Electric Water Pump Swap for LT1

So my water pump started leaking coolant onto the Opti and I let her sit for a couple of days trying to decide whether I wanted to rebuild/replace the stock pump or go Meziere. A little perusing of the F-Body and Vette Forums and the pro's so outweighed the cons that I decided to do the swap.

1st off, I discovered while price-comparing that Jegs has a pump with the same performance as the Meziers, at half the price and with a good warranty, so after talking with their technical guys (who assured me that they have had no problems reported so far with them) and with Gary @ Innovative Wiring, who could supply me with his "as-always" top quality installation kit, complete with a receiver plug for the Jegs pump, I went with Jegs rather than Meziere.

The pump seems to be extremely high-quality and has a billet mounting flange with a built-in o-ring, so no gasket or ultra was needed.

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Step 1 (after removal of the pump from the car) is "Press shaft from pump". This is accomplished in a variety of ways in different write-ups. I had BrokeCello on chat the first night, so felt good about the small-sledge and 5/16" bolt method, but was pounding harder than I felt comfortable with and failed with my small shop vices and C-clamp tries as well, woke up the next morning and jury-rigged a press, floor-jacking the wagon up, supporting its weight on a scissor jack and then using it's frame rail as a press beam to push the bolt through. Another fail, and I should have taken pictures. You'll have to trust me that a 2-ton wagon looks lighter than I know it is when its wheels are off the ground and its weight is being supported by a 5/16 x 3" bolt on top of a water pump. Took it to a buddy's hous a couple of blocks away and "POP!", it came right out with a 30-ton hydraulic press.

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I cleaned the inside out with a wire brush (and am damned lucky I replaced it when I did, as the bearing was shot), and pressed the (included with pump) plug with a hammer and deep socket (you can't see it, but there's a bit of ulra-black on the plug, just to be sure it doesn't leak).

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It's woth noting that after I pulled the shaft and bearing, there was a ring/ridge in th opening that I need to remove with a flat-bladed screwdriver and ballpeen. It came out fairly easily, but would have prevented the plug from sitting flush.

I've read about people removing the drive cog, but on Chris' advice, mine's still back there, whirring away. I may weld up the hole or something if I've ever a need to replace/upgrade the timing chain.

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The pump went on without issue, though this step was the longest and most arduous (cleaning off the previous gaskets, accomplished with Permatex remover,  a razor blade and a followup with a wirewheel. I hate gasket cleanup.

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Bad picture, but Gary's harness is (as they all are) extremely high quality and looks factory installed. The pump's driven off of the airpump circuit, so turns on with the key. It includes an extra dongle for Tom's mod ( a light and/or buzzer in the dash in case of failure) and I had anticipated this mod down the pike when I designed my cluster (so have a "Water Pump" idiot light already, just waiting for me to wire it).

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I've been driving for two days now without issue. All said, not a bad way to spend a Saturday morning (and a bit of Friday night).

Great modification and the water pump failure light is a good idea too.Always wondered how this electric pump wii compare to the engine driven pump on a really hot day in stop and go traffic.Think it would actually move more water than the engine driven pump?Please show us how that cluster mounted warning looks when on.Notice I didnt call it a idiot light?

Modern world.   They have electric a/c compressors, electric power steering, and electric water pumps now.  

I'm becoming an old man. 

I don't even like electric fuel pumps, which have been out for 30+ years.   To me...I still don't trust electric motors.   Been stranded from dead electric fuel pumps (Denali), had cars overheat because their electric engine fans fail to come on (Citation X-11, '86 Iroc-Z, 1996 Pontiac Bonneville)....and been roasted when blower motors have failed on 100-degree days ('78 Impala), and of course, have watched power window motors get slow and finally fail over time (too many cars to count).

Yes I know these modern electric motors are well tested and designed to run forever....and they may.   I just remember paying $15 for a new mechanical fuel pump on my '83 Bonneville (car still ran, pump just leaking) and replacing it in 20-mins.....and $25 for the water pump on my '78 Silverado (ditto, still ran,seal just seeping), and replacing it in less than an hour.   

My most recent electric motor experience was paying $250 for the in-tank fuel pump on my Denali...and it being a 2-day nightmare to replace in the driveway.   

Sometimes progress is not cheap....or easy to replace.  

Good luck with it! 

-Mike

FlashGumby wrote:

Step 1 (after removal of the pump from the car) is "Press shaft from pump". This is accomplished in a variety of ways in different write-ups. I had BrokeCello on chat the first night, so felt good about the small-sledge and 5/16" bolt method, but was pounding harder than I felt comfortable with and failed with my small shop vices and C-clamp tries as well...

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I cleaned the inside out with a wire brush (and am damned lucky I replaced it when I did, as the bearing was shot)

 Well, that explains why it was a bugger to get out! I bet it was semi fuzed due to the bad bearing/heat/friction! 

 Glad you got it done....I am very interested in doing this again now! (but with the same pump you bought)  That is a heck of a price break AND you can get the connector setup from Gary.  Very nice!

I hemmed and hawed a bit, Mike. Although I have had cars with (electric) fuel pumps more than 50 years old in them that worked fine (SU's used electric since '26), mechanical's usually the way to go.

The LT1's water pump is an exception. Like electric motors, seals and bearings do go eventually. In the LT1, when the seal and/or bearing go, scalding water is dumped all over the cars electrics, distributor, plug wires and coil. When the electric motor goes, the engine overheats. In this odd case, the possible ramifications of the eventual electric pump failure are more benign than the mechanical one's, and the electric motor swap is a 10 minute job which could theoretically be handled by the side of the road.

There are a lot of people racing with them in F-bodies and Vettes, Jim. It's not that they move more water. It's that they do it more efficiently. I'm pretty sure that at 6 or 7000 rpm, the mechanical's moving more than 55 GPH (which is what the electric moves no matter what the speed). The electric motor spins at a given rpm and the impeller is designed to be effective at that speed. The mechanical's impeller needs to be able to move enough water to cool the engine at idle, yet not churn at redline, so ends up being less efficient than it could be throughout the RPM range (which is one of the reasons why such unbelievable HP gain numbers can be quoted sometimes).

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-Scott McGrath
 '96 Roadmaster Estate Ltd. - Last of the Great American Wagons
Low 14's - But I've "Done some stuff to it."
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 ISSCA#2229  BCA#43406  BMD#115

FlashGumby wrote:

and the electric motor swap is a 10 minute job which could theoretically be handled by the side of the road.

IF you have another one. Every auto parts store on the continent has a listing for the stock pump.

buickwagon wrote:

FlashGumby wrote:

and the electric motor swap is a 10 minute job which could theoretically be handled by the side of the road.

IF you have another one. Every auto parts store on the continent has a listing for the stock pump.

Yep.  And I can count on one hand the number of people I've read about on the forum that have suffered a catastrophic stock waterpump failure (sheared splines or a slipping impeller.  I've personally SEEN catastrophic electric water pump failures.  I also saw the guy change it on the side of the road, but as you say, you've gotta keep a spare in the trunk.

Did not mean to knock your work.   It's a neat item and a sharp install.   I was just being my crotchety old self....bad day at work.

I wish you the best with it!

-Mike

Yeah, nice work BTW.

Nice write-up, thanks!  I had a similar setup when I had my SS, they do work well in these cars.

i know this is a old post does anyone know where i can get thewarning kit if the pump fails ? i got garys wiring kit he said he doesnt know if tom is still making the warning kit

After going through the trouble of replacing the pump, the most logical step would be to install a digital temp controller, available from several vendors. The controller gives very fine, adjustable temp control while turning the pump at no more duty than needed. The energy loss avoidance through a mechanical thermostat, as well as quicker warm-up are just some of the benefits. As far as a pump failure warning signal goes, the dash temp gage gives a really quick indication that something has gone wrong.