Pulley Geometry
Thread Starter
Burning Brakes
Joined: Apr 2007
Posts: 1,028
Likes: 1
From: SOUTH ELGIN IL
Pulley Geometry
While I am installing my new DeWitts I purchased a new Edelbrock short water pump with a 5/8" pilot. Of course my water pump pulley is 3/4" so I need to buy a new one - which I was going to do anyway. Since I'm doing that I figure I'll get a new polished crank pulley too. Problem is that I have a double groove crank pulley with another slightly smaller diameter single mounted to it, effectively making it a 3 groove. My power steering pump lines up with the outside most groove on my "3 Groove" crank pulley. All the short water pump crank pulleys I have seen at Summit, etc are 2 groove, 3 grooves are only available in the long neck water pump section.
Should I get the 3 groove?
I should mention I am currently running a ZZ4.
EDIT: I see now that the second pulley is the "power steering add on pulley" on corvettecentral.com. Doesn't seem to come polished so I still need a strategy...
Thanks,
Dan
Should I get the 3 groove?
I should mention I am currently running a ZZ4.
EDIT: I see now that the second pulley is the "power steering add on pulley" on corvettecentral.com. Doesn't seem to come polished so I still need a strategy...
Thanks,
Dan
Last edited by Dantana; Aug 30, 2009 at 05:36 PM.
Former Vendor
Joined: Apr 2009
Posts: 766
Likes: 3
From: Charlotte North Carolina 704-394-5150
My best advice is to be careful in changing the diameters and offsets of the water pump pulley to much because it can cause the water flow charastics to change and possibly cause the water to circulate faster than you may want and cause for heat issues due to the water is not able to stay in the radiator long enough to cool down....due to this inceased flow....along with trying to make the power steering pulley line up. BEEN THERE...DONE THAT...
I always hate when I have to fix a car that has different pulleys on them because....it is want it is... and when you drastically change flow, it is often times extremely hard to correct without putting the correct pulleys back on the engine. I have had a sleeve machined to take up the difference..but that was also using the clutch fan assembly.... and factory water pump pulley.
Just check your water flow at idle and make sure it is not flowing to fast. Best of luck and that is the only advice I can give...unless you find a company that can deal with your issues. Trying to find parts from different manufacturers is always a pain for me also...sometimes they work...sometimes they do not.. but nonetheless...it is time consuming.
"DUB"
I always hate when I have to fix a car that has different pulleys on them because....it is want it is... and when you drastically change flow, it is often times extremely hard to correct without putting the correct pulleys back on the engine. I have had a sleeve machined to take up the difference..but that was also using the clutch fan assembly.... and factory water pump pulley.
Just check your water flow at idle and make sure it is not flowing to fast. Best of luck and that is the only advice I can give...unless you find a company that can deal with your issues. Trying to find parts from different manufacturers is always a pain for me also...sometimes they work...sometimes they do not.. but nonetheless...it is time consuming.
"DUB"
Safety Car
Joined: Oct 2004
Posts: 3,920
Likes: 731
From: Youngstown Ohio
Pulley Setup
Here are some pics of my pulley setup....they are aftermarket, and the crank pulley is 3 groove; it is also smaller diameter than stock for 25% underdrive of all accessories. The outermost groove will align correctly with the P/S pump. I bought it years ago, from P.A.W. Parts.....I believe it's still available, about 5 1/4" diam., aluminum.
Drifting
Joined: Jul 2005
Posts: 1,562
Likes: 2
From: Spring Texas
You have the wrong waterpump. The Corvette waterpump is a "short" waterpump, but there is more than the shaft size to differentiate it from a standard chevy short pump. The correct Corvette Pump is slightly longer (1/4" I think) than the standard short Chevy pump.
Get the correct waterpump and use your oeiginal pulleys. If you want to upgrade to shiny bling pulleys, March Performance has Corvette specific billet alumininum pulleys, or you can buy chromed pulleys from many of the forum sponsor/vendors.
Get the correct waterpump and use your oeiginal pulleys. If you want to upgrade to shiny bling pulleys, March Performance has Corvette specific billet alumininum pulleys, or you can buy chromed pulleys from many of the forum sponsor/vendors.
Thread Starter
Burning Brakes
Joined: Apr 2007
Posts: 1,028
Likes: 1
From: SOUTH ELGIN IL
can anyone please comment on if I really need corvette specific pulleys and water pump anymore? I told Edelbrock what I had and they sent me this short neck pump. Assuming it is incorrect I have no AC and am running GM ZZ4 crate (not corvette specific). Any reason why I can't just go with any other normal set up for the front of a small block chevy?
I'm very interested in responses. Thanks.
I'm very interested in responses. Thanks.
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Information for the correct pump for your car/engine (stock):
Short Style Pump for 1971-76 Corvettes (.750" pilot shaft)
Fits all 1971-76 small block Corvettes.
Has heavy duty .750" ball/roller bearing.
Dimension from block surface to hub 5.812". Inlet diameter 1.80"
So if you are using the original pulleys, then this is what you need. If you are NOT using original pulleys, then use whatever you want as long as the grooves all line up correctly.
Short Style Pump for 1971-76 Corvettes (.750" pilot shaft)
Fits all 1971-76 small block Corvettes.
Has heavy duty .750" ball/roller bearing.
Dimension from block surface to hub 5.812". Inlet diameter 1.80"
So if you are using the original pulleys, then this is what you need. If you are NOT using original pulleys, then use whatever you want as long as the grooves all line up correctly.
Last edited by pws69; Aug 31, 2009 at 12:14 PM.
Thread Starter
Burning Brakes
Joined: Apr 2007
Posts: 1,028
Likes: 1
From: SOUTH ELGIN IL
Information for the correct pump for your car/engine (stock):
Short Style Pump for 1971-76 Corvettes (.750" pilot shaft)
Fits all 1971-76 small block Corvettes.
Has heavy duty .750" ball/roller bearing.
Dimension from block surface to hub 5.812". Inlet diameter 1.80"
So if you are using the original pulleys, then this is what you need. If you are NOT using original pulleys, then use whatever you want as long as the grooves all line up correctly.
Short Style Pump for 1971-76 Corvettes (.750" pilot shaft)
Fits all 1971-76 small block Corvettes.
Has heavy duty .750" ball/roller bearing.
Dimension from block surface to hub 5.812". Inlet diameter 1.80"
So if you are using the original pulleys, then this is what you need. If you are NOT using original pulleys, then use whatever you want as long as the grooves all line up correctly.
Safety Car
Joined: Oct 2004
Posts: 3,920
Likes: 731
From: Youngstown Ohio
can anyone please comment on if I really need corvette specific pulleys and water pump anymore? I told Edelbrock what I had and they sent me this short neck pump. Assuming it is incorrect I have no AC and am running GM ZZ4 crate (not corvette specific). Any reason why I can't just go with any other normal set up for the front of a small block chevy?
I'm very interested in responses. Thanks.
I'm very interested in responses. Thanks.
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