My Dolly Sprint had a Davis Craig pump and I know of many Stag owners who had a DC pump installed. In principle they are a superb idea, but they are not without their issues.
Let's start with the good stuff
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Firstly it should be said that my Dolly Sprint had fresh coolant and a recored radiator and new fan coupling courtesy of the previous owner, trying to 'cure' it overheating. It probably did help things for the better it has to be said. With that groundwork out of the way.
-I liked how with the controller the speed of the pump varied. It initially pulses the pump at 6V and only when it is hot will the pump run flat out at 12V. Of course it varies itself more than this elsewere.
-The controller also being able to run a cooling fan (via an additional relay) is also a great touch IMHO.
-The controller allows the pump to run 5 minutes after the car has shut off, thus reducing heatsoak.
-In working order my car never overheated and that was without an electrical fan during the summer.
-The controller has a temperature gauge which seems to be accurate when I last checked it.
-Bleeding the cooling system is theoretically easier with the pump being mounted lower down.
-Less stress on the Jackshaft - it is driving one less thing
-If the Jackshaft is slightly worn on the water pump teeth it is potentially a way around it.
Now for the not so great:
-The controller for sale now is quite different to what was offered before and is far more flexible. However, a known Stag owner found that his temperature gauge will swing between 1/4 to half way without a thermostat in place. However, the thermostat gave him other issues (DC say that you should not run a thermostat). In the end I think he installed the shell of the thermostat to keep things good. TBH mine used to go between a 1/3rd on the temp gauge to halfway. It never went beyond halfway however.
-It takes up more space. I seem to recall that adjusting my throttle cable was trickier. But I managed. This is a small point TBH
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-You HAVE to add hardware to the engine. Failure to do so can bring about disaster. The main bit of hardware that has to be installed is the water pump bung. Without this the oil will mix with the water with obvious results. The other part of hardware that needs installing is the bypass blank off. With no thermostat the bypass still being plugged in will potentially cause overheating since water that has 'bypassed' the radiator (i.e Hot coolant) will go straight back into the engine. I have seen a few converted without the bypass being blocked which IMO is laughable on a car known for overheating.
-Controller faliure. When I bought my Sprint the controller was a duffer. It failed into a failsafe mode which ran the water pump at max power all of the time. Motorway trips were fun with the choke being out. However, I understand such failures are rare (rarer than Jackshaft issues in the Triumph Slant 4s and V8s) so that is open to interpretation. To be far to DC they replaced my controller
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-Price - I'd say you're looking at £400-500 to convert your car correctly to run the Davis Craig pump and controller setup and a good few hours work. In theory it should not need touching again mind you.
I probably have put out the conversion to be poor but it is not IMO. I however figured that there is no point in sugarcoating what one may face.
Saying that, the stock pump on my Stag was fine and on a friend's Dolomite Sprint. They do have to be fitted correctly however which many years ago many were not. Plenty of people used the thicker gasket in water pump kits without thinking why 3 gaskets were applied in the first place.
However, a worn Jackshaft is a game changer. My Sprint did have worn teeth on the jackshaft however, hence why the car went to a DC EWP conversion.
I do wonder if the Steve Bull 'Stagdad' Ford Capri water pump conversion could be adapted without much trouble however. This conversion is very sucessful in the Stag world with many owners swearing by it. Steve would be the man to speak to however.
Here is my old thread
:http://retrorides.proboards.com/thread/133516/1979-triumph-dolomite-sprint
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