Harmonic balancer - timing mark
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From: Snake handler
Harmonic balancer - timing mark
I just picked up a new balancer - I noticed that the timing mark on the old balancer was in a different spot (in relation to the keyway) than the new one - but I'm pretty sure the outer ring had moved on the old one.
I bought the correct balancer for my motor (1970 LT1) from Zip - is it safe to assume that the timing mark on the new balancer is in the right place or do I need to get a piston stop and confirm TDC?
I would think that's a pretty critical issue for a new/replacement balancer.
Hoping to re-install the freshly rebuilt motor this weekend. All new roller valve train!
I bought the correct balancer for my motor (1970 LT1) from Zip - is it safe to assume that the timing mark on the new balancer is in the right place or do I need to get a piston stop and confirm TDC?
I would think that's a pretty critical issue for a new/replacement balancer.
Hoping to re-install the freshly rebuilt motor this weekend. All new roller valve train!
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I would not take any chances, and would use a TDC finder tool to confirm TDC. It's to important to leave to chance. Since the motor is out of the car, it should be even easier to do.
Larry
Larry
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As posted previously by JohnZ:
The timing index line on the balancer (and the corresponding "0" mark on the welded timing tab) were moved 8 degrees counter-clockwise on long-water pump passenger car applications starting in 1969 (Corvette didn't change until several years later); if you have a "finned" balancer, it's previous to that change, and should have the index line directly aligned radially with the key slot in the hub, and the correct corresponding timing cover has the timing tab welded on. All the bolt-on timing tabs I'm familiar with are for post-1969 applications.
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The timing index line on the balancer (and the corresponding "0" mark on the welded timing tab) were moved 8 degrees counter-clockwise on long-water pump passenger car applications starting in 1969 (Corvette didn't change until several years later); if you have a "finned" balancer, it's previous to that change, and should have the index line directly aligned radially with the key slot in the hub, and the correct corresponding timing cover has the timing tab welded on. All the bolt-on timing tabs I'm familiar with are for post-1969 applications.
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If you find this to be true...PLEASE...snap a pic. I have worked on some crusty 55 year old motors where the rubber in the balancer is cracked and bulging out, and am always amazed that TDC is where it should be. In the meantime, I have put together this montage for your viewing pleasure.
Last edited by buns; Oct 9, 2008 at 09:39 PM. Reason: Edited photo.
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As posted previously by JohnZ:
The timing index line on the balancer (and the corresponding "0" mark on the welded timing tab) were moved 8 degrees counter-clockwise on long-water pump passenger car applications starting in 1969 (Corvette didn't change until several years later); if you have a "finned" balancer, it's previous to that change, and should have the index line directly aligned radially with the key slot in the hub, and the correct corresponding timing cover has the timing tab welded on. All the bolt-on timing tabs I'm familiar with are for post-1969 applications.
JohnZ is offline Report Post
The timing index line on the balancer (and the corresponding "0" mark on the welded timing tab) were moved 8 degrees counter-clockwise on long-water pump passenger car applications starting in 1969 (Corvette didn't change until several years later); if you have a "finned" balancer, it's previous to that change, and should have the index line directly aligned radially with the key slot in the hub, and the correct corresponding timing cover has the timing tab welded on. All the bolt-on timing tabs I'm familiar with are for post-1969 applications.
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The timing mark changed (except Vettes) from 1968 to 1969 on MOST Chevy products. I don't know what year the Vette balancers changed (about 71-72?), But you DO NEED to have the correct corrosponding balancer/timing cover tab matched to each other.
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From: Snake handler
Hmmmmm... my balancer is finned. But the application is 1970 - I'll call Zip to confirm the correct balancer.
I'll take some pics later today and post. I agree - checking TDC is a good idea.
I'll take some pics later today and post. I agree - checking TDC is a good idea.
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From: St. Joseph Mo
Tom:
Do small block dampers have witness marks? I don't have a small block damper handy but my spare bb has a diamond shape dimple on the hub and a round dimple on the outer ring.
Marks are about 165-170 deg from the tdc mark on the face.
Do small block dampers have witness marks? I don't have a small block damper handy but my spare bb has a diamond shape dimple on the hub and a round dimple on the outer ring.
Marks are about 165-170 deg from the tdc mark on the face.
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However, would not be a bad idea to add a couple of alignment punch marks when new (for checking down the road).
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So I have a finned balancer and it seems to be off just a couple degrees from the key way, when putting a straight edge to it.
The rubber and all appears to be good.
So how does one go about correcting? (If possible at all)
Thanks,
RK
The rubber and all appears to be good.
So how does one go about correcting? (If possible at all)
Thanks,
RK
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From: St. Joseph Mo
B: You cannot.
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Even if a balancer ring is suspect, it wouldn't hurt to punch the ring/hub so that after several miles it could be checked to see if the ring has moved---------------ESPECIALLY WITH AN ENGINE THAT WILL RECEIVE SOME PUNISHMENT!
