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MG MGB GT V8 Factory Originals Technical - Electric water pump conversion

I have had inquries about a pump kit for V8 applications. I would consider this if there was enough interest. SEE BELOW:

Killer Bee Conversions has produced a remote electric water pump conversion kit for all A or B series engines and are for sale as of this writing. See Keith Calver tech article at Below is an excerpt from that article.Email inquiries to

Recent testing has seen the growing popularity of electric water pumps. These have to be the ultimate answer, as their pumping capacity remains constant, as they're completely independent of engine speed. Consequently cooling efficiency is far greater. The only two drawbacks being their initial cost, and installation, as adaptors have to be made up to blank-off the water pump mounting hole. Both, however, are well worth it - the results are outstanding. Not to mention the fact the water pump consumes power to drive it and reduces accelerative power output - to the tune of 4 bhp on a small-bore engine and 2 bhp on the large-bore ones! A further benefit is that the pump can be left running with the engine off after a race/hot/long journey to reduce the problems associated with the 'heat-sink' effects of non-circulating coolant at stand-still. For further information on electric pumps, see relevant article.

Dann Wade

Wait, this is silly:

>Not to mention the fact the water pump consumes power >to drive it and reduces accelerative power output - >to the tune of 4 bhp on a small-bore engine and 2 bhp >on the large-bore ones!

First of all, it is not going to take any more power to drive the water pump on a small bore engine than a big bore.

Second of all: do you think the power is free? The increased drag from the alternator not only counters any advantage here, but since the alt is not 100% efficient, in fact you may well end up losing power.

Please: w&*k off. Advertising on this BBS is bad enough, but false advertising is worse still.


I donít feel the same as Ted. Such a device could help, but not on the points debated. The important goal would be a more compact system that shortens the overall length of the motor at the front to allow more radiator clearance without adversely affecting the cooling.
George Champion


Search for Meziere electric water pumps. The pump fits in place of the mechanical one, needs no pulley and is shorter as you suggest. The only problem is that the 35 gals water flow is equal to aprox 2,500 rpm flow and after that the mechanical pump is faster. They do a heaby duty one which has a faster flow which would be more equal to a higher rev. I am still making up my mind about it.
It looks like a very nice piece of kit. I'd like very much to hear from someone who has used one.
Marc Gander

Ted,I am a loyal member of good standing and have made some worthy contributions to these columns.Your comments are duly noted but unless you are an engineer and have the credibility to back up such ridiculously inaccurate statements then I suggest you find another audience. I hope you don't have the gall to persist in making a fool of yourself. This conversion is a suggestion to help overcome the overheating problems the V8 owners seem to always encounter.( see archives) If you don't have these problems ... fine, just give the other members the chance to recognise a possible cure for their problems. It's people like you who would pull the wings off a fly, then say it can't fly. Dann Wade

George, Thanks for your support.This is a compact system. It makes lots of room up front and the pump is mounted remotely and requires no belts.
Dann Wade


How about some specs and some pictures. I couldn't find much in the article you referred to.
Marc Gander

Ted; You have a valid point about the power draw being different on big-bore versus small-bore engines, and I queried Mr Calver about that and a few other curious inaccuracies when he first wrote that article. He conveniently forgot to answer that part of the question :-)
He did, however, explain why an electric pump uses overall less power than a mechanical one. It seems that (on an A-series) at around 2500rpm a mechanical pump is moving enough water to cool an engine putting out over 150bhp. Turning the pump faster is unneccesary, and at extremely high rpm the pump can cavitate, reducing efficiency.
Conversely, at idle speed a mechanical pump may not be moving enough water to keep a highly tuned engine cool.
An electric pump bypasses the pump-speed problem. It runs at one speed all the time, eliminating cavitation and wasted power, moving the optimum amount of water all the time.
Rather than getting something for nothing, an electric pump eliminates the unnecessary drag associated with a mechanical pump, and thus liberates a few hp at high revs.

(Member of good standing etc.)

PS 'Big-bore' and 'Small-bore', as used by Mr Calver, are the accepted terms used to distinguish the two bore sizes available in Mini engines (which is what Keith was describing in the article)


Growler has a point, my car runs quite cool at 2500rpm but the radator has difficulty in coping with heat when stationary. It's all to do with airflow I know, but extra water flow at low speed must surely be beneficial. Re power loss, surely it's not too relevant with V8's.

Michael barnfather

The potentially more useful side of the electric waterpump is to have a timer on the supply to keep the pump running when the engine is stopped. Used in combination with electric cooling fans it should reduce problems with heat soak when you stop.

Off topic really I know but has anyone seen any information on power comsumption of alternators - does the power consumption increase with electrical output? Current motorsport thinking seems to be to reduce the inertial mass, which I think is also the major gain of the electric waterpump.

Dave Brooke


If you are going to advertise, I agree with Mark's comments specs and pics would help.


The loss of flow over 2500rpm may not be a problem as Growler has indicated esp with Ali rad.


Thanks for your comments. I will take everthing into consideration. My opening statement in my first message was to open the door for all those interested enough to give me the incentive to machine up a prototype assembly. This takes many hours of development and of course lots of money let alone finding a V8 MGB owner who was willing to go the switch. It would be a labor free conversion for any volunteer. Lets wait and see if there are enough interested people to warrant futher research. If it happens then I will indeed submit all info and photos on my website. Thank you. Dann Wade (
Dann Wade

Electric water pumps have been available for years. Summit Racing has them listed for small and big block chevies, fords and chryslers. They are optionally able to be controlled to turn on/off at preset temps. Flow rate as a funtion of pump motor speed would, I believe, be adjustable as any DC motor, up to some max, possibly governed by cavitation or max motor design speed. Practically speaking, you'd probably run it wide open and govern its on/off with a thermostat. Amp draw on one example is 5.8 amps.

As amp load on an alternator increases, so too does its resistance to turn due to an increase in the magnetic field strength through which the rotor is drawn or spun. The sympathetic operator senses this because of the way the engine speed is affected when additional electrical appliances are turned on/off.
Art Dodge

My understanding is that simply moving water through the rad faster is not necessarily helpful. Of course, if you move the water too fast through the rad, it doesn't have a chance to fully cool down in the rad, and if you don't move it fast enough, it gets too hot for the rad to fully cool it down. This is why car designers spend a good deal of time coming up with complementary components. It's also why in MGs, in road applications it isn't always a good idea to remove the thermostat (even if you use the blanking sleeve).

Of course, the major, major, MAJOR downside to electric water pumps is that if they stop running when you're out on the road, you are not getting home, period. An electric fan crapping out isn't the end of the world, but a water pump definitely is. That's why for years they were recommended only for racing applications ... and in fact they aren't widely used in circle-track, just drag-racing. As you know, drag racers typically kill the alternator seconds before launch and make their pass with the electrics running off the battery, so that there's no alternator load.

I realize this fellow claims to be an engineer, but the horsepower large/small engine claim is, IMHO, purely nuts, as is the apparent supposition that an electric water pump doesn't load up the alternator and so increase the load on the motor. (True, though, that above 2500 rpm there may be an incremental savings in power. I guess it depends how efficient the alternator is.)

It would certainly be good for cool-down, though. However, once you kill the ignition, the alu Rover cools down pretty darn quickly, esp. if you have an electric fan to get the air out of the engine bay.
Bill Withum

A unit has already been engineered. USA distributor made in OZ. Have any of you OZ'ers seen it? Clever use of electrics to control pump vs. using thermostat.
Tom Lang

Dave Brooke wrote:

...information on power consumption of alternators - does the power consumption increase with electrical output?


Yes, the power load on the engine does increase with the electrical load on the alternator. How much power drain?

A 60 amp alternator, at 14.6 volts, provides 876 watts maximum of electrical power. 745 watts of electrical power is approximately equivalent to one horsepower. Thus, assuming for the sake of argument that the alternator is only 50% efficient, The max horsepower drain from electrical loads would be a little over two horsepower.

One of the benefits of an electic water pump, as has been pointed out, is that it draws the same amount of power regardless of what the engine is doing. A mechanical pump, on the other hand, has an increasing power draw with rpm. At high rpm, the power drain can be significant.

From a "freeing up horsepower" standpoint, swapping to an electric pump is probably not worth the trouble ($$$$) for a street driven car. However, if you are having cooling problems, or if you drive your car competively, it may be of benefit.

Bottom line is - do your research, understand the trade offs, and know what you are getting before you take the plunge. Sometimes it's hard to filter through the chaff to get to the wheat in BBS discussions of subjects like this.

Dan Masters

> At high rpm, the power drain can be significant.

Dan, is this true? I'd always thought that water pumps cavitated at high rpm and because of that the load didn't go up in proportion to rpms ... rather it tapered off. I'm pretty sure someone who raced stock cars once mentioned same. Anyhow somebody must've figured this out before!
Bill Withum

I would expect the power consumption to increase exponentially with the increase of RPM. Just as fuel consumption increases exponentially with an increase of speed due to wind resistance, wouldnít the fluid resistance through the water passages and radiator do the same?

Marc, the electric water pump you pointed out at is the first I have seen for these motors, but like all the others with the electric motor mounted on the pump in the standard location, it is deeper than stock rendering it useless for MGB V8s. Still itís nice to see someone catering to this engine.

Tom, I had seen the one you pointed out at before and it looks like it may work after an adaptor were made for the original water pump location. Still it looks rather big so squeezing in someplace would be a challenge. My eyes are still sore after they hit the monitor when they bugged out upon seeing the price!

Dann, is your plan to package this pump with an adaptor for the Buick/Rover? Have you already done one for the V6 and do you have pictures of it? Too bad Ohio is so far from Arizona :-(
George Champion


I had understood that the reason why a thermostat removal is replaced with a restrictor plate is apparently because the rearmost cylinders are not as efficiently provided with coolant and the pressure is needed to force the water to that area. I understand that there is some mod available so that the rearmost cylinders are brought into the natural direction of waterflow. Apparently it is for this reason that the rearmost cylinders are always slightly hotter than the forward ones.
This sound quite amazing to me but I read it all somewhere and it seemed to be a pretty authorative article. The mod involves drilling out a channel somewhere and then re routing the coolant hoses differently.
I'm certain someone will respond to this comment and confirm or decry.
Marc Gander


A factory design should not allow the pump to cavitate at any rpm below red-line. On a modified engine/car, this may be the case if the cooling system hasn't been carefully thought out. If the pump does cavitate, this would be another reason to go to an electric pump on a race car. Cavitation will quickly destroy a water pump (I'm not a mechanical engineer, but I worked for many years as an electrical engineer in a nuclear power plant design dept, and this is what the mechanical engineers told me. Cavitation was to be avoided at all costs, and I designed instrumentation systems to warn of cavitation so the offending pumps could be shut down).
Dan Masters

What I want to see is a proper set of dyno results for alternator power consumption against electrical output at various rpms, plus effect on apparent inertial loading caused by the various options for turning off the alternator ( output disconnect, field excitation disruption etc ).

The comment about the waterpump power losses for large and small bore engines is valid in its original A series context, it has been repeatably measured by reputable engine tuners.

I'm sure someone will say otherwise but it seems to me that general problem with V8 mgb's is getting the heat out of the cooling system. I've monitored the radiator inlet and outlet temperatures and the air temperature before and after the radiator under road and race conditions on a car with a standard engine - getting enough air through the radiator is the real problem in the car concerned.

Dave Brooke

Davies - Craig have been going for years here but I was unaware they had an overseas market as well.

They originally started making replacement / aftermarket and OEM thermatic fans for a range of cars and still do. The product is similar to items made by Kenlow and others and is very popular here for people towing caravans, boats etc especially in the high temps in Australia.
Their products have a good reputation for reliability, value for money and ease of installation.

The electric water pumps are used here by a lot of racing teams and also have a sizeable following by the serious aftermarket go faster brigade (weekend track racers, hillclimbers and so on).

As an aside I am not in any way connected with them,(not even as a customer)and "have no interest" as the expression goes.

HTH, Cheers, Pete
Peter Thomas

To whom it may concern.I have answered these questions the best that I have had time to do so. I don't want to hear a lot of guff about all my inaccuracies from other members. These answers or theories are as much as I can recall at the moment. My opinions or theories are meant to incite thought not critisism. Take it for what it's worth. Thank you.

As far as the worthiness of an electric pump vs. a mechanical pump.

First of all the older V8 and V6 and 4 cylinder variety engines used in MGBs usually have V-belt drives. Realize then that there is significant friction in these systems because of the contact of the v-belt with the sheeves or pulley grove.The larger the pulley the more contact surface, thus more friction. Thus the advent of seperpentine belts to reduce this friction. Also realize that the pressure inflected to the bearings on a mechanical water pump should be considered. The electric pump addresses these problems. The energy/power consumed by an electric pump is not generally recognized to be as significant as power robbing, friction losses in a mechanical pump.

>At high rpm, the power drain can be significant.

Dan, is this true? I'd always thought that water pumps cavitated at high rpm and because of that the load didn't go up in proportion to rpms ... rather it tapered off. I'm pretty sure someone who raced stock cars once mentioned same. Anyhow somebody must've figured this out before!

Bill...This is my opinion and experience. Water pumps will cavitate in automobile and other engines that have quick revving capabilities or not connected to a load when the they are suddenly accelerated. To explain this action in ordinary terms would be to consider the volume and weight of the water being pulled or pushed through a narrow tube. At normal rpm ( road speeds) when the water is moving at a steady flow the mass of the weight is moving as one unit.

When a sudden throttle flick or sudden power surge is supplied from the engine, the vanes of the pump " slip in the stream" and the pump spins freely causing a " hole" to be formed in the coolant from the direction of coolant flow because of inefficences of pump design, physical properties of the liquid being transported, restrictions in the coolant circuit or in general, physical laws that govern the action of a common vane type pump. There is a point to which liquids cannot be properly moved in a tube at higher RPM. Water tends to become "stiffer" and make account for the power losses at higer RPM. Any one can tell you that ever did a belly smaker in a swimming pool or fell into water from an elevation, that it's fairly stiff at higher speeds:) Not a good example but humorous. It is generally accepted that quick revving causes cavitation. A good example of cavitation is noticeable with a common out board engine when turned on to full throttle from an idle. You can't move the lake but you can overcome the speed at which the water can move back into displaced water.

Dann, is your plan to package this pump with an adaptor for the Buick/Rover? Have you already done one for the V6 and do you have pictures of it? Too bad Ohio is so far from Arizona :-(

George..I want to do this to help the V8 cars at the moment. Making a buck for all the research would help too. I would think the Buick V6 with have a similiar pump configuration so it would be feasible to carry it over to those models. I've market a kit for the 60 degree GM and Mini A and MGB B series engines. I have a friend in Scottsdale who is very familiar with MGBs and my products. He would welcome a visit from you should you want to chew the fat. If you haven't visited our website please do so. All my conversions will eventually be described there

Thank you all for your comments. Dann Wade
Dann Wade

Dave Brooke, I agree the biggest factor in cooling these motors is airflow. My cars runs fin at highway speeds with 55 mph air forced through radiator and the car moving away fro the expelled heat. At idle the fan just doesnít move enough air and what it does move through the radiator it canít blow out the bottom of the engine bay. I have wanted to monitor the radiator inlet and outlet as you have, but couldnít figure out how. I hadnít even thought of monitoring the air temperature in front and behind the radiator, but I did try to monitor the air speed output of the radiator fan without success. Would you post your findings of before and after temperatures and your methods of monitoring please?
George Champion


Sorry but i need to correct you. With a pulley/belt system, the friction is not between the belt and the pulley. this simply because there is no movement between these parts. The only power loss is the force it takes to "bend" the belt when it meets the pulley and "straigthen" it when it leaves the pulley.
This costs energy and this is the los in a pulley/belt system. The energy is transfered into warming up the belt and pulleys.
futheron i am sure that the general effiency of an electric waterpump with an alternator is worse then a mechanical waterpump. The advantage of the electric waterpump is what is described earlier is that a mechanical waterpump get a too high rpm once the engine revs. This high rpm is not needed and causes a lot energy consumption. The advantage of the electric pump is not related to the friction but to the rpm.

Peter...... just couldn't resist? You are exactly wrong. The belt is driven into the the V of the pulley by tension as it makes contact in the groove and is forced into the sheeves(known as friction). The same action occurs at the belt leaves. There is a minimum of 3 pulleys on most water cooled vehicles. There is insignificant heat built up from flexing. On modern vehicles with several acessories that use 6 or more pulleys the friction is minimal when a serpentine system is used. They reduce power consumption and add to fuel economy. The serpentine belt has several very small V grooves in the belt and it is relatively flat in comparison to a standard V belt. This design reduces friction and provides better "tooth" because of the increased surface area of the multiple small V's. Thanks for paying attention anyway.
Dann Wade

One factor of an electric water pump is COST. I have a Foird 302 which has mass produced units available "off the shelf", they all run in the $250+ range. Not a cheap item. I still consider it in the back of my mind, but it would mean re-doing my Alt mouning as it sould not have the water pump to pull against like normal.. but the idea of shutting my car off and having the pump and fans run to cooler her down is very interesting.. Especially for those play days at the local track..

Larry Embrey

I've looked a the electric pumps for exactly the reason Larry suggests - stop the engine but keep the cooling system running if its all rather hot.

This shouldn't need such a large pump as a running engine and could also act as a booster when idling in traffic if the engine driven pump performs poorly at idle.

Problem is where do you add it without impairing the system?

Dave Brooke

Have you considered the secondary electric coolant pumps used by Audi in the 5000 Turbos. They are used to cool the turbo after a hot shutdown. A temp sensor turns it on and the fan for a few minutes. A takeoff for the pump came from the head and returned into the heater. Pump is plastic and I think its around $100. I am not sure but I think other turbo cars now run simmilar systems. This type of setup would help dissapate heat from the heads after hard run.

Larry, The Meziere pump is 192.50 and is a strikingly nice billet pump.

One advantage to using an electic pump would be that you could more easily reroute the plumbing to have the heads cooled first instead of the block, as is done on many high performance engines.
George B.


Where are you seeing this pump for 192?? All the ones I see ready to install on a SBF are $250.

I paid $140 for my high flow Milodon crank driven unit, nother $50 could have gotten me all set.. Elect would be very handy on those days I hit the drag stip so I could cool the car down in the staging lines...
Larry Embrey


I found the ideal way to monitor radiator temperature.

My brother bought me a digital wine temperature thermometer for Christmas.
Now we never have the wine in the bottle long enough to use it, but I was having trouble with my V8 cooling, and found that it is ideal for checking.

It has a long probe on the end which just fits between the radiator vanes, and it reads up to 100c in 1/10 degrees, it soon showed me the effect of the adjustable thermostat on the cooling fan cutting in.

Mike Barnfather
Michael barnfather

I have been told another thing that can greatly affect running temp is the thermostat in the system. Now for EFI cars you don't have the ability to drastically alter the coolant temp due to computer adjusting things based on temps, but for carbed cars you can sometimes get away with a significantly lower rater Therm. I am borderline with my stock MGB radiator, yes I plan to get it done long term, but and far in debt already and can't spare the extra 200+ to get recored.. A guy in SBF forum recommended I try a 160* therm. as it would start cooling the block before she got real hot and that keeping cool from 160 would be easier for the rad than bringing the temp down from a higher temp.. I might give it a try..
Larry Embrey


Thanks for the answer. I pictured a probe inserted into a radiator hose as on some aftermarket fan thermostat switches.

My unsuccessful attempt at measuring airflow involved metering the voltage generated by a small fan placed in the air stream of a radiator fan.

George Champion

Larry, the pump I am referring to is part # WP136S made by Meziere.1 800 208 1755 They have a website but I didn't see the pump there. They are very knowledgeable and helpful. Dann

This thread was discussed between 14/05/2002 and 21/05/2002

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