The best location for an electric water pump SBC V8 conversion, The best location for an electric water pump SBC V8 conversion Options

[BRAVE_HELIOS]

Hey all,

Inching closer to going electric on my V8 conversion car. Right now; going through the process of cleaning out radiator and water passages/block with ThermoCure, then Prestone citric acid flush. Assuming I get a really clean system but not fix the run hot situation; I will go electric. Where is the best place to mount the electric pump? It would seem that the easiest way to go in my case is with this:

http://www.jegs.com/i/JEGS-Performance-Pro.../50930/10002/-1



It a 50 GPM unit that should bolt right up to the Renegade remote water pump housing already in place in my car on the lower left hand side of the engine... that is assuming there is enough clearance between the water pump and the firewall.

Would this work? I have heard stories going back and forth about mounting the pump by the radiator or by the engine.

[BRAVE_HELIOS]

Some pictures of my current setup...

[914GT]

Best location is the lowest point in the cooling system and at the rear (below engine). During acceleration the suction side of the pump will have highest pressure and helps the pump when you need maximum flow.

[BRAVE_HELIOS]

Best location is the lowest point in the cooling system and at the rear (below engine). During acceleration the suction side of the pump will have highest pressure and helps the pump when you need maximum flow.

So then my idea of using the Jegs pump and mounting it the Renegade remote water pump housing is a good idea (as long as clearance allows)?

[BRAVE_HELIOS]

As a side note... I just took the car for a short drive; still with the Prestone Radiatior Flush and Cleaner running through the cooling system. I'm doing the heavy duty cycle cleaning... 3-6 hours of 'normal' driving. Of course, always with an eye on the temp gauge. Anyway; today after getting back from my short drive, I noticed that the overflow bottle in the trunk was actually bulging quite a bit. There is no pressure cap on it, just a simple snap type cap, yet it was definitely looking like it was under pressure. Temp gauge read around 180 and the electric fan was running.

Is this normal? Sometimes I wonder if I have the expansion tank plumbed correctly. Can you tell by looking at the pictures and descriptions that it is installed correctly?

[BRAVE_HELIOS]

These custom fabricated cars... you sometimes just don't know how to apply standard processes.

Case in point; Along with the Prestone Radiator Flush and Cleaner liquid, I purchased their Flush and Fill Kit, complete with T's, clamps and Back Flow Preventor Coupler. Thing is, how do I install it on my car? Directions say to install T on inlet side of the heater (core) in order to allow back flushing. In my case, my coolant flows as such; I tapped into the inlet hose of the radiator to take coolant to the heater core then tapped into the radiator outlet hose to take the coolant away from the heater core and back to the water pump.

Would I still follow the directions on the Fill and Flush kit to allow back flushing? It would seem to me if water from the garden hose was flowing back towards the engine via the radiator inlet hose, that when the engine was running withe the garden hose also running water, the pump flow/direction and garden hose flow/direction would work against each other. The instructions state to keep the pressure cap off and perhaps that is where the pressures and flows would cancel each other?

Perhaps another approach would be... what is the best way to back flush the system in my car and with this setup?

[Mike Bellis]

I have heard of those electric pumps bottoming out in the housing and binding the impeller. Make sure to check for this. I do think it's your best be/easiest install.

If you are talking about the bottle in the trunk bubbling, that hose should connect to a filler cap vent. Should be no pressure unless your cap has failed.

[Andyrew]

I have heard of those electric pumps bottoming out in the housing and binding the impeller. Make sure to check for this. I do think it's your best be/easiest install.

Even the mopar pumps do that. I had to clearance my old rebuilt mopar pump for the impeller.

[bulitt]

Lots of threads on this topic...

[BRAVE_HELIOS]

I have heard of those electric pumps bottoming out in the housing and binding the impeller. Make sure to check for this. I do think it's your best be/easiest install.

Even the mopar pumps do that. I had to clearance my old rebuilt mopar pump for the impeller.

I was about to ask... if the Jegs unit is made to install in a stock MOPAR W/P housing and I (we) have stock MOPAR mechanical W/P installed in the Renegade Remote W/P housing, how could they not either be interchangeable (both work correctly) or both have the same potential clearance issues.

How does one check for clearance anyway?

[BRAVE_HELIOS]

Lots of threads on this topic...

Oh yes; I know and it's still very confusing... perhaps too much info out there.

I am looking for the most up-to-date info y'all have!

[914GT]

An expansion tank and overflow tank are different things. The expansion tank is pressurized and should be the highest point in your system, usually above the thermostat. The radiator cap is on this tank and it opens to purge out trapped air and coolant to the recovery tank.

I use a Dendenbear remote pump and water header like shown in the picture above. I don't know about the pump you are using but it should be probably be bench tested to make sure there's no interference with the impeller. With these electric pumps it's recommended not to use any teflon thread tape and also be careful that excess Permatex or sealants do not get into the impeller that could jam it up.

[BRAVE_HELIOS]

An expansion tank and overflow tank are different things. The expansion tank is pressurized and should be the highest point in your system, usually above the thermostat. The radiator cap is on this tank and it opens to purge out trapped air and coolant to the recovery tank.

I use a Dendenbear remote pump and water header like shown in the picture above. I don't know about the pump you are using but it should be probably be bench tested to make sure there's no interference with the impeller. With these electric pumps it's recommended not to use any teflon thread tape and also be careful that excess Permatex or sealants do not get into the impeller that could jam it up.

My expansion tank (VW Passat unit with pressure cap) is mounted above the T-stat. Pressure cap is new. Please note picture with descriptions as to which ports on the expansion tank go to where. I am pretty sure it is plumbed correctly. Not sure about the 90 degree elbows used for clearance and so rubber hoses will not kink.

Does the Dendenbear unit allow for coolant bypass when cold? Mine is a Renegade kit, therefore it has two separate ports and hoses going to those inlets.

I see... mount the pump in the housing and rotate to check for metal to metal sounds etc...

[Andyrew]

I have heard of those electric pumps bottoming out in the housing and binding the impeller. Make sure to check for this. I do think it's your best be/easiest install.

Even the mopar pumps do that. I had to clearance my old rebuilt mopar pump for the impeller.

I was about to ask... if the Jegs unit is made to install in a stock MOPAR W/P housing and I (we) have stock MOPAR mechanical W/P installed in the Renegade Remote W/P housing, how could they not either be interchangeable (both work correctly) or both have the same potential clearance issues.

How does one check for clearance anyway?

Check for clearance by installing it and seeing if it spins freely. If its difficult to bolt down tight then there is another sign.

[BRAVE_HELIOS]

I have heard of those electric pumps bottoming out in the housing and binding the impeller. Make sure to check for this. I do think it's your best be/easiest install.

Even the mopar pumps do that. I had to clearance my old rebuilt mopar pump for the impeller.

I was about to ask... if the Jegs unit is made to install in a stock MOPAR W/P housing and I (we) have stock MOPAR mechanical W/P installed in the Renegade Remote W/P housing, how could they not either be interchangeable (both work correctly) or both have the same potential clearance issues.

How does one check for clearance anyway?

Check for clearance by installing it and seeing if it spins freely. If its difficult to bolt down tight then there is another sign.

Ok. So the idea of going with the Jegs units that mounts in the Renegade housing sounds viable? I'm sure I can file/grind at least some material off the housing for clearance without it being detrimental to either the housing or the pump; yes?

[Andyrew]

Seems like it was designed to be used as a replacement of the Mopar belt driven pump so yes I think it would make perfect sense in this application.


Scroll down and you can see the issue I had with the rebuilt pump I had.
http://www.914world.com/bbs2/index.php?sho...14780&st=20

[BIGKAT_83]

I hope you have the hose from the header tank going to bottom of the recovery tank. I cant see it in your pictures. If its going to the top as it looks like there is no way for the water to get sucked back into the system.
I have a Meziere 316 55gpm remote pump I could send you to try. I would be a little harder to plump up but might save you from buying something you don't need.

[914GT]

It's not clear to me where the radiator pressure cap is. I guess the Passat tank looks more like a coolant recovery tank to me. None of the remote water pumps, electric or mechanical, are going to have a bypass like the stock pump has. You'd need a pump that mates to the holes on the block, which means modifying the firewall for clearance to the pump. I have an external bypass incorporated into my heater hose connections to give some coolant flow when the thermostat is closed. I found that the bypass keeps the engine cooler because it allows coolant to circulate in the block and heads until the thermostat needs to open up.

[BRAVE_HELIOS]

I hope you have the hose from the header tank going to bottom of the recovery tank. I cant see it in your pictures. If its going to the top as it looks like there is no way for the water to get sucked back into the system.
I have a Meziere 316 55gpm remote pump I could send you to try. I would be a little harder to plump up but might save you from buying something you don't need.

Thanks... I may take you up on the offer. I am so afraid that I will spend the money on an electric unit just to find out it is some other issue. That's why I am now cleaning out the system the best I can (without removing the engine) to see if this makes a difference. I just have had no luck with making this car remain running at a decent temp (like 180-200). I also now know to elevate the front of the car so the petcock located on the top right of the radiator can be used to bleed the system. I use a slightly modified vacuum brake fluid bleeder like this one and it works really well in helping me bleed the system.



As for the Passat header tank (I call expansion/ tank) overflow line, it does connect to the bottom of the recovery (I call overflow) tank. The recovery tank overflow line used to vent to the ground but I now have it going into another smaller bottle located at a lower point in the engine bay by the trunk bulkhead. There may be some sort of blockage there causing the header tank to build pressure. I will check it out.

[BRAVE_HELIOS]

It's not clear to me where the radiator pressure cap is. I guess the Passat tank looks more like a coolant recovery tank to me. None of the remote water pumps, electric or mechanical, are going to have a bypass like the stock pump has. You'd need a pump that mates to the holes on the block, which means modifying the firewall for clearance to the pump. I have an external bypass incorporated into my heater hose connections to give some coolant flow when the thermostat is closed. I found that the bypass keeps the engine cooler because it allows coolant to circulate in the block and heads until the thermostat needs to open up.

Yes, the VW expansion tanks utilize a pressure cap, although they are a bit problematic especially when trying to connect a pressurizing tool like the ones you can rent from your local FLAPS. I had to make an adapter in order to be able to use it.