Harmonic Balance Measurement
Thread Starter
Burning Brakes
Joined: Jan 2006
Posts: 1,073
Likes: 331
From: Clear Lake Shores Texas
2016 C3 of Year Finalist
Harmonic Balance Measurement
I need to replace the harmonic balancer on my 69 350/350 as the outer ring has completely separated from the balancer. The failed balancer is not the original one, and it appears that GM has discontinued the production of the right one. I know it is 8" in diameter, but I need to know the width of the ring on an original balancer. The ones I have found so far seem to be too thin.
Thanks in advance for the help.
Thanks in advance for the help.
Drifting
Joined: Apr 2008
Posts: 1,305
Likes: 2
From: Lewisburg WV
thegazman
I have a 79, L-82 with an 8" balancer. I checked with my local Chevy dealer and the parts guy tells me the balancer for my engine is available from GM. It may not fit your 350, but worth a check.
Thread Starter
Burning Brakes
Joined: Jan 2006
Posts: 1,073
Likes: 331
From: Clear Lake Shores Texas
2016 C3 of Year Finalist
Thegazman - Is there any way you could measure the width of the ring of your balancer? I know it is tight fit. Mine is wider than 1 5/8"
Thanks.
Thanks.
Drifting
Joined: Apr 2008
Posts: 1,305
Likes: 2
From: Lewisburg WV
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Team Owner
Joined: Mar 2002
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This concerns me as I was about to begin a full engine refresh on my 76 L82. I just measured my balancer, and sure enough it's 1 and 5/8ths roughly. The one I was going to order from Summit states it's 1 and 1/4. Can I make this one work? Can the pulley be shimmed out from the balancer hub? Or do you just not pull the balancer as far down? 
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
FWIW, the harmonic balancer on my 350/300 engine is 1¼" thick. The LT1 balancer on the engine in the car is 1½". The front surface, where the pulleys mount is in the same relative place. The rear of the balancer ring on the LT1 balancer is closer to the timing cover than is the one on the 350/300. Switching balacers should be no problem.
As I understand it, a thicker/heavier balancer ring is better able to quell higher amplitude harmonic vibration and do it at higher engine rpm. Of course the trade off is a heavier rotating assembly.
Pete
Edit: I forgot to mention, both balancers are 8" diameter.
As I understand it, a thicker/heavier balancer ring is better able to quell higher amplitude harmonic vibration and do it at higher engine rpm. Of course the trade off is a heavier rotating assembly.
Pete
Edit: I forgot to mention, both balancers are 8" diameter.
Last edited by PeteZO6; Oct 7, 2010 at 09:47 PM.
Thread Starter
Burning Brakes
Joined: Jan 2006
Posts: 1,073
Likes: 331
From: Clear Lake Shores Texas
2016 C3 of Year Finalist
FWIW, the harmonic balancer on my 350/300 engine is 1¼" thick. The LT1 balancer on the engine in the car is 1½". The front surface, where the pulleys mount is in the same relative place. The rear of the balancer ring on the LT1 balancer is closer to the timing cover than is the one on the 350/300. Switching balacers should be no problem.
As I understand it, a thicker/heavier balancer ring is better able to quell higher amplitude harmonic vibration and do it at higher engine rpm. Of course the trade off is a heavier rotating assembly.
Pete
Edit: I forgot to mention, both balancers are 8" diameter.
As I understand it, a thicker/heavier balancer ring is better able to quell higher amplitude harmonic vibration and do it at higher engine rpm. Of course the trade off is a heavier rotating assembly.
Pete
Edit: I forgot to mention, both balancers are 8" diameter.
The balancer I got from my local parts house, which supposedly was the right one, was 1 5/16", like several others have mentioned. That one would work, as the overall width front to rear is the same as mine. As someone else mentioned, though, the one I have is much closer to the timing cover.
I have ordered a Pioneer balancer that is supposed to be the same as the one I took off. We will see. This is why I did not want to order one from one of the Corvette parts suppliers. There seems to be a lot of confusion over this and did not want to have to return one.
Thanks to all that replied.
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
FWIW, the harmonic balancer on my 350/300 engine is 1¼" thick. The LT1 balancer on the engine in the car is 1½". The front surface, where the pulleys mount is in the same relative place. The rear of the balancer ring on the LT1 balancer is closer to the timing cover than is the one on the 350/300. Switching balacers should be no problem.
As I understand it, a thicker/heavier balancer ring is better able to quell higher amplitude harmonic vibration and do it at higher engine rpm. Of course the trade off is a heavier rotating assembly.
Pete
Edit: I forgot to mention, both balancers are 8" diameter.
As I understand it, a thicker/heavier balancer ring is better able to quell higher amplitude harmonic vibration and do it at higher engine rpm. Of course the trade off is a heavier rotating assembly.
Pete
Edit: I forgot to mention, both balancers are 8" diameter.
Last edited by wcsinx; Oct 7, 2010 at 10:24 PM.
