Electric Cooling System Water Pump!!!

[az88turbo]

Hi All,

After taking apart my water pump for the third time in about 6 months, I decided to look for an alternative. I came across the following EWP on the web and I think it is exactly what I have been looking for: www.daviescraig.com.au/ and take a look at an independent review: www.fordmuscle.com/archives/2000/08/electricwaterpump/index.shtml

I think I am going to block up my mechanical water pump and fit one of these puppies in a place that is easy to get at (he says looking down at the cuts and scratches on his hands and arms from reaching in to the engine bay to get at the water pump). I am also going to fit an electric vacuum pump (as it only drives the breaks since I did the TEC3 ECU and fuel injection system conversion) so I can get rid of the “crank, water-pump – vacuum pump V belt” completely).

Looking for any opinions/comments from you folks. Also figured I would post it in case anyone else is interested in this type of conversion.

What do you folks think?

Cheers,

Mark

[GreenV8S]

I've added one of these to the V8S. After carefull investigation I decided that it wasn't anything like powerfull enough to completely replace the mechanical pump on the V8 (despite what you'll hear from DC), but its a usefull booster pump. It might be enough on its own for smaller cars, I guess it depends how much power (and hence heat) you're dealing with. It's been discussed elsewhere on PH so a search should show up some relevant discussions.

[lotusguy]

Mark,

Not enough capacity for anything but a booster or chargecooler pump. Back on the electric vac pump eh..?? Sounds like you're trying to either eek out a few more HP (approx. 3-4) by eliminating the draw on the crank, or set-up the engine to run at higher RPMs.

Faulty reasoning! Adding these kinds of loads to the alternator will cause it to rob much more crank HP than these accessories would draw themselves. The very best alternators, in terms of efficiency (which the Esprit is not equipped with) convert only 35% of the mechanical power they draw into usable electricity, on top of that, add the inefficiencies of the new water and vac pumps and there's no gain to be had at all.

As far as running higher RPMs, the engine will go to about 9k RPM before you start getting into trouble w/ valvetrain components, the 7200 RPM 'RedLine' is governed mostly by the ancillaries, however, there is little additional HP to be had from operating in these nether regions, but many potential pitfalls.

Why is it your waterpump keeps failing? There has got to be a reason. Are you rebuilding it yourself? If not, does the tech know what they're doing? There are several critical procedures which must be followed as well as several critical measurements which must be transferred from the original pump, including impellor and pulley offset. Also, all pressing must be done with the pump housing properly supported and the pressing done on the outer race of the bearing/shaft. Finally, the seal face must be lubricated, preferably w/ silicon grease prior to assembly to prevent a dry start-up. Failure to observe any of these can lead to premature failure. If properly rebuilt, one can reasonably expect 50k-60k from the 'new' pump, many go even longer.

I have rebuilt several of these and never had a failure, just did one last week as a matter of fact for a '77 S1, have a '79 S2 in the wings waiting to be done as well. Let me know if I can help. Happy Motoring!...Jim'85TE



>> Edited by lotusguy on Friday 28th November 06:35

[AZ88Turbo]

lotusguy said:

Mark, Not enough capacity for anything but a booster or chargecooler pump. Back on the electric vac pump eh..?? Sounds like you're trying to either eek out a few more HP (approx. 3-4) by eliminating the draw on the crank, or set-up the engine to run at higher RPMs. Faulty reasoning! Adding these kinds of loads to the alternator will cause it to rob much more crank HP than these accessories would draw themselves. The very best alternators, in terms of efficiency (which the Esprit is not equipped with) convert only 35% of the mechanical power they draw into usable electricity, on top of that, add the inefficiencies of the new water and vac pumps and there's no gain to be had at all. As far as running higher RPMs, the engine will go to about 9k RPM before you start getting into trouble w/ valvetrain components, the 7200 RPM 'RedLine' is governed mostly by the ancillaries, however, there is little additional HP to be had from operating in these nether regions, but many potential pitfalls. Why is it your waterpump keeps failing? There has got to be a reason. Are you rebuilding it yourself? If not, does the tech know what they're doing? There are several critical procedures which must be followed as well as several critical measurements which must be transferred from the original pump, including impellor and pulley offset. Also, all pressing must be done with the pump housing properly supported and the pressing done on the outer race of the bearing/shaft. Finally, the seal face must be lubricated, preferably w/ silicon grease prior to assembly to prevent a dry start-up. Failure to observe any of these can lead to premature failure. If properly rebuilt, one can reasonably expect 50k-60k from the 'new' pump, many go even longer. I have rebuilt several of these and never had a failure, just did one last week as a matter of fact for a '77 S1, have a '79 S2 in the wings waiting to be done as well. Let me know if I can help. Happy Motoring!...Jim'85TE >> Edited by lotusguy on Friday 28th November 06:35

Hey Jim,

I'm not looking for any more HP (think I have enough with the mods I have made now), just fed up of the water-pump letting me down. This is the 3rd time in 6 months and the thing is just a pain to get at. It has been rebuilt twice by a certified Lotus mechanic, by the sound of things he can't be doing it right can he? I was going to do it myself this time but looking at the seal; it just doesn't look that clever to me (not that I am any expert). The trouble I am having is that the seal breaks (not sure if it is the plastic or the ceramic bit that breaks first) and all of the water in the cooling system just evacuates in about a minute flat. It always seems to do it when I am at a fairly high speed (not excessive, about 80mph this time) and by the time I notice it my head is fried. I have a feeling that my head is going to be warped again (after the recent last rebuild, I am obviously not too happy at all about this), the car has been on the road for 1 day in the last 2 months and it is all due to the bloody water pump. So, there is a long-winded version of my reasoning for looking at the EWP.

I figured that 1300 gallons per hour was plenty, and 7.5 amps max pull is not that much at all. There are plenty of people on the web that have used them and sing there praises. But, not with a Lotus that I can find yet.

Any idea how many GPH the stock water pump will pull? The folks on the evaluation say that it was plenty to cool a 5.0 Mustang, do we need more cooling power than that? Perhaps so because of the extra heat from the turbo? A lot of people in the racing world seem to use them on 700hp+ racing cars.

The vacuum thing is just to get it out of the way as I said, I can't see that giving much more HP.

Not sure where the RPM discussion came from, I certainly wouldn't like to hear my 4 banger rev any higher, sounds like it's going to blow up at 7k.

Thanks for the input folks, guess I'll have to take another look and do some more research. Or find someone here locally who knows what the heck they are doing when rebuilding water-pumps. I guess when it comes down to it I would rather get the OEM pump rebuilt again if I could be sure that I wouldn’t be taking it out again in a couple of weeks.

Cheers,

Mark


>> Edited by AZ88Turbo on Friday 28th November 10:26

[dr.hess]

Hey Mark,
From a thermodynamic viewpoint, I don't agree with electric waterpumps, but from a PITA viewpoint, they may work out for you. You need to consider what the HP they will cool is. If they cool 700 HP motors, for how long? Long enough to idle waiting for the lights to change and then 1/4 mile down the strip or long enough to drive from Arkansas to L.A.? Also, that 1300GPH is probably rated at 0 head pressure. You add head pressure like from a radiator, 20 ft of tubing, a head and block and that 1300GPH may drop to 300GPH, which might or might not be fine. Don't know. You are just going to have to put it on and see. Don't blame you for wanting to dump the mechanical one given the problems you have experienced. Also, water pump failures such as you are experiencing do not seem to be common with these motors, unlike the TC motor (don't get me started). So, you may have some other issue taking it out, such as a mis-aligned pulley/pump, bearing in the pump, pump caseing warped, overly tight belt, etc. I would at a minimum start with a complete new (or new to you) pump this time if you do go mechanical again.

BTW, there is a head on eBay right now. Not complete, but with the pieces from your head, you may be able to make one good one from the two.

Dr.Hess

[GreenV8S]

What I found for my RV8, is that the water pump is able to flow enough to control the average engine temperature, but not enough to control the temperature gradients in the cylinder head under sustained load. The engine may not actually overheat, but you can still ruin the durability of the cylinder head. The mechanical pump draws about 3KW, it's relatively small for this type of engine although being connected to the engine it has loads of torque available and will keep the flow rate up even if there is significant back pressure. The electric pump draws about 0.1KW, against zero back pressure it will flow about half what the mechnical pump flows but this drops off sharply when you add back pressure. Electric motors and centrefugal pumps aren't a happy combination because the motor has to slow down to generate torque but the pump gets less effective the slower it goes.