1970 Harmonic Balancer Problem

[Lee McGlamery]

I have a very perplexing problem. I have a 1970 350/350. I just replaced my harmonic balancer with the proper high performance engine 8 inch diameter balancer. The old balancer was about the same diameter as the new one and the same thickness. Unfortunately, after comparing the new balancer to the old one, I discarded it because the outer ring had rotated on the inner part of the balancer. I know that I violated Rule 1 by trashing it. When I attempted to install the water pump pulley it hit the balancer. I checked part numbers and the car had the wrong water pump pulley so I replaced it with the proper pulley that was smaller in diameter and it fits. It is the correct part for the 350 horse motor. I checked the crankshaft pulley and the part number on it is correct for 350 horse engine. I checked the measurements on the water pump with a new one and the distances are the same. The big problem is that the double pulley on the crankshaft does not align with the water pump double pulley. The pulley on the water pump closest to the front of the car aligns with the crank pulley closest to the engine leaving the front crankshaft pulley without a matching pulley on the water pump. The car has power steering but I really do not think it is an issue. I know that the car has had the front clip replaced because of an accident. The car has the correct fan blade but wrong clutch if that matters. I am also replacing the fan clutch.

The car is a numbers matching car and the tach red line is 6000 which equates to the 350 horse engine. Does anyone have any ideas on what the problem may be? I even verified the dimensions of the new harmonic balancer with a Corvette parts vendor other than the one where it was purchased.

Thanks

Lee

[Joe L.]

Re: 1970 Harmonic Balancer Problem

Lee-----

If you are using the following parts, then you have the correct pieces:

1) harmonic balancer-----GM #12555879 (current SERVICE balancer for your app)

2) crank pulley----------GM #3858533

3) water pump pulley------GM #3848904 (original) or GM #3995641 (current)

If the above-referenced parts are what you have and if they don't line up, then one of the following 2 things are wrong:

1) you don't have the harmonic balancer FULLY pressed on;

2) your water pump and/or water pump hub spacing is incorrect. For your application, the distance from the block mating surface to the front of the hub face should be 5-9/16"

[Dave Suesz]

Too bad- ring problem is easy to fix *NM*

[Lee McGlamery]

Re: 1970 Harmonic Balancer Problem

Hi and thanks to Joe for his help. I found the problem. The harmonic balancer was about 3/4" from the crankshaft gear. I borrowed a balancer press and got it where it belongs. I also found out that the car has the wrong water pump on it. I learned that from a friend and also the correct water pump pulley was hitting the water pump casting. Long story short - it looks like everything is going to work once I get the correct water pump.

Thanks

Lee