Lotus Elan

electric water pump

PostPost by: RickPierce » Fri Oct 26, 2007 12:38 am

I need to replace my water pump and am now thinking about using one of the Craig Davies units. Does anyone have any experience with this on a twin cam? I will need to put a new water pump kit in my front cover and was wondering if I should just replace the bearing assembley and leave the impeller off? My existing bearing is shot. I will also be going the Scricco raditor route with the rad as far foward as possible which should help with room for the electric pump. Any thoughts or hints are welcome.
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PostPost by: john.p.clegg » Fri Oct 26, 2007 5:32 am

An electric pump in either the top or bottom hose will circulate the coolant between the radiator and engine,but will not drive any through the heater matrix (or very little) where as the pump where it is uses this route as its first choice,even with the thermostat closed.........

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PostPost by: msd1107 » Fri Oct 26, 2007 7:26 am

Rick,

You are smart and brave. Just remember that either of these modifications takes you away from a stock appearance, which may be of greater or lesser importance to you.

There have been a few posts about the DaviesCraig water pump for the Elan. And several more for other cars. Do a Google search on Davies Craig.

The DaviesCraig website has words about the heater.

And several Elan people have converted to the Sirocco radiator.

You are smart to position the radiator as far forward as possible. Depending on how the components are placed in the nose of your car, it is possible to position the radiator completely to the front of the car and leaning forward. That way, the intake air goes immediately through the radiator, rather than tumbling in a turbulent manner through the nose to the current radiator position, where the air flow is not used very efficiently.

Then you have to deal with the airflow from the radiator. There are several posts from people with different solutions, ranging from holes in the front wheel wells (the maintenance manual deals with that), to ducts at the rear of the hood (a couple of illustrations of that), to letting the hood raise proud at the rear (an ad hoc solution often used by vintage racers), to vents on the side of the hood, to vents in front of the hood (like some mod sports cars).

Each of these has its advantages and disadvantages, especially when it comes to retaining a completely stock appearance.

One of the interesting side effects of the electric water pump is the fact that you will gain a little better acceleration since the water pump is not absorbing power at all times and the electric water pump only runs when necessary.

There is a post that allows you to model the effects of the electric water pump.

http://www.lotuselan.net/forums/viewtopic.php?t=15596

What ever you do, enjoy the results.

David
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PostPost by: John Larkin » Fri Oct 26, 2007 7:45 am

Dear Rick,

I have a Craig Davies electric water pump in my S3, in conjunction with an electric fan in front of the radiator. I retained the original radiator. I have left the original water pump and two-bladed fan in place undriven, and use a shorter belt driving only the alternator.

I mounted the electric pump in front of the radiator at the right, so the pump is in the lower radiator hose. I have use a combination of connectors and silicon hoses to make a loop that passes from behind the radiator forward to the new pump and then back again to the engine. I was able to route one leg of the hose underneath the large blank plate that forms the right-hand side of my radiator, but the other leg needed a large hole drilled in that plate.

In the parking lot driving environment that prosperity has brought to Dublin I had a real problem with overheating while stopped at traffic lights. Even in winter the temperature needle could be seen moving higher at idle, and in summer the rate of rise was alarming. The best I could do was rev the engine to about 1500 RPM in neutral to maintain high water pump and fan speeds. The car was becoming a worry and a chore to drive.

I use the electronic thermostatic control option with the water pump and also with the fan. I now no longer fear driving the car. I have set the water pump on temperature at 90 Celsius and enjoy watching the needle reach that temperature, stopping there, and then dropping back to 87ish as soon as the pump kicks in. I recommend the electric pump if you drive at all in stop/start traffic. It has been in the car three years now.

I have not experienced any problems with the heater --- in fact I think that it is working better. I don't understand why re-locating the pump would affect coolant flow rate to the heater as John as said, but maybe I have just been lucky.

John Larkin
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PostPost by: alaric » Fri Oct 26, 2007 4:27 pm

John that sounds excellent. I would be interested in part numbers etc. I was wondering if the electric pump avoids the need to fit a bigger rad if the standard one is ok at driving speeds. Did you remove the wax based thermostat or is that ok left in place - presumably with the standard water pump disabled you need some circulation of water all the time from the electric pump?

If you've any photos that would be of interest.

Sean.
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PostPost by: daves56 » Fri Oct 26, 2007 5:04 pm

I also have an electric water pump in mine. I believe it is a Jabsco, about a 6 GPM, I don't have a thermostat or any electronics hooked up. Just a relay so it turns on after the engine starts. This is also connected to the lower hose and I have no problem with the heater working. If you have problems with the engine overheating you will love an electric pump. I struggled for years trying to cool off the engine. I recored the radiator to a four row. I ventilated the engine bay. I tried water wetter. Now my biggest problem is warming the engine up. I also removed the stock water pump, made a small aluminum plug on the lathe and fitted that.
Another concern is an electric pump will draw a lot of current. You may need to update your charging system.
Good Luck,
Dave S.
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PostPost by: RickPierce » Fri Oct 26, 2007 5:13 pm

Everyone thanks for the input,John I could leave my old pump and run the belt as you described I was worried the impeller might impede the water flow.However as Sean pointed out pics would be great.
Rick
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PostPost by: RickPierce » Fri Oct 26, 2007 5:16 pm

John which model water pump did you use?
Rick
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PostPost by: John Larkin » Fri Oct 26, 2007 7:11 pm

I used a Davies Craig EWP 80 in conjunction with the electronic controller that is available separately from the same manufacturer. Davies Craig have a website which lists suppliers around the world.

I removed the original thermostat.

If I can find out how to post photos I will do so.

John Larkin
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PostPost by: John Larkin » Fri Oct 26, 2007 7:29 pm

Photos of electric water pump....

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DSCN0014R3.jpg and
Picture 2
DSCN0013R3.jpg and
Picture 1
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PostPost by: alaric » Fri Oct 26, 2007 7:41 pm

I've just been onto the Davies Craig website looking at their electric water pumps, and from there onto Demontweeks. Looks like a neat solution especially with the digital controller.

A link for a price is: http://modifying.demon-tweeks.co.uk/pro ... cls=MSPORT.

Looks like the temperature sensor can be fitted into the top of the thermostat housing.

I've just seen the photos - thanks John - I'm now very tempted - looks like a very neat installation using standard hoses cut to length.

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PostPost by: rodney » Mon Oct 29, 2007 9:42 am

I have had 2 davies craig water pumps in my elan over the last 5 years. The seals wore out on both and I am now on my third. The latest model has a ceramic seal like normal waterpumps so I am hoping this one will last a bit longer.

I was not having any overheating problems as I fitted a Davies Craig fan, thermostat and pressurised overflow bottle over 15 years ago. The reason was that my water pump was showing signs of leaking. So I removed the pulley to the water pump and fitted the EWP80 with my own electronic controller. The Davies Craig controller was way too expensive, 1.5 times that of the pump. They say that you can run the pump without the controller.

I fitted mine between the radiator and the webers as shown in the attached photo. The hoses were off a single top radiator hose for a Holden Commador (Australian) but I would think that there are others that would do the same job.

The heater problem is caused by 2 things 1. the pump pumps water from the radiator through the heater not hot water from the head. The only pressure available to drive water through the heater is the difference in pressure from the water inlet to the water outlet at the thermistat which with a clean block is not that great.

Anyway I think it is definately worth the trouble of fitting and I haven't had to remove my head to replace the pump for 5 years now.

Rod
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EWP 80 installation
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PostPost by: John Larkin » Mon Oct 29, 2007 10:20 am

The Davies Craig pump in my car is the second one that I fitted. The first one had a seal failure similarly to Rod's experience, and this apparently caused the pump motor to become saturated with water. I had bought the pump two years prior to installing it, and it was one of the early types. It failed after 1134 miles and 25 hours running, two years after expiration of the warranty.

I bought another pump anyway as I was impressed by the device, and put the failure down to chance. I wrote to Davies Craig explaining what had happened offering to return the failed unit at my own expense for their R&D department to do a post-mortem and improve their product. Unexpectedly, and to their credit they sent me a new pump (by Fedex from Australia!) as they considered that the spirit of the warranty still applied despite the age of the pump.

I'm impressed with Davies Craig's pride in their product!

John Larkin
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PostPost by: Petter Hval » Mon Oct 29, 2007 10:11 pm

Rick
You`ll also need a T- pice between the rad. and the pump,
(the suction side of the pump) which should be connected
to the r.h.s heater hose if you have a heater in the car.
Petter
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PostPost by: Mr.Gale » Tue May 30, 2017 8:35 pm

I know this is a very old thread but the pump on my car is starting to go bad so I'm looking at different options and the EWP looks interesting. What I would like are updates to this thread from those who have made the conversion. I also have a couple of questions; first, do you have to remove the impeller? and second, what size of fan for a stock S1 rad.
Thanks,
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