electric water pump

[Plechtan]

We decided to put a little Hard Block on the bottom of the water jacket of the LSR motor, it will stiffen up the bottom end and maybe help with harmonics. The problem is that the water pump opening is maybe 1/4" up from the bottom of the water jacket, so with the hard block, I cannot use the stock pump.

I have found several remote mount electric pumps that are designed for street use, the range from 35-55gpm. Drag race electric pumps are about 20-15 gpm. So now i have a pump, but i needed something to seal the opening in the front of the block. I thought about taking a 1/4" piece of aluminum , welding a bung on it and just bolt it over the hole. Screw a street elbow into it and be done. But looking at the block, the water would be blasting directly on the front of the cylinder wall of #1 cylinder. The stock pump throws the water to the left and right side of the water jacket. the impeller almost touches the front of the cylinder, so there is not much water flow there at all.

So plan B, I took the stock water pump and got the shaft out of it( not easy), then i put it on a band saw and cut off the tower that supported the shaft, then took a die grinder and removed the inner part of the shaft support. I now have a very large hole in the front of the pump. I will cut out a piece of aluminum and have it tig welded over the hole. I still have the same basic problem, the water will blast on #1 cylinder. I thought about it a while, then came up with the idea of using a piece of 1" aluminum angle set vertically in the pump opening. the angle would be positioned so that the V would be in the bowl of the pump housing I think this will work well to deflect the coolant left and right, if not i could weld a deflector plate on the front of the angle.

So now as I am looking at the pump housing I notice a hole on the upper left side of the pump, near where the heater hose line exits. What does this do? Why would you have a hole from the water jacket back to the suction side of the pump? I went out and checked a block i had, and it seems that this is a bypass connected from the head, prior to the thermostat. This would insure a water flow through the block with the thermostat closed. well since i have removed the guts of the pump, this is no longer the suction side of the pump. So either i have to isolate the port and run a line to the suction side of the pump, or just plug it and either not run without a thermostat or have a hole in the thermostat to make sure i have some water flow when the thermostat is closed.

Now for the pump, one thing i like about Electric motors is that you can control the speed of them. The standard electric water pump runs at full speed all the time, but do you really need 55gpm if the thermostat is closed? I found a reaonablally inexpensive motor drive i could control the speed of the pump with. You set the speed with either a 0-5V command, a potientometer or some resistors. My thought was to run it a a slow speed while the engine warms up, then use a thermostatic electric fan switch to kick it up to a higher speed when the engine warms up. I may be able to control it form the ECU, I am checking. I would probably keep a pot in the drivers area to adjust the speed,

[5-90]

Hm - I've been kicking around a similar idea for some time (no particular reason - just because I've done it on other engines, and I've not seen it on an AMC six...)

I'm sure you're going to be using an impeller pump, and not a positive displacement pump, right? If you use a PD pump, you're going to need to pull the thermostat and allow full flow, or you'll blow something out. An impeller pump (like the OEM,) will allow a certain amount of "bypass" so you don't blow a seal.

What size was the hole left in the pump housing tower? It won't accept a pipe plug? Just wondering (got pix?)

The side port in the pump is to feed coolant to the heater core circuit - follow the lines, and you'll note it runs back to the HC then up to the thermostat housing. This is what gives you cabin heat, and it also provdes a flow bypass for when the thermostat is closed (above and beyond the bypass provided by the impeller pump - I'd consider both of those necessary. This helps to keep system pressure controlled by heat, rather than by pump action.)

The approach I was thinking of, however, was to remove the pully and possibly the shaft flange, and figure a way to couple an electric motor directly to the pump. Include a rheostat or a PWM controller to control pump speed, and possibly use a thermistor for an input signal to give temperature-sensitive pump speed control (very slow while warming up, and variable high speed to maintain temperature. Probably just remove the thermostat entirely, but my 88 overheats every damned time I put one in anyhow - even when I did a full flush and a /whole/ /new/ cooling system. One of three vehicles I've had like that...)

I'd like to see your approach (if you don't mind) and see information on your revised belt routing.

[Plechtan]

The pumps are impeller type, so you can run them dead headed. The hole is about 5/8" I have a block with the head off and the hole is next to the head bolt on the passenger side in the front. I have an aluminum head, so i could put a plug in from the bottom. you may be able to adapt one of the belt drive kits for a chevy water pump to the jeep, but most of the ones i have seen are not recommended for street use. Putting a motor on the front of the pump is impractical because of the tight clearance to the radiator.

I will just have a crank pulley and an alternator, so my setup is pretty simple, i will probably use an alternator bracket from a CJ with a serpentine alternator. The LSR truck is strictly for race use so i don't need the other accessories. For street use i would recommend taking the impeller off the pump and leaving the shaft and bearings in place. you would then not have to change the belt setup.

The temperature controlled pump is a great idea, but i have not found a controller for a reasonable price. The Haltech ECu will output a PWM signal for an electric fan control, so i guess i could use this to control the pump. The controller also has a couple of spare outputs that you can program to turn on at a specific temperature. I was thing on having a slow pump rate default, then when i hit 180 or so go to a higher speed, then if it hits 200 go to top speed.

[Plechtan]

Here is a picture od the pump with the tower cut off.

IMG_7118-1.jpg

[Plechtan]

Here is a picrure with the inner bearing support removed.

IMG_7120-1.jpg

Here is a rear view with the chamber opened up. Notice the hole at the top for the bypass from the head.

IMG_7121-1.jpg

Here is the angle inseted as a deflector,

IMG_7122-1.jpg

This is a wj 2001 water pump and probably looks different from yours.

[TurboTom]

While I am a pretty big fan of engine driven water pumps (Block pressure is a good thing) especially on an engine that will be at WOT for more than 1/4 mile. I would suggest you just make a plate with 2 fittings, Y them on the outside and bolt it up.
If your set on running an electric pump. Just put it on a temperature switch.

[gradon]

I understand the desire to get rid of the belt driven accessories and shortening the belt. You'll find a solution by the looks of it--a variable speed/temp controller would be nice.

[Plechtan]

While I am a pretty big fan of engine driven water pumps (Block pressure is a good thing) especially on an engine that will be at WOT for more than 1/4 mile. I would suggest you just make a plate with 2 fittings, Y them on the outside and bolt it up.
If your set on running an electric pump. Just put it on a temperature switch.

I thought about the plate, but the pump flows 55gpm or about 1 gallon per second. I would need some pretty big fittings for that, maybe 2 AN20 Size. So I would probably have to have a machine shop make a plate with 2, 1 1/4" pipe tapped holes in it. The water pump modification is somthing i can do in my garage. The modified pump will also sit close to the block allowing me room for electric fans. Things are tight between the engine amd radiator on the Xjs and Mjs.

[1bolt]

Interesting so how much pressure can a mechanical water pump maintain inside the engine? At what point does the pressure just push past the t-stat? Obviously it's already got the bypass hole, so it's already not compressing water into a sealed cavity.

I'm guessing by the Autometer Water pressure gauges I've seen that it can be quite high (they go to 30-35 some even 60 PSI)..

I wonder how much difference in PSI would be between mechanical and electric.

I know the common perception is an electric water pump only frees up a couple hp on a dyno, but I'm not sure how that's possible if the water pump is compressing water to similar PSI as say a supercharger which takes a lot of hp to work... Granted a SC is compressing easily compressed air (and doing more work for the same PSI), compared to water which doesn't compress easy.

[Alex22]

Just thinking out loud here, maybe over complicating things, but...
Have you thought about putting one suction fitting in the front of the water pump block off plate and one on the back side of the engine to try to increase water circulation.
We have been working on a few SB2's and SB2.2's [Chevy nascar type] at work and they use a small fitting to draw water from the heads between the two center exhausts which increases water circulation in the engines.

How high do you plan on going with the hardblock?

[TurboTom]

Interesting so how much pressure can a mechanical water pump maintain inside the engine? At what point does the pressure just push past the t-stat? Obviously it's already got the bypass hole, so it's already not compressing water into a sealed cavity.

I'm guessing by the Autometer Water pressure gauges I've seen that it can be quite high (they go to 30-35 some even 60 PSI)..

I wonder how much difference in PSI would be between mechanical and electric.

I know the common perception is an electric water pump only frees up a couple hp on a dyno, but I'm not sure how that's possible if the water pump is compressing water to similar PSI as say a supercharger which takes a lot of hp to work... Granted a SC is compressing easily compressed air (and doing more work for the same PSI), compared to water which doesn't compress easy.

The difference is the volume of medium that each is moving. The SC is moving ALOT more volume at the same pressure. The water pump is also not a positive displacement pump like the SC.
Be carefull as an electric pump COULD take more HP from the engine if you use an alternator for charging. Anytime you change power sources ( Mechanical - Electrical /Electrical- Mechanical ) There will be losses.

[Plechtan]

Water pumps used on cars are usually centrifugal in design. This is true for electrical or mechanical. Since the pump relies on centrifugal force to move the water, the higher the rpm, the more centrifugal force available, so more water can be moved. if the volume goes up and a restriction exists, then the pressure will also go up. more pressure, more volume, more energy is used. If the energy is not used to move the water, then it just translates into additional heat in the coolant. The assumptipon that the electric pump is doing the same thing as the mechanical is wrong. If you search the internet, you can find tests where they have changed from an mechanical to an electrical pump and gained anywhere form 4 to 13 hp. The electric pump does not consume more energy as engine RPM increases.

The pumped used with the stamped sheet metal vales, or the cast vanes are generally a very poor pump. they will not work well at high speed. But then again they do not have to, if they move enough water al low speed, then at high speed they can loose some efficiency. The later model jeep pumps are a little different, the impeller is made of plastic and is very efficient. It will continue to move more water and create more pressure as speed increases. I plan to tap a 1/4" pipe hole on the drivers side of the block about 2" back from the water pump. Ill put a pressure gauge in to see what's going on. It would be interesting to try this on an engine with a stock water pump.

[Plechtan]

Just thinking out loud here, maybe over complicating things, but...
Have you thought about putting one suction fitting in the front of the water pump block off plate and one on the back side of the engine to try to increase water circulation.
We have been working on a few SB2's and SB2.2's [Chevy nascar type] at work and they use a small fitting to draw water from the heads between the two center exhausts which increases water circulation in the engines.

How high do you plan on going with the hardblock?

The water in the jeep goes through the block then enters the head at the rear and goes to the front of the head and out the thermostat housing. I don't think a fitting in the rear of the block would help. The drag race guy pumped the water in through the freeze plugs so he would get good cooling between the cylinders.

But maybe it might make sense if you put a return line at the back of the block and a separate pressure feed to the rear of the head.

We used 3/4- 7/8 of hard block

[5-90]

The heater/bypass port is threaded 3/8"NPT - so just a plug can be put in there (that's pretty standard for most water pumps in general on American vehicles - that's why I've never gone and bought one of those damned cheap stamped hose nipples for a water pump. Get brass pipe instead, make an ell out of it - and that keeps the rubber hose away from the belt and backside of the pully as well.)

Note that the pump is an automotive cooling system is merely a circulator, it does not RPT /not/ generate any pressure! Pressure in the system is a result of temperature - and it is this pressure that works to move the boiling point of the coolant upwards (1psig of pressure = 3*F rise in boiling point of water and aqueous solutions. 212* at STP becomes 242* at 10psig, for instance.) The pump, being an impeller type and not a positive displacement type, doesn't generate pressure (by the same token, a centrifugal supercharger doesn't directly generate any manifold pressure - it works because of inertia [speeding up the airflow in the manifold] and due to the compressibility of gasses. Liquids don't compress.

(For an example of a positive displacement pump for liquids, tear apart an oil pump for a gerotor type, or a fuel pump for a variable-volume chamber vane type.)

I maay have to dig around to see if I have a pump or three floating around - but it seems to me that a pancake motor could be found to drive the impeller found in the pump to begin with, perhaps - working out the clearance issues? The shaft could be sealed in the plate that would be welded in place of the tower - when cut off - and perhaps shortened and keyed to the pancake drive.

Hmm... Don't get me started on this, or I'll put a note on my corkboard and start looking for parts...

[yuppiexj]

I maay have to dig around to see if I have a pump or three floating around -

That's funny. I just did a water pump yesterday and tossed the old one into the pile, there were already 4 of the darn things there already.

/end thread hijack