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Mike
(1969 MGB GTV8, 1977 Dolomite 1850HL, 1971 MGB roadster now all three on the road)

To check and set fan controllers i use an ir-temp gun. On the china pages these start from around 10 euro incl. p&p. I have a bit more expensive one and did one cheapo compare with mine and the same readings. I do sell these to customers who want to measure the real temp instead of relying on a smiths gauge. When the gauge tells hot it is easy to pop the bonnet and measure it's for real or if you can drive further with no problems.

Jeroen

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Come on Jeroen, get WITH it.
Have a permanent display inside the car from several mounted IR imagers. Got to be a market.

Steve

Where is the capillary sensor mounted ? I have just bought mg dual temperature/oil gauge

Dave

A few extra pointers, the heater is currently blanked off on this car (I intend to replace the entire unit as someone has cut the metal pipes going in and subbed rubber hoses) and I think it still has a thermostat fitted, I will check this at the earliest opportunity. It definitely DOESN'T have the secondary pump for the heater, all the heater hoses and the H pipe are original, as is the rad and expansion bottle.

The guage sender is in the normal position in the thermostat housing.
I think my confusion with the guage is purely personal, normally I think in old measures, inches, feet, pounds (sterling and avoirdupois) gallons, MPG etc. But for temperatures I think in centigrade and Fahrenheit figures are as meaningless to me as litres/100km for fuel consumption!

I think I have the same dual guage as you Bumpa and it would seem from your comments that the figures I am getting are pretty normal or possibly even a tad on the low side. So the system IS working as designed. Certainly, even when the guage is well over and the fan is running, there is no sense that the engine is TOO hot. But I am largely running it with the bonnet up, which no doubt helps with heat dispersal. I am well aware that more modern cars with factory electric fans run much higher average temperatures, my Cav has a 92 degree thermostat and the fan cuts in at 98 degrees and out again at 95. It just seems wrong somehow to indulge in this degree of brinkmanship with a Sprint!
Thanks for all your help so far, keep it coming!

Steve

Just re-read all the comments and thought AH! If I have a bypass tube AND a thermostat, does that make it OK?
A part of me wants to fit the TR7 Sprint heater outlet in the rear of the head, a proper header tank and reorganise the pipework to a more rational setup, the cost conscious part wants to fix the leak and leave well enough alone!

_________________
'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.

Just thought some more and thought "STUPID BOY!" if I have a bypass and a thermostat it will work fine, right up until the stat opens! Then the path of least resistance will take over!
Another thought, what is the difference between a remote thermostat mounted in the top hose and one in the thermostat housing? I appreciate you can't use the stock thermostat (with the "foot") cos the bypass is blanked (or should be), but why not use an "ordinary" non footed 82 degree stat in the stock position? It will fit the space, cost far less in time and effort and hard earned cash than the remote one and surely do the same job?
And do I not also need to relocate the heater return pipe from the original water pump housing to somewhere between the bottom radiator outlet and the EWP to keep it upstream of the pump?

Steve

EDIT, and another question for the fans of the remote stat, wouldn't you need one for EACH of the 2 top hoses? With only one the water would just take the path of least resistance again and run through the second surely?

_________________
'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.

My brain is working OVERTIME tonight - and starting to hurt!

I am now considering how the original "footed" thermostat works and my theory is this, when the engine is cold and the main part of the stat is closed, the foot is raised and the bypass is open. Then when the engine reaches operating temp, the main stat opens which closes the foot blanking the bypass (and thereby the path of least resistance). So I CAN run a bypass and a standard stat! Though I fancy I will still have to relocate the heater return to make the heater work and a proper header tank is not so much more work for a big result.

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.

Steve, i will have your brain hurt more again.

When the original thermostat is closed, how would you have a circulation and even better, how an internal recirculation with an electric pump fitted in the lower radiator hose?

Jeroen

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Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com

Granted, at the moment it's not looking good! Yet somehow it does actually work, perhaps by the archaic and long disused thermic syphon principal! But if you consider the original design, the original pump can only draw water from the bottom hose (as does the DC) and the heater return in the water pump housing. With the stat closed, which blocks off the rad all but a tiny hole in the stat, this effectively limits the circulation to what will go through the heater! And that is stock! If I reposition the heater return below the DC pump, ie in the bottom hose, then I will have recreated the original state of affairs and all should be well. If I then add to that same heater return, a supply from a header tank, the pump can draw from that as well (it will circulate back into the header via the little pipe from the stat housing maybe?) and it will be better than stock! Time will tell! In theory the pump controller only runs the pump in short bursts during warmup anyway, to speed up the warming process, which is a good thing! I can't see that it matters much, how much or little circulation you get during warmup, so long as you get good and even circulation once the engine IS warm!

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.

I am not a graphic designer so please allow for the simple drawings….

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The first point to please bear in mind, a properly plumbed cooling system does NOT need an auxiliary pump.

Pumps have have inlet and outlet sides.

On the mechanical type, the bottom hose, heater hose and bypass tube are all on the inlet side of the water pump cover.

Simply placing an electric pump in the bottom hose doesn't work properly at all,
during warm up you have no circulation of coolant (because the thermostat blocks of the flow to the radiator and therefore pump as well).
The pump relies on having a head of water on its inlet side. without such the pump will run dry, shortening its life.
(The heater and bypass are both on the outlet side!)


The only solution is to fit an inline thermostat and replumb the bypass and heater to the bottom hose (i.e., the inlet side).



In Dolly Mixture there have been two EWP conversions written up.
The problems with both are due to incorrect plumbing installation.
Davies, Craig have a very dubious way of disguising this, namely fitting an auxiliary pump, which disguises the problem
and obviously costs you more as they sell you another over priced product. (You are conned into thinking everything
is okay because the heater is working….)
There are (judging by google) hundreds of slant fours and Stag engines running DC installations
but I cannot accept this is even vaguely right.



There is a decent Electric pump available, but it is not sold in the EU, so has to come from the USA
http://www.stewartcomponents.com/index. ... duct_id=70
however Summit Racing sell them on ebay.


Ian.

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