Water pump pulley alignment
Thread Starter
8th Gear
Joined: Dec 2012
Posts: 8
Likes: 0
Water pump pulley alignment
I'm building a 383 stroker, roller cam and vortex heads for my 1978 C3 and I'm having clearance issues with my water pump pulley. I'm using a Speedway Products short water pump and a set of Aluminum CVF racing Corvette Pulleys. The water pump pulley is rubbing on the pump. I've ordered a set of shims from Summit but was wondering if anyone else has had this problem? I can't even check alignment until I can get the pulley to bolt up flush.
Any help will be greatly appreciated.
Rboz57
Any help will be greatly appreciated.
Rboz57
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
I'm building a 383 stroker, roller cam and vortex heads for my 1978 C3 and I'm having clearance issues with my water pump pulley. I'm using a Speedway Products short water pump and a set of Aluminum CVF racing Corvette Pulleys. The water pump pulley is rubbing on the pump. I've ordered a set of shims from Summit but was wondering if anyone else has had this problem? I can't even check alignment until I can get the pulley to bolt up flush.
Any help will be greatly appreciated.
Rboz57
Any help will be greatly appreciated.
Rboz57
If you're not putting the water pump pulley straight on it WILL hit the crankshaft pulley and even bind up on it. Try installing it again and make sure its going on dead straight.
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
Shimming ever so slightly will probably fix it. I have a Stewart Stage 2 pump and had a similar issue. I ended up grinding the water pump housing a small amount to clear it. Another not so good option (that I have done before) is to file or grind the back of the pulley. My .02.
Melting Slicks
Joined: Oct 2006
Posts: 2,193
Likes: 156
From: Navarre FL
Water pump pulley alignment
I have had similar issues and had to shim the pulley. I think the corvette pumps are actually slightly different than a standard short pump...so the corvette pulley with a short pump could be your issue. I don't remember where i read that fwiw
Thread Starter
8th Gear
Joined: Dec 2012
Posts: 8
Likes: 0
Shimming ever so slightly will probably fix it. I have a Stewart Stage 2 pump and had a similar issue. I ended up grinding the water pump housing a small amount to clear it. Another not so good option (that I have done before) is to file or grind the back of the pulley. My .02.
Thread Starter
8th Gear
Joined: Dec 2012
Posts: 8
Likes: 0
Thanks, I'll check on that.
Thread Starter
8th Gear
Joined: Dec 2012
Posts: 8
Likes: 0
It clears the crankshaft pulley with no problem, it does hit the water pump housing before sitting flush. Once I shim it and bolt it down, I'll be able to check alignment. I'm going with electric fans so if I need to shim the dampener on the crank, I can do that too. I'll post a photo after I get the shims installed. Thanks.
Instructor
Joined: Feb 2006
Posts: 118
Likes: 25
From: Killearn Scotland
The Corvette pump is different, see below:
Long Chevy Pump = 5/8" pilot diameter & 6-15/16" block to hub distance
Short Chevy Pump = 5/8" pilot diameter & 5-5/8" block to hub distance
Corvette Pump = 3/4" pilot diameter & 5-13/16" block to hub distance
So a 3/16" spacer will put your pulley back where it should be. So long as the crank pulley's are still original, or if they are new, that they are in the original position, then you should get true belt alignment.
The pilot stub will be smaller though, and this helps ensure the pulley is central on the pump. If you have an aftermarket pulley, then the pilot hole will probably be the smaller 5/8" size. The original Corvette pulley will have a larger hole than the pilot.
You can also get aftermarket pumps (including aluminium ones) with the original Corvette specific dimensions.
Long Chevy Pump = 5/8" pilot diameter & 6-15/16" block to hub distance
Short Chevy Pump = 5/8" pilot diameter & 5-5/8" block to hub distance
Corvette Pump = 3/4" pilot diameter & 5-13/16" block to hub distance
So a 3/16" spacer will put your pulley back where it should be. So long as the crank pulley's are still original, or if they are new, that they are in the original position, then you should get true belt alignment.
The pilot stub will be smaller though, and this helps ensure the pulley is central on the pump. If you have an aftermarket pulley, then the pilot hole will probably be the smaller 5/8" size. The original Corvette pulley will have a larger hole than the pilot.
You can also get aftermarket pumps (including aluminium ones) with the original Corvette specific dimensions.
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Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
Start with the smallest shim in the kit that you ordered. Increase in thickness until you clear the pump. Make sure that your pulleys are aligned after shimming. If shimming throws the pulley alignment off too much you will have to resort to one of the other methods.
Melting Slicks
Joined: Oct 2006
Posts: 2,193
Likes: 156
From: Navarre FL
The Corvette pump is different, see below:
Long Chevy Pump = 5/8" pilot diameter & 6-15/16" block to hub distance
Short Chevy Pump = 5/8" pilot diameter & 5-5/8" block to hub distance
Corvette Pump = 3/4" pilot diameter & 5-13/16" block to hub distance
So a 3/16" spacer will put your pulley back where it should be. So long as the crank pulley's are still original, or if they are new, that they are in the original position, then you should get true belt alignment.
The pilot stub will be smaller though, and this helps ensure the pulley is central on the pump. If you have an aftermarket pulley, then the pilot hole will probably be the smaller 5/8" size. The original Corvette pulley will have a larger hole than the pilot.
You can also get aftermarket pumps (including aluminium ones) with the original Corvette specific dimensions.
Long Chevy Pump = 5/8" pilot diameter & 6-15/16" block to hub distance
Short Chevy Pump = 5/8" pilot diameter & 5-5/8" block to hub distance
Corvette Pump = 3/4" pilot diameter & 5-13/16" block to hub distance
So a 3/16" spacer will put your pulley back where it should be. So long as the crank pulley's are still original, or if they are new, that they are in the original position, then you should get true belt alignment.
The pilot stub will be smaller though, and this helps ensure the pulley is central on the pump. If you have an aftermarket pulley, then the pilot hole will probably be the smaller 5/8" size. The original Corvette pulley will have a larger hole than the pilot.
You can also get aftermarket pumps (including aluminium ones) with the original Corvette specific dimensions.
OP...just get a pulley for a regular swp. It should fix your problem. I an running that setup with no problems. PS pulley should bee close enough that it won't be a problem...i should mention that i an also using a swp alt bracket.
Melting Slicks
Joined: Oct 2001
Posts: 2,064
Likes: 1,382
From: Halifax, Nova Scotia, Canada
The Corvette pump is different, see below:
Long Chevy Pump = 5/8" pilot diameter & 6-15/16" block to hub distance
Short Chevy Pump = 5/8" pilot diameter & 5-5/8" block to hub distance
Corvette Pump = 3/4" pilot diameter & 5-13/16" block to hub distance
So a 3/16" spacer will put your pulley back where it should be. So long as the crank pulley's are still original, or if they are new, that they are in the original position, then you should get true belt alignment.
The pilot stub will be smaller though, and this helps ensure the pulley is central on the pump. If you have an aftermarket pulley, then the pilot hole will probably be the smaller 5/8" size. The original Corvette pulley will have a larger hole than the pilot.
You can also get aftermarket pumps (including aluminium ones) with the original Corvette specific dimensions.
Long Chevy Pump = 5/8" pilot diameter & 6-15/16" block to hub distance
Short Chevy Pump = 5/8" pilot diameter & 5-5/8" block to hub distance
Corvette Pump = 3/4" pilot diameter & 5-13/16" block to hub distance
So a 3/16" spacer will put your pulley back where it should be. So long as the crank pulley's are still original, or if they are new, that they are in the original position, then you should get true belt alignment.
The pilot stub will be smaller though, and this helps ensure the pulley is central on the pump. If you have an aftermarket pulley, then the pilot hole will probably be the smaller 5/8" size. The original Corvette pulley will have a larger hole than the pilot.
You can also get aftermarket pumps (including aluminium ones) with the original Corvette specific dimensions.
'70 and older use 5/8" pilot pumps.
In '71 the pump bearing size was increased.
Thread Starter
8th Gear
Joined: Dec 2012
Posts: 8
Likes: 0
The Corvette pump is different, see below:
Long Chevy Pump = 5/8" pilot diameter & 6-15/16" block to hub distance
Short Chevy Pump = 5/8" pilot diameter & 5-5/8" block to hub distance
Corvette Pump = 3/4" pilot diameter & 5-13/16" block to hub distance
So a 3/16" spacer will put your pulley back where it should be. So long as the crank pulley's are still original, or if they are new, that they are in the original position, then you should get true belt alignment.
The pilot stub will be smaller though, and this helps ensure the pulley is central on the pump. If you have an aftermarket pulley, then the pilot hole will probably be the smaller 5/8" size. The original Corvette pulley will have a larger hole than the pilot.
You can also get aftermarket pumps (including aluminium ones) with the original Corvette specific dimensions.
Long Chevy Pump = 5/8" pilot diameter & 6-15/16" block to hub distance
Short Chevy Pump = 5/8" pilot diameter & 5-5/8" block to hub distance
Corvette Pump = 3/4" pilot diameter & 5-13/16" block to hub distance
So a 3/16" spacer will put your pulley back where it should be. So long as the crank pulley's are still original, or if they are new, that they are in the original position, then you should get true belt alignment.
The pilot stub will be smaller though, and this helps ensure the pulley is central on the pump. If you have an aftermarket pulley, then the pilot hole will probably be the smaller 5/8" size. The original Corvette pulley will have a larger hole than the pilot.
You can also get aftermarket pumps (including aluminium ones) with the original Corvette specific dimensions.
The 3/16 spacer put the pulley in the correct alignment. Went together with no problems. Thanks everyone for your comments!
Rboz