1981 Corvette Water Pump Replacement
Thread Starter
Navigator
Joined: Sep 2010
Posts: 9
Likes: 0
From: Mineola NY
1981 Corvette Water Pump Replacement
Hi. This is my first post. I have a 1981 Corvette coupe with the L-81 motor. All original equipment is in tact including the pollution control pump. I am replacing my water pump and in doing so I cannot find one with the proper fitment. I have purchased several already and I find that the left side bolt sleeves are too long, there is not enough neck clearance, or the lower radiator hose outlet rubs the back of the pulleys when installed. I have the ability to machine the pump, but what happened to good old replacement. Has anyone experienced this or is it just me. I could simply remove the A.I.R. pump, but then I would no longer consider my car 100% original. Any thoughts would be appreciated.
Dave
Dave
Drifting
Joined: Apr 2006
Posts: 1,911
Likes: 2
From: gold coast queensland
there is corvette specific pumps available but thats more to do with the different size shaft that suits your corvette pulley. 99 % of pumps should have little difference in the casting that a different size bolt should fix so sounds like you have been unlucky. I have an 81 and did not like the corvette specific pump or pulleys so changed them out for a weeiand pump and pulleys that suited my taste that gave me greater options in styles . alot cheaper too.
i would be taking your old pump with you so you can measure up the differences at the shop .
i would be taking your old pump with you so you can measure up the differences at the shop .
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
This arises with aftermarket alum pumps often.
1st make sure you really have the correct pump for your application, maybe try another again (as is different manufacturer).
Usually the pulley interference is at the heater hose connection boss, not lower hose area, and that can be ground down to fit, enough meat there.
If using the oem a/c mount brackets and air pump etc, then you will have to mill the boss down for that or break the cast mount. I've had to go as much as approx 1/8". Other than that the short and the corvette pump are the same for lower rad hose position and angle.
Pump should have 3/4 shaft and 5.795" from block face to clutch mount face. Check to make sure clutch mount flange isn't pressed on shaft too deep first.
1st make sure you really have the correct pump for your application, maybe try another again (as is different manufacturer).
Usually the pulley interference is at the heater hose connection boss, not lower hose area, and that can be ground down to fit, enough meat there.
If using the oem a/c mount brackets and air pump etc, then you will have to mill the boss down for that or break the cast mount. I've had to go as much as approx 1/8". Other than that the short and the corvette pump are the same for lower rad hose position and angle.
Pump should have 3/4 shaft and 5.795" from block face to clutch mount face. Check to make sure clutch mount flange isn't pressed on shaft too deep first.
Racer
Joined: Nov 2000
Posts: 290
Likes: 0
From: Omaha, NE
Try to get a GM casting # 330 813 or 330 818 pump. They were for 71-82 corvette and some medium duty trucks. Rebuilts are sometimes listed on ebay for $99. The new aftermarket castings can be problematic as you describe. Good luck.
Burning Brakes
Joined: Aug 2006
Posts: 1,058
Likes: 27
From: Eastern North Carolina
I purchased a new pump for $40.00 from AdvanceAuto parts about a year ago and it fit perfect. It may not be a original pump but it works well and lets me drive my car instead of looking at it.
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
Not sure about '81s, but the short Corvette water pump with the 3/4" shaft is not the same length as the short Chevy water pump which was used for many years - the Corvette short pump is 3/16 longer from the block to the pulley flange. If you are in this predicament, usage of a 3/16 thick spacer between the flange and the water pump pulley will allow the pulley to align and the pulley not to rub. This assumes that the pump has been rebuilt correctly and is either 5 13/16" or 5 5/8" from the block mounting surface to the pulley flange, depending on Corvette or short Chevy WP.
Pro
Joined: Feb 2003
Posts: 582
Likes: 0
From: Ashaway RI
Stewart stage 1 water pump - perfect fit, no modifications required.
http://www.stewartcomponents.net/Mer...y_Code=ChevyS1
http://www.stewartcomponents.net/Mer...y_Code=ChevyS1
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Thread Starter
Navigator
Joined: Sep 2010
Posts: 9
Likes: 0
From: Mineola NY
Sorry I have not been on sooner. Just wanted to updaye you that a Cardone pump was the perfect replacement. I also sent my original pump out for rebuild and will keep it for future use. Thanks for all the advice.
