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the 70 threw the belt... water pump pulley wobbles like a moe...
this is the base zq3 300hp 350cu engine... it has not been out and has not been apart except it has replacement water pump and alternator from years ago...
looking for advice as i only want to do this once... what say you...
Are you sure it's the pump's shaft that's causing the wobble?
Where are you seeing the wobble - the pulley itself or the fan blades? The blades are easily bent out of plane which would appear as a wobble. Maybe when the belt let go?
Do you care about originality? Pumps can be rebuilt or purchased from a place like Chevy Cool in Phoenix.
I've had the Stewart stage 1 pump in my car for over 20 years with no problems. The only issue is the shaft is 3/4 instead of 5/8. You just need to make the hole in the pulley a little bigger.
three weeks ago i heard a high pitched zing above 4000 rpm... the belt had flipped notched side out... put new belt on and the zing was no more...
this week i hear the zing again above 4k... thought it was the new belt... then it threw it off...
the fan blade and pulley assembly moves up and down when i grab it... with the belt back on and idling i can clearly see a wobble in the pulley and everything from the pulley forward...
on the way home the high pitched zing was at 2500 rpm... so i kept it below 2.5k...
fingered it was the bearing but it may not be that after all...
three weeks ago i heard a high pitched zing above 4000 rpm... the belt had flipped notched side out... put new belt on and the zing was no more...
this week i hear the zing again above 4k... thought it was the new belt... then it threw it off...
the fan blade and pulley assembly moves up and down when i grab it... with the belt back on and idling i can clearly see a wobble in the pulley and everything from the pulley forward...
on the way home the high pitched zing was at 2500 rpm... so i kept it below 2.5k...
fingered it was the bearing but it may not be that after all...
johnny
If you can feel looseness in the pump shaft when the pulley and fan clutch bolts are tight, then I'd say it's time for a new pump. If you remove everything from the pump you may be able to feel roughness in the bearing as you spin the shaft.
Is this belt running an AC compressor? Are you positive it's in alignment with the pump's pulley? (This is could be a separate issue from pump wobble, but it's throwing belts for some reason.)
I am surprised you did not send the shroud to the scrap pile.
I'm too tired to click on all those pumps you listed.
However, make sure the listing is Corvette Specific.
They are not a std short W.P.
Nor are they a std long W.P.
They are a Corvette pump.
Yup, a lot of people think there are 2 Chevy small block water pumps. Short nose and long nose.
Guess they don't understand that Corvette's are a different animal.
There is indeed a third SBC water pump. The Corvette pump.
im aware there are short and long and corvette pumps... was under the impression the corvette pump is a shorty with a 5/8 shaft compared to non corvette pumps being 9/16 shaft... then 3/4 later years...
pulling it off tomorrow... since the po replaced the water pump and fan clutch years ago im not sure what is in there... but will get a corvette pump on there for sure...
There were some valuable drawings on the forum years ago showing the measurements of the three pumps.
Not only the distance between the timing cover and the back of the pump, but also how far out the fan mount hub stuck out.
And the pilot shaft, etc.
Years ago, I spotted a chrome W.P. pulley at the store. Claimed it fits all SBC from blah-blah-blah to ??????
Well, bought it, tried it, my W.P. bolt pattern was different too.
70 Water Pump
