Thickness of water pump gasket??

[ShawnZR-1]

Ok, so I put the new water pump on and torque the bolts down. Go to spin the pulley and it won't budge at all!

So, I take it all back apart and put the old and new side by side on the bench. The impeller is within 1/32" but the gasket thickness between what was on there and what was included with the new pump is 1/16" thinner on the new one!

I pulled a spare gasket down and it's just a bit thicker than the new one but still thinner than the original.

Anyone know what the original ACDelco gasket's thickness is? :dontknow::dontknow:

[ShawnZR-1]

Are those ACDelco gaskets?

It looks like the one on there is 3/32" (compressed). .09" is twice the thickness of yours.

[Scrrem]

I'm getting ready to do the water pump on mine. When I get home tonight I will have to measure the gasket that came in the box.

Rich

[ShawnZR-1]

Scrrem, is your pump an AC Delco also?

[Scrrem]

Scrrem, is your pump an AC Delco also?

Not sure. It's a rebuilt unit, is there a way to distinguish an AC Delco unit?
Rich

[A26B]

.... So, I take it all back apart and put the old and new side by side on the bench. The impeller is within 1/32" .........

You mentioned that this is a rebuilt pump. What dimension are you referring to that is within 1/32"?

Here are dimensions taken from a used, OEM pump. Measure yours & maybe we can locate the problem. With rebuilt pumps, there are an array of possibilities that could cause the pump to bind on installation. Once rebuilt, it no longer matters if it says AC Delco on the pump.

A. diameter of the impeller : 3.857"
B. height from pump flange to back of the impeller : 0.175"
D. height of impeller hub from back of impeller : 0.160"
E. used oem pump gasket : 0.044" current thickness (note, new gaskets will compress when installed and have some "rebound" when removed) est uncompressed thickness, 0.049". Compression & rebound depends on the composition of the gasket material.

Jerry

[A26B]

Jerry....my micrometer does work perfectly I guess :sign10:
He said his original gasket was .093 so that confuses me.

Yes, 0.093" is probably erroneous. Used gaskets usually have a portion that is outside the parts face and doesn't compress and swells up. If you don't isolate that portion when measuring, you get a bad reading.

I think the problem is going to be in the rebuilt pump.

[ShawnZR-1]

My .093" is as close as I could measure because it's still stuck to the old pump. I can't mic it. I can't remove the gasket because it just deteriorates in my hand.

I'll get more accurate measurements tonight when I get back home.

I appreciate all the help guys! I just want to isolate where the problem is. By the sounds of Dynomite's dry fit of his pump, it is looking like mine is way out of tolerance.

[phrogs]

does your pump spin freely in your hand?

Im sure it does but when you installed it the propeller is binding against the front engine cover so thats a problem, perhaps it wasnt pressed all the way on and is sticking out jut enough. Its a tight fit in there anyway.

[ShawnZR-1]

It does spin in my hand, just when it's torqued to the engine, it seizes up. If I loosen the bolts and spin it, it scrapes against the block. Something ain't right with it!

[lbszr]

I had the exact problem a couple of years ago. When the pump was toqued down, the housing's flange tabs were visibly bent and I can't believe they didn't snap off. The pump was from smyths, it was a rebuild from a popular rebuild that does sbc's. I can't remember what it was, would remember it if heard it though. The impeller was not close to the quality of a ac delco. The impeller looked like it was from a rough cast, as ac delco looked like a forging, and perfect. I don't have the measurements any more, but I remember the rebuild's impeller measured thicker than the ac delco and could not be pressed on any farther. The one I had was way out, four gaskets might of fixed it if leaks weren't an issure. I thought of it as..... if least somebody is trying to make one fit, and it could fit after removing it and remachining it, then it could be an option when ac's aren't available.

[tomtom72]

I know that this might not be of any use Shawn. I seem to remember Marc Haibeck doing a paper on re-built LT5 pumps and this very issue, impellar binding upon T/Q'ing it in place.

I just can't remember if it was in an issue of HOTB or a paper over at his site. I know I read it and thought that I should buy a OE replacement pump now ( back in '06 ) instead of waiting till my pump went south.

Sorry i can't be of more help.:o

Merry Christmas!
:cheers:
Tom

[ShawnZR-1]

It's the fecking impeller! It's warped... worse than me!

Ok, I'm done with "reman", biting the bullet!

[Scrrem]

It's the fecking impeller! It's warped... worse than me!

Ok, I'm done with "reman", biting the bullet!

Wow, just checked my "reman" pump, looks like mine is OK..crossing my fingers

[ShawnZR-1]

Hey Scrrem, where did you get your reman'd pump? I'm having more difficulty finding someone that has a NOS AC Delco in stock for less than $400. Sorry, that number is just insane!

[ShawnZR-1]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=400056901283&viewitem=&sspagename=STRK%3AMEWNX%3AIT

With gasket and it all fits perfectly :cheers:

Sonofabitch! I checked ebay and searched on ZR-1 because ZR1 returned a thousand hits!

Thanks! I'll order up in the morning! :handshak:

[A26B]

I have 5 left, but they are $320. New, OEM AC Delco. They are on the web site.

[Scrrem]

Hey Scrrem, where did you get your reman'd pump? I'm having more difficulty finding someone that has a NOS AC Delco in stock for less than $400. Sorry, that number is just insane!

Bought it a few weeks ago from a felllow member here in VA. The pump is in a NAPA box, hoping it installs with no issues.

Rich

[Jagdpanzer]

Here is another source for LT5 water pumps:

http://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50000050f~Z5Z5Z5AATSH~ P199.00~~~~S2TT103BPC20518866724d~Z5Z5Z5~Z5Z5Z5000 0050F
http://www.parts123.com/parts123/yb.dll?parta~showpic~Z5Z5Z50000050f~Z5Z5Z5AAOSF~Z5 Z5Z5~Z5Z5Z5~Z5Z5Z5

[ShawnZR-1]

:thumbsup: Nice! Do we know if that's reman'd? They're closed until next year... if I don't have a suitable replacement by then, I'll order from Corvette Central!

[ShawnZR-1]

I actually have a spare gasket from a kit I ordered a couple of years ago when I did my head gasket R/R. Thanks for the reminder though!!

[zr1343]

I hit the same thing a year ago when I replaced my water pump. It ended up being the actual impeller was not on the shaft properly. It was a royal PITA. I had to remove and return and get another and install.

[Scrrem]

Bought it a few weeks ago from a felllow member here in VA. The pump is in a NAPA box, hoping it installs with no issues.

Rich

Well, Just got home from a failed attempt to swap out my water pump. The rebuilt pump impeller was not pressed on the shaft deep enough. This caused the same issue as in previous posts in this tread regarding the impeller hitting the block and not allowing the pump body to seat to the block. Just a word of caution, to anyone considering a rebuilt water pump, be careful. Going in search of an AC Delco now.
Rich

[ShawnZR-1]

Well, I decided to go the "reman" route one more time and bought one from H2OPumpMan on eBay. The impeller looks perfect and it came with the correct gasket with the bead on it. I installed it today and am ecstatic to say, it's perfect! The beast is back!