C4 Dampener Noise
Thread Starter
Cruising
Joined: Dec 2015
Posts: 11
Likes: 0
From: Tucson Az
C4 Dampener Noise
My 86 developed a light knock from the front of Engine. I noticed it at idle but seems to go away around 1500 RPM. I could not isolate the noise so I let it go for a week.... It got nosier ,still at low RPM. I have isolated the noise to the Dampener..... I have rebuilt a few 350's ( Old School, First one a 62 /327 350 HP to a 60 over Thumper ) and have never seen a Ballancer behind the pulley and Dampener nor have I ever heard this knock from the Dampener area ..... Sure would appreciate some advice.....
Le Mans Master
Joined: Feb 2005
Posts: 6,485
Likes: 566
From: Clearwater Florida
My 86 developed a light knock from the front of Engine. I noticed it at idle but seems to go away around 1500 RPM. I could not isolate the noise so I let it go for a week.... It got nosier ,still at low RPM. I have isolated the noise to the Dampener..... I have rebuilt a few 350's ( Old School, First one a 62 /327 350 HP to a 60 over Thumper ) and have never seen a Ballancer behind the pulley and Dampener nor have I ever heard this knock from the Dampener area ..... Sure would appreciate some advice.....
Melting Slicks
Joined: May 2014
Posts: 2,895
Likes: 592
From: New Port Richey FL
does the noise go away with the drive belt off?
Make sure there is no problems with any of the Accessory's (Alternator, A/C Pulley/Bearing,Water Pump,Air Pump) All Brackets and bolts are tight, Including Dampener Bolts.
Hopefully it's something on the outside of the Motor.
Last edited by s carter; Jan 1, 2017 at 09:14 PM.
Thread Starter
Cruising
Joined: Dec 2015
Posts: 11
Likes: 0
From: Tucson Az
Harmonic Balancer.
The outer ring can separate for each other, I have seen the Balancer Ring wonder into the timing cover. if it is failed to the point of noisy one quick test though not conclusive is get a timing light and you are confident your timing is good give a look and see if your timing mark is close to see if the two halves have moved. Also you can take a paint pen and draw lines between hub & ring see if they move
does the noise go away with the drive belt off?
Make sure there is no problems with any of the Accessory's (Alternator, A/C Pulley/Bearing,Water Pump,Air Pump) All Brackets and bolts are tight, Including Dampener Bolts.
Hopefully it's something on the outside of the Motor.
does the noise go away with the drive belt off?
Make sure there is no problems with any of the Accessory's (Alternator, A/C Pulley/Bearing,Water Pump,Air Pump) All Brackets and bolts are tight, Including Dampener Bolts.
Hopefully it's something on the outside of the Motor.
Thanks again,
Team Owner
Joined: Sep 2003
Posts: 25,394
Likes: 2,741
What you've got in your image is actually the crank pulley. The complete part # I'd think is 14055116. The AMC is correct also for identification. The pulley has a considerable offset that you're not accustomed to seeing on the older SBC where the pulley was generally very flat with little or no offset.
Your 2d & 3d image seems to show where a bit of the "dampening" material has torn away from the hub of the balancer. I'd wager on a balance issue.
Your 2d & 3d image seems to show where a bit of the "dampening" material has torn away from the hub of the balancer. I'd wager on a balance issue.
Last edited by WVZR-1; Jan 7, 2017 at 11:11 AM.
Thread Starter
Cruising
Joined: Dec 2015
Posts: 11
Likes: 0
From: Tucson Az
What you've got in your image is actually the crank pulley. The complete part # I'd think is 14055116. The AMC is correct also for identification. The pulley has a considerable offset that you're not accustomed to seeing on the older SBC where the pulley was generally very flat with little or no offset.
Your 2d & 3d image seems to show where a bit of the "dampening" material has torn away from the hub of the balancer. I'd wager on a balance issue.
Your 2d & 3d image seems to show where a bit of the "dampening" material has torn away from the hub of the balancer. I'd wager on a balance issue.
Cameron
Team Owner
Joined: Sep 2003
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I might go about the repair/replacement a little differently than some/most. I might consider a rebuild of the balancer if it was known to be an original vs. replacing with the after-markets that are available. There are a couple responsible rebuilders that do this balancer and do it to last. I believe a friend still uses Dale Manufacturing for his. You're looking for a GM# 6272221 or an equivalent I'd think for an '86. Check and confirm before ordering I'd say to make sure it's correct.
Thread Starter
Cruising
Joined: Dec 2015
Posts: 11
Likes: 0
From: Tucson Az
86 Pulley
Good Morning, I have the Pulley off. I see no damage. Pic. shows a math. I located this Pulley in Texas It is no longer in production So, 2nd Pic. is the Harmonic still on Crank. I do see what looks like separation you referred to Will pull it this Morn. More later. Cameron
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Thread Starter
Cruising
Joined: Dec 2015
Posts: 11
Likes: 0
From: Tucson Az
Bad Harmonic Balancer and.....
Put the whole thing back together. New Balancer and all. Fired it up, same freeking noise. So, put it on a just rained on Street, made three semi sideways passes and the timing chain cut loose and now I have some very identifiable metallic knocking noises...... the engine was tired and I've put lots of new parts and tuned TPI. Now, on to a Fresh Mill. No Quit since I wrapped my *** in glass ! !
Thanks again to all who responded.
C2
Thanks again to all who responded.
C2
Team Owner
Joined: Sep 2003
Posts: 25,394
Likes: 2,741
Put the whole thing back together. New Balancer and all. Fired it up, same freeking noise. So, put it on a just rained on Street, made three semi sideways passes and the timing chain cut loose and now I have some very identifiable metallic knocking noises...... the engine was tired and I've put lots of new parts and tuned TPI. Now, on to a Fresh Mill. No Quit since I wrapped my *** in glass ! !
Thanks again to all who responded.
C2
Thanks again to all who responded.
C2
Thread Starter
Cruising
Joined: Dec 2015
Posts: 11
Likes: 0
From: Tucson Az
Dampner
C2