C1 Harmonic Balancer Problem
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4th Gear
Joined: Feb 2021
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C1 Harmonic Balancer Problem
Hello Everyone,
I have a bone stock 1962 Corvette and suddenly the water pump/generator pully and the harmonic balancer pully began to make contact with each other. I assumed the water pump must have been bad, so I replaced it only to have the problem still exist when I started her up after installing a new water pump. My only other thought now is that maybe the harmonic balancer has come loose somehow? Or maybe it was damaged during a previous water pump installation (as the one I took off the car was not the original - it had a 1968 date code). Any advice would be GREATLY appreciated.
I have a bone stock 1962 Corvette and suddenly the water pump/generator pully and the harmonic balancer pully began to make contact with each other. I assumed the water pump must have been bad, so I replaced it only to have the problem still exist when I started her up after installing a new water pump. My only other thought now is that maybe the harmonic balancer has come loose somehow? Or maybe it was damaged during a previous water pump installation (as the one I took off the car was not the original - it had a 1968 date code). Any advice would be GREATLY appreciated.
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Welcome to the Forum, and congratulations on your C1! 
I would suggest asking this question in the C1/C2 sections at https://www.corvetteforum.com/forums...-1953-1967-21/.
Best wishes for a simple and inexpensive fix!
I would suggest asking this question in the C1/C2 sections at https://www.corvetteforum.com/forums...-1953-1967-21/.
Best wishes for a simple and inexpensive fix!
Burning Brakes
Joined: Nov 2001
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From: St. Petersburg FL
Those pulleys are pretty close (like about .040 in apart) under normal circumstances, but of course something has gone wrong for them to be making contact. Few ideas:
In addition to the suggestion above, check to see if the balancer is coming loose from the crank. I don't believe that the 250 and 300 hp '62s had a retaining bolt--rather, the balancer was only press fit on the crank. They can come loose. If your '68 balancer was from an application that did have a bolt, then maybe the press fit is not good enough for a no-bolt application.
It may also be possible that one of the pulleys is damaged.. Was the water pump pulley in good shape when you changed the pump? There is a reinforcement that is supposed to keep the pump pulley from cracking (from cyclic loading). Not sure how well the reinforcement actually works, but in any case the designers were concerned about that pulley failing over time.
You already changed the pump so that's probably not it, but I know from experience that a replacement (non-GM) pump body can be out of tolerance enough for the pulleys to hit each other.
In addition to the suggestion above, check to see if the balancer is coming loose from the crank. I don't believe that the 250 and 300 hp '62s had a retaining bolt--rather, the balancer was only press fit on the crank. They can come loose. If your '68 balancer was from an application that did have a bolt, then maybe the press fit is not good enough for a no-bolt application.
It may also be possible that one of the pulleys is damaged.. Was the water pump pulley in good shape when you changed the pump? There is a reinforcement that is supposed to keep the pump pulley from cracking (from cyclic loading). Not sure how well the reinforcement actually works, but in any case the designers were concerned about that pulley failing over time.
You already changed the pump so that's probably not it, but I know from experience that a replacement (non-GM) pump body can be out of tolerance enough for the pulleys to hit each other.
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