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Electric water pumps

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Fossil
Posts: 442
Joined: Sat Feb 13, 2016 5:08 pm
Location: Helensburgh, Argyll

Electric water pumps

Post by Fossil »

Hello gentlepeople

A penny for your thoughts

We hear of the increasing use of electric water pumps in modern car engines, esp those of the racing fraternity. They are also mentioned with regard to older engines as a means of improving cooling system function and reducing problems, in addition to the possible release of additional power from the engine.

It has occurred to me that such a mod might be beneficial to the 4.5 engine of my SP'450', which in the past has been prone to cooling issues. The engine itself and cooling system are sound.

I'm no expert but it seems that the principal complete option to install an electric pump in an older car appears to be to remove the pump impeller and run the electric pump as the sole source of circulation while retaining the pump pulley to drive the fan, or perhaps taking the pump pulley out of circuit by means of a shorter fan belt, in which case the impeller still needs to be removed, but the standard fan becomes redundant and should be removed also, thereby necessitating an electric rad fan.

Now the car does already have twin electric rad fans in addition to the standard fan, and I'd quite like to retain the latter. Improving fuel economy isn't near the top of my list of aims, and being naturally inclined to avoid unnecessary effort I do wonder whether it might be possible to fit an electric pump in the bottom rad hose without removing the standard impeller from the pump.

So that is my question with apologies if it is sounds totally stupid: might it be possible to fit an electric fan in the bottom rad hose so that it could be operated to supplement the standard pump with the engine running and also after it is switched off, to reduce the possibilty of hot spots and so on. And, would there be significant problems if the engine ran with the electric pump off?

Perhaps I should speak to an expert, but I wondered if a simple answer would be obtainable from among the many knowledgeable members of this Forum. To go further is there a specific electric pump that anyone might recommend for such a purpose?

With thanks for your thoughts and/or suggestions.

Regards

Fossil

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JohnM
Posts: 117
Joined: Thu Feb 11, 2016 1:31 pm
Location: N W London

Re: Electric water pumps

Post by JohnM »

Hi Geoff,
EWP's are a great idea I think - I've recently helped fit one to a GT40 replica to overcome space issues (the standard pump sticks through the seat bulkhead!) and to a Jensen Interceptor. In both cases we used the recommended "bottom hose" location. They work very well in combination with their variable speed temperature controllers, and you can wire them to keep running when the engine is shut down so you don't get that annoying heat dump we all know so well on the SP's.

The pumps we used came from this range: (the "Gold Standard" I think)
https://daviescraig.com.au/electric-water-pumps

and the GT40 one was sourced from
https://www.carbuilder.com/uk/water-pumps

who do a range of EWP's including booster pumps. I think the Jensen one may have come via the Club, so I can't give you a link for that.

Your minimum effort direction might well be to fit a booster pump with a temperature controller in an available hose, maybe a heater hose? A booster pump with a big enough diameter outlet to fit your bottom hose might as well be the main pump, I'd have thought..........

Just my views, of course, but I hope it might give you some interesting reading and ideas!

regards ,
John
John M in Middlesex, NW London
1962 SP250 "B" Spec

classiclife
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Re: Electric water pumps

Post by classiclife »

Fossil wrote:
Tue Mar 17, 2020 9:19 pm
It has occurred to me that such a mod might be beneficial to the 4.5 engine of my SP'450', which in the past has been prone to cooling issues. The engine itself and cooling system are sound.
Hello Fossil,

Can you expand on the above, please ?? If the engine and cooling system is fine and behaving properly I am not sure what extra you are trying to achieve as your car is well equipped with both types of fans.

If your current water pump is doing what it should, then I think this extra cost will not provide any further benefit to you.

Regards.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Area Representative.

Southern Classics Society Events Co-ordinator.
www.southernclassics.org.uk

Ian Slade
Posts: 517
Joined: Sat Feb 13, 2016 9:54 am
Location: Akrotiri Cyprus

Re: Electric water pumps

Post by Ian Slade »

Hi Geoff, the SP waterpump is not the most enfficient, so I doubt the Majestic Major pump is any better, much depends on the clearance between the casing and the impeller, it would seem that cavitation can occur, the first indication is when changing a water pump on failure the new one fails to run the heater, though the pipes are hot when the heater is turned on only cool air is available due to the pump not producing enough flow through the matrix. There is a fairly cheap infrared thermometer available on ebay or Amazon, possibly even Screwfix, by pointing this at various locations arround the engine and cooling system hot and cool areas can be pinpointed and rectified, assuming there is a blockage or restriction to flow. There is one version that can be used with a smart phone.
I am returning to Scotland today for a few weeks so Covid19 restriction contraints we can have a chat
Owner since the 70's, Genghis is slightly to my left.

DAMEEDNA
Posts: 4
Joined: Wed Feb 17, 2016 8:51 am

Re: Electric water pumps

Post by DAMEEDNA »

I fitted the Craig Davis electric fan with two fans around 4 years ago, I manually switch the “ second” fan which I activate prior to stop start in heavy traffic or mountain climbing.
I live in central Queensland where the temperature is regularly 35+ degrees.
I simply manufactured a blanking plate and fitted it over the original water pump mounting and fitted the electric pump in the lower hose.
I am extremely happy with the performance of this set up, the pump acts as a thermostat, fans activate automatically as required and will keep running and circulating coolant after shutting the engine down.

Trevor A

Fossil
Posts: 442
Joined: Sat Feb 13, 2016 5:08 pm
Location: Helensburgh, Argyll

Re: Electric water pumps

Post by Fossil »

John, Richard, Ian and Trevor

Thank you all ++++ for your thoughts and helpful suggestions; apologies for my slow response, even in self-isolation the routine requirements of life seem to take a significant amount of time to accomplish. Coupled with the speed at which time is passing, I assume that this all has something to do with now being over 70 and I by inclination not being an early bird!

Apologies for my 'deliberate' mistake, I of course meant fitting an electric pump in the bottom rad hose, not an electric fan! But a difficult mistake to avoid. Perhaps EWP is the best term. John, thank you for your links and thoughts, I appreciate the opportunity to visit the Davies Craig website, very helpful. I'll return to that without doubt.

Richard, I appreciate you common sense perspective.

Ian, delighted to hear from you, as always! Your experience of the SP is unsurpassed and any thoughts are welcome. I'd be delighted to see you again when you're in Scotland if you can get here? Perhaps coffee here at suitable 'social distance' in the absence of bars and restaurants? We can email directly?

Trevor, I appreciate your experience with the Davies Craig pump.

There are two issues that I need to think through, the car having been immobile and the engine not run for some years while I try to move on with its comprehensive recommissioning (the whole exercise being unfortunately at the very bottom of any and every priority list) :

The first is the health of the cooling system, the second is the question of underbonnet heat at rest, and 'the third', if it exists, is whether there is any likely connection between the two.

First, from memory the cooling system is sound, so I have little doubt that the engine will continue to function adequately while on the move, and while at rest if the elec fans function well. My interest in the EWP was primarily around the possibility of improving engine cooling specifically by supplementing the standard water pump, not yet by replacing it, although the latter option remains available if required. The radiator is non-standard, possibly a custom-made unit, the core is 3" wider than the standard rad, same height and depth but vertical flow with a large header tank. It did cope with keeping the engine temp satisfactory at rest provided the fans were switched on before movement ceased. The standard fan was not fitted but came with the car, I don't know why. The water pump is from a MM but fitted in/on to a modified SP water inlet pipe, (the water outlet pipe/thermostat housing is also SP), it did all seem to work adequately, and in absolute terms the equivalent MM items are just of different shape but not size. There is space to fit a MM rad fan to the water pump even though it is offset to the offside.

The second question is the most immediate from memory. There isn't a problem when the car is in motion. For those who have read my description of it in the 'Driving Member', the movement of the engine rearwards and the grafting on of the Jag MkII front suspension subframe has created a large space in front of the engine which is open to the elements below and on either side. As a result there is a distance of about 4 to 5 inches between the fan and the radiator, and at rest the fan will possibly not draw enough air through the rad, hence the elec fans, but it will create some cool air flow around the engine, drawing air in from below, which is why I'd like to retain it. Engine heat escapes to the rear in the usual way, mostly to the sides and below the engine, but also via the scuttle grille which is open to the engine bay due to the removal of the heater box. I may give some thought to finding other outlets for engine heat: there were formerly two unsightly round vents in the bonnet, which have been glassed in at some point, and the bonnet hinges are lifted on aluminium blocks at their point of attachment by 1" to create space for air to exit at the back of the bonnet, but this too looks very poor. Perhaps a pair of large aluminium louvred panels in the bonnet would look nicer as well as being more effective, or a complete aluminium bonnet with many louvres a la E Type, or no bonnet at all a la US Hot Rod (joking!).

But to cut to the chase, It appears that just fitting a full function EWP in the bottom hose would not be feasible just to supplement the standard pump from time to time, so I'm discarding that option. I've not been able to imagine how to supplement coolant circulation through the block and heads via the inlet manifold system flow (the heater has been deleted), so retaining the standard pump and rad fan seems the best option at least until the car is back on the road and the various functions and circumstances can be evaluated directly, so there we go.

Thanks again to all for your help, now wash your hands!

Regards

Geoff
Last edited by Fossil on Sat Mar 21, 2020 4:23 pm, edited 1 time in total.

classiclife
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Re: Electric water pumps

Post by classiclife »

Hello Geoff,

This is an interesting thread and thanks for posting.

From your last post, may I presume the following:

1- electric fans are front mounted ??

2- there is no shroud between the rad and mechanical fan ??

3- the rad was in situ prior to your ownership ??

1- I am not a fan of front mounted electric fans as they cause there own obstruction with directional air flow when moving. I appreciate that in some cases this placement is the only option, as I had to when I owned a Sunbeam Alpine.

2- the distance of the rad from the mechanical fan is more of a concern - the larger the distance the less effect of any air being drawn in. What you end up with is hot air being circulated around the front of the engine with little through the rad fins, hence a reduction in potential cooling efficiency. To get around this you could incorporate a shroud to act as a wind tunnel which will by its very presence draw air directly through the rad. The V8 saloons are a good example of such. The depth of the shroud is immaterial as long as the passage is complete from rad edge and goes past the mechanical fan blades, in essence just an overlap.

3- what do you know about the rad other than slightly wider with 3x rows. The rad core may well be clogged and this could be a step in the right direction to have the cooling issue sorted. I would suggest this route first as all the above can only aid the rad not replace its job. These days modern high-efficiency performance cores are fitted - if requested - usually with an extra row. The cooling performance increase is significant.

The days of flushing a rad through to achieve optimum performance have long been dropped, once a rad core starts to clog it really is the end of the road. You can keep the inevitable at bay by using a 50/50 AF mix with DISTILLED WATER but the use of tapwater is a quick road to clogging.

You mention engine bay heat soak, that is a common issue with many classics - my Triumph Vitesse suffers from it. However, with the electric fan remaining on after the ignition switches off goes some way to address the issue and helps to cool the coolant and move the air around the engine bay.

You joke about louvres, but if you think about they were there for a reason and it was not for cosmetic appreciation - a tad drastic for your situation !!

IMHO, which will probably be shot to pieces, the above are decent steps to ensuring the goal you wish to achieve. I know from your info that the set-up on the car is a bit different but the basic principles of cooling are the same.

Regards.

Richard.
Last edited by classiclife on Thu Mar 26, 2020 1:49 pm, edited 1 time in total.
1968 Daimler V8-250 Saloon
DLOC East Sussex Area Representative.

Southern Classics Society Events Co-ordinator.
www.southernclassics.org.uk

Fossil
Posts: 442
Joined: Sat Feb 13, 2016 5:08 pm
Location: Helensburgh, Argyll

Re: Electric water pumps

Post by Fossil »

Hi Richard

Thank you for your further very perceptive thoughts, I waited a few days to see if there would be any other comments.

You are quite right, the fans are front mounted, I share your concern about occlusion of the rad core, but I switch them on whenever there is any doubt about air flow.

No, there is no shroud between the rad and the mechanical fan, but it is as a source of cooler air flow through the engine bay at slower road speeds that I consider it would be most useful. Any shroud would need to be of considerable size to function efficiently, so I'll rely on the elec fans to provide rad air flow at slower speeds.

The radiator was in situ when I acquired the car and has appeared to be reasonably adequate, although the proof will be in its performance once back on the road. I agree with your thoughts and suggestions regarding blockage and the consequences thereof; if required once mobile again I'll certainly consider having it re-cored if its performance is genuinely suspect.

So to conclude, I'll not be considsering an EWP at all until I've had the opportunity to assess the function of the entire set-up with the standard mechanical WP once it is at the stage of being re-introduced to the road. Then I'll look at the adequacy of the radiator's function, the adequacy of the standard WP (with the aid of a digital thermometer as suggested by Ian) and possible further options for dealing with underbonnet heat. If I do at any time decide to fit an EWP I'll remove the std WP impeller.

Thanks to all for your thoughts and suggestions.

Now back to my chosen place of self-isolation, the garage; but first I have a little household shopping to do, complete with blue nitrile gloves.

I wish all Forum-users well, esp those of my generation, the over-70s. Be careful and keep a safe distance!

Regards

Geoff

classiclife
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Re: Electric water pumps

Post by classiclife »

Hello Geoff,

Thanks for the update and I will be interested to hear how you get on with the situation.

On my V8 saloon I have removed the mechanical viscous unit and replaced the cooling aspect with a 14" 160W electric fan. This is mounted between the rad and engine thus keeping the front of the rad obstruction free.

On the saloon the shape of the grill does not help matters - different for you I appreciate.

Whilst running-in my newly rebuilt engine with 800 miles now clocked up I have not witnessed nor had any issues with cooling efficiency as demanded by the engine or car generally. In fact the fan has yet to cut-in (yes it des work !!) and that includes elements of slow moving traffic for periods of time.

I just wonder if the above stance may be appropriate for your car. One thing I will say is that running a 80W electric fan is pointless and will do little to help the cooling process - you really do need a powerful puller - hence I have gone for 160W but the absolute bare minimum should be 120W.

It is possible to fit a 220W fan and I did consider this but 160W seems to work well. Additionally I was concerned that the 220W fan may inadvertently suck in small dogs and young children which is bound to clog the rad core :D !!!!!!!

Regards.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Area Representative.

Southern Classics Society Events Co-ordinator.
www.southernclassics.org.uk

Sonus
Posts: 196
Joined: Wed Apr 13, 2016 2:19 pm

Re: Electric water pumps

Post by Sonus »

I will fit an Davies Craig EWP115 to my tunes Daimler 250 Saloon V8. I am planing on using the water pump housing as an inlet by removing the pulley and then removing the pulley shaft and bearings. I will then machine the shaft housing so that this will become the inlet. I will use the Davies Craig water pump and cooling fan ECU to control the lot. I am also considering fitting temp sensors to the blanking plates on the end of each cylinder head to better keep track of engine temps.

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