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Cam Button Issue?


DMolyneaux
10-05-2014, 03:02 PM
This is a 1987 Buick LeSabre Limited v6. I am transferring this query from another thread. Car was running fine but suddenly started making a "knocking" noise at low rpm/idle. No evident performance issues. It then died while driving down a road (after about 2 weeks). Now in a no start or missing as if jumped time. Timing chain and gears were replaced last Fall.
I DO remember having problems getting the cam button to sit in place when reassembling after doing the chain. What exactly does it do? Would it allow the chain to slack and hit the cover (knocking noise) or jump time again?
There could be other issues but this seems likely. There are no codes being shown except 12.

Blue Bowtie
10-05-2014, 04:11 PM
Another somewhat common problem is the interruptor ring(s) on the rear of the harmonic balancer becoming loose, and the balancer rubber/elastomer ring failing. With the accessory belt removed it's fairly easy to grab the outer ring (belt sheave) and determine how much movement is happening. There should be none detectable by hand, unless you are a close relative of Superman.

It's common enough that Dorman has a good supply of replacement dampers available through lots of sources. Mine let loose after 18 years and 206K on the odometer. Unfortunately, they are selling for about a Benji, but if it gets your engine running...

DMolyneaux
10-05-2014, 04:28 PM
THAT is really interesting. I noticed when I was looking in the area that there was some rubber protruding from around the ring. Glad I posted the question before going into the timing chain cover. Toad home today, I will look at the balancer tomorrow!

DMolyneaux
10-05-2014, 04:33 PM
Just thinking though, what about the "knocking" noise? That would not explain it would it?

Blue Bowtie
10-05-2014, 07:41 PM
When the rubber fails the steel shell of the balancer is allowed to ride on the cast hub of the balancer. As it turns and the torsional power pulses from the engine firing and the force of the belt pulling it from side to side it can cause a knocking or hammering sound.

DMolyneaux
10-06-2014, 07:53 AM
Thanks, looking at it later this AM.

DMolyneaux
10-06-2014, 10:40 AM
OK. So with some effort, I can rotate the outer ring on the rubber. Does not seem loose enough to cause the noise, but I assume that ANY movement could cause the interrupter to be out of place and cause a no start or other timing issue????
I will order a new balancer regardless as it is clear that this one is failing.

DMolyneaux
10-09-2014, 09:01 AM
:smile:Another somewhat common problem is the interruptor ring(s) on the rear of the harmonic balancer becoming loose, and the balancer rubber/elastomer ring failing. With the accessory belt removed it's fairly easy to grab the outer ring (belt sheave) and determine how much movement is happening. There should be none detectable by hand, unless you are a close relative of Superman.

It's common enough that Dorman has a good supply of replacement dampers available through lots of sources. Mine let loose after 18 years and 206K on the odometer. Unfortunately, they are selling for about a Benji, but if it gets your engine running...

:smile: This was it. Thanks for saving me from having to go deeper. Had to wait for shipping since none available locally and cost about $100.

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