replacing harmonic balancer
Thread Starter
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Joined: Apr 2018
Posts: 181
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From: Orlando, FL
replacing harmonic balancer
1970 454 garage car that Im working on but run the engine every few weeks to keep the engine fresh.
I was getting a constant screeching with my belts and eventually the WP belt broke. Screeching continued with the PS belt so I just removed it to get rid of the annoyingness of it. Notice a distinct vibration at around 2-3k rpm and can see a slight wobble of the crank pulley.
Can a spun bearing cause a wobble like this of the pulley?
Can a bad harmonic balancer cause bearing damage?
Can pulling and replacing the balancer be done with the engine in the car and the radiator/shroud in place?
Its a stock balancer. Any recommendations for a better replacement?
I haven't measured it yet, is it a 7" or 8"?
Thanks
I was getting a constant screeching with my belts and eventually the WP belt broke. Screeching continued with the PS belt so I just removed it to get rid of the annoyingness of it. Notice a distinct vibration at around 2-3k rpm and can see a slight wobble of the crank pulley.
Can a spun bearing cause a wobble like this of the pulley?
Can a bad harmonic balancer cause bearing damage?
Can pulling and replacing the balancer be done with the engine in the car and the radiator/shroud in place?
Its a stock balancer. Any recommendations for a better replacement?
I haven't measured it yet, is it a 7" or 8"?
Thanks
Last edited by Sidneyhop454; Dec 10, 2022 at 05:49 PM.
Safety Car
Joined: Mar 2009
Posts: 4,191
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From: Corpus Christi, TX
Spun rod bearing won't cause crank pulley wobble
the crank rotates in the main bearings, which will keep it straight. You balancer could have failed at the rubber ring between the hub and the inertia ring. That would account for wobble and vibration.
Taking the ting off w the radiator and shroud in place will be tough. There's not a lot of room for the puller if the shroud is in place.
Stock balancer is good. IIRC, it's an 8 inch.
the crank rotates in the main bearings, which will keep it straight. You balancer could have failed at the rubber ring between the hub and the inertia ring. That would account for wobble and vibration.
Taking the ting off w the radiator and shroud in place will be tough. There's not a lot of room for the puller if the shroud is in place.
Stock balancer is good. IIRC, it's an 8 inch.
Thread Starter
Instructor
Joined: Apr 2018
Posts: 181
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From: Orlando, FL
OEM balancer is internally balanced right? Will an aftermarket externally balanced one throw it off? Would it be recommended to remove the weight to bring it to '0'?
Im looking at this one as a replacement.
Im looking at this one as a replacement.
ATI 917740 Super Damper Harmonic Balancer
Safety Car
Joined: Mar 2009
Posts: 4,191
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From: Corpus Christi, TX
There are OEM balancers for 396/402/427 and they are all indeed for internal balance engines. There is a 454-specific unit that is externally balanced. That's the one you need. Check the mfrs data to be sure you get the right one if you're going aftermarket.
The ATI damper you're looking at seems to be the right one for a 454.
The ATI damper you're looking at seems to be the right one for a 454.
Tech Contributor
Joined: Aug 1999
Posts: 14,356
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From: At my Bar drinking and wrenching in Lafayette Colorado
Just because the pulley is wobbling doesn't mean there is any problem with the balancer. Bent pulleys are common. Remove the pulley from the balancer and then turn the engine over while watching the actual balancer. I'll bet it's fine. The pulley is bolted to the inner part of the balancer, which will not wobble when the balancer outer ring fails. Don't assume a problem where none exists. The balancer is not causing your wobble problem.
For info on what a slipped balancer looks like, and the replacement process (photos are for a small block, but BB process is the same), see my post here:
https://www.corvetteforum.com/forums...blem-post.html
Post #36 shows re-assembly.
Lars
For info on what a slipped balancer looks like, and the replacement process (photos are for a small block, but BB process is the same), see my post here:
https://www.corvetteforum.com/forums...blem-post.html
Post #36 shows re-assembly.
Lars
Last edited by lars; Dec 11, 2022 at 11:25 AM.
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is the pulley loose and it causing the wobble and belts screaching...check that first...if the harmonic balancer bolt fell out, or snapped and the balancer is walking off then it could be and issue....if you are playing in the front of a big block and you want to remain sane.....you should mark the hinges location on your hood, pull the hood, disconnect the radiator support upper bolts and loosen the lowers, disconnect the upper hose and tilt the support forward away from your motor...
Thread Starter
Instructor
Joined: Apr 2018
Posts: 181
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From: Orlando, FL
Just because the pulley is wobbling doesn't mean there is any problem with the balancer. Bent pulleys are common. Remove the pulley from the balancer and then turn the engine over while watching the actual balancer. I'll bet it's fine. The pulley is bolted to the inner part of the balancer, which will not wobble when the balancer outer ring fails. Don't assume a problem where none exists. The balancer is not causing your wobble problem.
For info on what a slipped balancer looks like, and the replacement process (photos are for a small block, but BB process is the same), see my post here:
https://www.corvetteforum.com/forums...blem-post.html
Post #36 shows re-assembly.
Lars
For info on what a slipped balancer looks like, and the replacement process (photos are for a small block, but BB process is the same), see my post here:
https://www.corvetteforum.com/forums...blem-post.html
Post #36 shows re-assembly.
Lars
There's a noticeable vibration that's new with the engine that seems to coincide with the wobble. Could this be a crank issue?
https://drive.google.com/file/d/1Ot-...w?usp=drivesdk
Thread Starter
Instructor
Joined: Apr 2018
Posts: 181
Likes: 6
From: Orlando, FL
is the pulley loose and it causing the wobble and belts screaching...check that first...if the harmonic balancer bolt fell out, or snapped and the balancer is walking off then it could be and issue....if you are playing in the front of a big block and you want to remain sane.....you should mark the hinges location on your hood, pull the hood, disconnect the radiator support upper bolts and loosen the lowers, disconnect the upper hose and tilt the support forward away from your motor...
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Tech Contributor
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From: At my Bar drinking and wrenching in Lafayette Colorado
I haven't pulled the pulley yet and will but here's a quick video of the damper and pulley currently.
There's a noticeable vibration that's new with the engine that seems to coincide with the wobble. Could this be a crank issue?
https://drive.google.com/file/d/1Ot-...w?usp=drivesdk
There's a noticeable vibration that's new with the engine that seems to coincide with the wobble. Could this be a crank issue?
https://drive.google.com/file/d/1Ot-...w?usp=drivesdk
Le Mans Master
Joined: Jun 2006
Posts: 6,393
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From: Tampa Florida
I don't see any wobble either but the sound is weird, like a scrapping sound that I wouldn't expect to hear. Maybe the timing chain rubbing against the timing chain cover? Do you know if the timing chain set is original?
Are your pulleys lined up straight when belts installed?
Are your pulleys lined up straight when belts installed?
Last edited by 71 Green 454; Dec 11, 2022 at 12:58 PM.
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From: Orlando, FL
https://drive.google.com/file/d/1P2z...usp=share_link
Also a closeup of the damper
https://drive.google.com/file/d/1PG2...usp=share_link
Thread Starter
Instructor
Joined: Apr 2018
Posts: 181
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From: Orlando, FL
I don't see any wobble either but the sound is weird, like a scrapping sound that I wouldn't expect to hear. Maybe the timing chain rubbing against the timing chain cover? Do you know if the timing chain set is original?
Are your pulleys lined up straight when belts installed?
Are your pulleys lined up straight when belts installed?
Could a bearing going bad cause this?
Tech Contributor
Joined: Aug 1999
Posts: 14,356
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From: At my Bar drinking and wrenching in Lafayette Colorado
Heres another shot without the pulley. I tried to limit the wobble as much as possible.
https://drive.google.com/file/d/1P2z...usp=share_link
Also a closeup of the damper
https://drive.google.com/file/d/1PG2...usp=share_link
https://drive.google.com/file/d/1P2z...usp=share_link
Also a closeup of the damper
https://drive.google.com/file/d/1PG2...usp=share_link
Highly unlikely. Bad bearings will cause a noticeable and audible "knocking" sound.
Thread Starter
Instructor
Joined: Apr 2018
Posts: 181
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From: Orlando, FL