pulleys wont line up

[Kurt Reiter]

My crankshaft and water pump pulleys wont line up. I know I have the right pulleys, but the crankshaft pulleys are too far back and dont line up with the water pump ones. I have a '79 350 with ac.Is there a spacer that goes on the balancer between the it and the pulleys, or is my water pump too long? I have the original water pump and it is the same length. Help! thanks-

[Joe L.]

Re: pulleys wont line up

Kurt----

No spacer between the balancer and the pulley was originally used for any 1979 Corvette application. If the water pump that you are using is the same from block mating surface to face-of-hub as the original waterpump, then you must have a correct waterpump.

You didn't state whether the engine is an L-48 or an L-82; that makes a difference here. Also, you didn't state which pullies that you have or which balancer that you have. You just stated that you know that you have the right pullies. If, indeed, you have all the right parts, then there should be no problem with pulley alignment.

[Kurt Reiter]

Re: pulleys wont line up

Hey Joe- thanks again. you gave me some advice a few weeks ago about which pulleys to buy. Thats how I know I have the right ones. What I can't figure out is why the pulleys on the water pump are too far forward and dont line up- I have an L-48
Kurt

[Joe L.]

Re: pulleys wont line up

Kurt-----

That's assuming that I didn't unwittingly give you a "bum steer" on the pulley information. I usually double check AND cross check these things, so it's unlikley that it happened, but I can't say for absolute certain. So, refresh my memory as to what pullies that you have. Also, what is the thickness of the balancer that you have installed? In addition, what is the GM casting number on the water pump that you took off and have installed and the measurement from the block mounting face of the pump to the face of the water pump hub? You can get this measurement from the old pump providing that you KNOW that it's the same as the new pump.

[Kurt Reiter]

Re: pulleys wont line up

The pulleys are: pump- 2 groove 14023159 and single groove 3991425. Crank- 2 groove 14023151 and single groove 346290. My balancer is 1 3/8" thick and about 8"diameter. the Water pump stamping is CMT 7 then 3927170 then F 8 70. The pump measures 7" from base to spindle face.

[Joe L.]

Re: pulleys wont line up

Kurt-----

Now I know EXACTLY what your problem is. You are using a LONG LEG style waterpump. That's what the GM #3927170 casting is. Long leg waterpumps were NEVER, EVER used on Corvettes although many "parts counter guys" seem to think so. The long leg style waterpumps were used on most 1969 and later small blocks EXCEPT Corvettes. 69-70 Corvettes (as wll as all earlier Corvette small blocks) used the short leg style waterpump also used for most 1968 and older small blocks across the Chevrolet line. 1971-82 Corvette small blocks use a unique-to-Corvette (and HD truck) waterpump. This pump has a block-to-hub face measurement which is a little greater than the 55-70 Corvette short leg water pump, but MUCH less than the long leg style waterpump. The 71-82 Corvette waterpumps are often called the "Corvette short" waterpump in the trade.

GM still services a new waterpump for your application under GM #12458924. However, it GM lists for $141.30. I don't think that this pump carries the original GM casting number, though. You can obtain a rebult unit from Delco or other aftermarket suppliers. The original CASTING number used for your car was GM #330813. A rebuilt waterpump, if it's made from a GM casting, will most likely have this number on it. There were only 2 CASTINGS that GM ever used for the "Corvette short" waterpump. These were GM #3991399 (1971-E1972) and GM #330813 (L72-82). Obviously, the latter casting is going to be the most common. If you purchase a rebuilt waterpump, make sure that you get the correct one for 71-82 Corvettes and NOT one for 1955-70 Corvettes. Check with the parts counter guy to make sure that he shows DIFFERENT rebuilders part numbers for the 55-70 Corvette and 71-82 Corvette. If he says that they are the same number, find another auto parts store.

The "Corvette short" waterpump uses a 3/4" pilot for the pump shaft. This is unusual for a Chevrolet application, most of which are 5/8" pilot. Only 1971-82 Corvettes, big block and small block, plus some HD truck applications use the 3/4" pilot waterpumps. It's important that the pump you get is correct for the car and has this 3/4" pilot if it's to work correctly with your water pump pullies. Actually, I don't understand how you got the new waterpump pullies that you have to work with the long-leg waterpump that you have. I know of no long leg waterpump that uses a 3/4" pilot and the pullies that you have should have a 3/4" pilot hole. You MUST NOT USE a waterpump with a 5/8" pilot in conjunction with a pulley with a 3/4" pilot hole UNLESS A PRECISION 5/8"-to-3/4" bushing is also used.

Also, the description of the balancer which you described sounds "suspiciously incorrect" for a 1979 L-48 application. Your engine should use a balancer which is ABOUT 6-1/8" OD and ABOUT 1" thick. If the balancer that you have is incorrect, that may present a problem later after you get the correct waterpump installed.

By the way, I want to make this point perfectly clear: although NO Corvette ever used a LONG LEG style waterpump, Corvettes are often seen with LONG LEG BLONDES in the passenger seat. In the "old days" I used to try to get as many of those into the passenger seat of my Corvette as possible. I specify no definition for the term "old days"; it COULD mean any day previous to today.

[Larry Clain]

Re:love that disclamer..!!!

Long legged ladies and Corvettes just seem to go together... I like blonds too...

[Joe L.]

Re:love that disclamer..!!!

Larry-----

I recall the 3 quintessential examples of the "breed" that occupied the right seat of my 1969 in days of yore; the others I've forgotten. Pat Jennings, Karen Robertson, and Dena Cooper were their names. Dena was from Missouri; Pat and Karen were born and raised right around here. Dena and Karen I should have forgotten by now. Pat was another matter, entirely. I wonder what she's doing today?