Electric water pumps.

[History]

I have been checking out electric water pumps.
Triumph Stag engines have a water pump that is at the top of the engine, which runs dry at the first sign of coolant loss. Not a good design.
A solution is to fit and electric water pump at about crankshaft level. The thermostat is best removed and the water pump used for temperature control via a thermostatic switch. Similar to an electric cooling fan.

Bob.

[JPB]

Bob, No! The Stag (and Saab 99, Dolomite and TR7 that have the smaller versions of the modular Ricardo engine) water pump isn't at the top of the engine, it's on top of the crankcase but the radiator, the head(s) and all of the coolant in the inlet manifold, the heater and the header tank are higher and most failures of pumps on these are caused either by a worn jackshaft bush at the rear of the block or leaking into the sump from the water pump from its graphite seal above the gear that's driven from the jackshaft. EWPs mask the symptom that could have been dealt with more effectively by drilling out the bush at the back of the block and running the shaft in bearings instead.
I'd always be suspicious of any engine of this type that had an EWP conversion, usually because it may simply mean that changing the pump impeller, setting its height by using the appropriate shims or avoiding damage to the brass cage on the way out have been beyond the person doing the job. Some folk can't decide between six or twelve, but Saabs used eight vane pumps that would be way above poncy EWPs on the list of things to try!

And the thermostat is critical in these too, the issue there is that some folk fit one without a foot that closes off the feed from the pump but please, if you must run any engine without the 'stat, don't let it be one of these!

[History]

Never worked on a Stag engine. Apart from service work. The Stag looked good but I found them not a fast car.

My car has a bypass that must be closed when the stat opens else coolant takes the shortest route. In the UK temps its generally thought that one will get away with it. But I carry a bit of turned down broom handle which fits the bypass should it be necessary to get home with a failed stat removed. The designers of my cooling system are experts in cooling piston engines. The water pump is slightly below the bottom of the cooling jacket. The radiator has a separate header tank which has a quaintly named steam valve. The radiator is vertical and is wholly filled with coolant. This engine was tested in death valley and it doesn't overheat. Servicing required though once in a while. The later versions post 1980 changed which wasn't as good then in 1990 the system reverted back to the same as mine except plastic bits. Mine is made of brass and copper.

The stag water pump is to me too high on the engine and appears to be above the coolant jacket. The radiator top may be higher but the water pump layout is a mess. Much too complicated. The Rover engine has a water pump in the normal place and fits so why Truimph chose this design is a bit of mystery.

Ideally if using a EWP I would remove the water pump entirely. Block off the bypass. Remove stat. Vary the water pump speed to control temperature. Also run pump after engine shut down to offset any heat soak. Especially if linked to electric cooling fan. BMW and Merc.

The fans of EWP quote up to 10% fuel saving but they tend to overestimate how much power a belt driven pump uses. I have seen as much as 20hp quoted. I reckon about 3hp for my car 6750cc. There is a big fan which is a separate issue and uses a fair bit again often over estimated. I think there are some power saving to be had with EWPs but is probably many many miles before the cost is repaid if ever

.My understanding of Stag cooling problems are pump too high, poor casting of some heads and no corrosion inhibitors being used. The head problem has been solved because the duff ones have gradually been scrapped. The coolant problem has been solved by owner awareness. This leaves the water pump position.

This is all hypothetical to me because to me the best way to sort a Stag is a Rover engine. Although the power outputs are similiar the Rover has more torque. And before someone says the Stag engine can be tuned to give more power so can the Rover and the Rover will win a tuning war for less money.

Does a GM 350 small block fit.

Bob

[JPB]

Never worked on a Stag engine.....

Then please don't be led by the urban myths surrounding this and the single bank versions found in the Saabs and smaller Triumphs. The pump is no higher than many of the pumps found in the more conventional position on most other engines and isn't in itself cause for concern as long as any work in that area has been carried out by someone who has kept abreast of the solutions that have come along with the passing of time. The real issue with both the V8s and the slant 4s was that the workforce were more used to assembling and working with cast iron engines that were much more tolerant of Friday afternoon syndrome.
Had the Ricardo/Stanpart/Saab engines been assembled and their materials QAs been carried out by the engineers at Saab, rather than their fitting together already compromised parts, things may have been very different, Saab's solution was to redesign the head fastenings for their own development of the 2 litre slant, they placed the studs and the bolts all perpendicular to the face of the block, which meant that a conventional tightening pattern could be used, so eliminating the issues arising from people who'd assumed that these things should have been tightened down in the more usual way; side to side as well as front to back along each row when in fact this caused the heads to warp and also meant that it would be impossible to prevent one row shuffling about in use, easily solved by doing the job properly as indeed it was in the majority of units but time doesn't remember the good ones as that wouldn't appeal to the purveyors of the myths!

[rich.]

of course the best answer is to fit the rover v8..

[JPB]

of course the best answer is to fit the rover v8..

F}[[]{[¾ off!

There's nowt wrong with a nice Rover engine, but anyone who's driven a Stag with its correct engine would tell you that, short of fitting something Italian, there's nothing close to the soundtrack of the original, OHC V8 when it's being thrashed to its red line.

[suffolkpete]

And a Rover engine, even if the conversion is done properly, will knock thousands of the value of the car, and so few of these engine swaps are done properly, so the owners are forever tinkering with them.

[JPB]

...so few of these engine swaps are done properly

True, but there are some good ones. Sadly, the good conversions aren't very interesting and they're not even a little amusing. A really badly lashed up RV8 conversion, however, is right up there with the worst disasters ever when it comes to entertainment value.

However, if you want to do the job neatly and just can't stand the idea of using a relatively crude, pushrod V8 that doesn't weigh enough, Toyota to the rescue with this conversion from the Untied States:



I'm thinking that the diff, driveshaft joints and rear tyres may be the bottleneck in that one though.

[rich.]

of course the best answer is to fit the rover v8..

F}[[]{[¾ off!

There's nowt wrong with a nice Rover engine, but anyone who's driven a Stag with its correct engine would tell you that, short of fitting something Italian, there's nothing close to the soundtrack of the original, OHC V8 when it's being thrashed to its red line.

rover v8s sound rather nice too!!!
i cant get your linky thing to work john

[JPB]

Fixed that now, Rich. (I NEVER use my Bhotophucket account, ever, but that's where the piccies of this car are stored for some reason. Bhotophucket is rubbish, and images hosted there never work straight away as flickR ones do..)