Cameron2

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.....

C409

..... Can you get a photo ? I'm confused by your comment that you have never seen a balancer behind the pulley AND dampener ... perhaps the outer ring has separated from the hub ? .....

s carter

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.

Cameron2

Good Morning, I did not test with timing light. I have water pump pulley off and belt idle. Noise is definitely from the Crank area. Sent some photos along.The center piece Marked ( GM ) is what I have never seen. Some Fellas have suggested I am looking at a 400 C.I. Block ? I do see what looks like some cracks but ? ? I suppose only way I'm going to know is pull it off ( looks like fun on U Tube ) Your input is greatly appreciated and curios to hear what you think going forward.This Vette definitely comes with a learning curve. Cameron
Thanks again,

WVZR-1

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.

Cameron2

The extra space from the Block makes sence. Belt would not line up otherwise. I am all for your wager my Friend. I've been at this a year and ready for some Road Time , not a Re-Build. ! Thank You for your insight and input. And, Thanks Corvette Forum
Cameron

WVZR-1

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.

Cameron2

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

Cameron2

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

WVZR-1

I might have thought you could have discovered that before the effort BUT now it's on to maybe "bigger and better things".

Cameron2

I agree. I had a bad feeling it was internal from the start but, no such luck. The engine had 150K plus on it and I was really surprised at the torque it still had. so, now I have new Alt, Water Pump,Rebuilt TPI,Dual Radiators and fans ect. to Bolt on to my next Engine... Your correct, moving on to bigger and better things.
C2