Gents,
I noticed a chirping sound from my engine bay the other day. After a little snooping, I decided it was coming from the A/C belt, so I replaced the belt and it solved the problem. BUT... while doing all this, I noticed my crank pulley doesn't look perfectly true. The wobble is very small, but it's easy to see.

Does this demand my immediate attention since it's not the cause of the squeak? I've read up on changing the pulley, and it's well within my abilities, but I don't want to waste my time and $$$ only to find out that it's normal and have the new one wobble too.

Thanks!

fyi: it's a 99 FRC with about 90k miles and major mods are still a ways off, so I'm not interested in an aftermarket pulley or crank pinning yet

 

I've looked a several LS6 motors and believe a slight wobble is okay.

If you decide to change it, beware. I lost a motor doing this. We followed the proper shop manual procedure. While I don't have the shop manual with me, so I'm shooting from memory here. After putting on the new pulley (probably have to use a pulley puller kit), the procedure is something like first using the old bolt and torquing to around 240 ft-lbs, then taking the old bolt out and putting the new bolt in and torquing to something like 37 ft-lbs and then torquing an additional amount of degrees (140 maybe?).

We did this and the bolt came out about 2 laps into my first practice session and the harmonic balancer came off and bounced off the front subframe bending the crank and destroying the motor.

I believe that the process of pulling off the old harmonic balancer and pressing it back on loosened it so the press fit wasn't tight enough anymore. I talked to several racers after this incident and found this was fairly common and the more savy experienced racers use red locktite on the bolt (which isn't called for by the shop manual). Several forum members here have keyed the pulley.

You may be okay with a new pulley as the press fit will be tighter than in my case as we reused the old balancer (pulled it off to replace the rings for a rebuild). But, I would consider slapping some locktite on the bolt.

 

Thanks! I figure it's probably been this way a while, and I just didn't notice till now.
If it gets to the point where I decide to replace it, I'll definitley use the red loctite. Sounds like good advice.

 

Mine developed a bad wobble, causing the belt to chirp. I had the dealer replace it and it's been fine ever since. It does still have a slight wobble, and so did the other vettes on the dealership's used lot. I think it's normal.

 

Subdriver,

Have you ever pulled one that is pinned? Knowing the pinning process, I am wondering how one would line up the two drilled holes if you have to remove a pinned pulley again.

 

I'm not allowed allowed to pin mine per SCCA T1 rules, so I have no experience with that. Since the pin is between the crank and the pulley, I imagine it wouldn't be that hard to get it lined up since the pulley is just press fit onto the crank. Since mine was able to walk off on its own, it doesn't appear that hard to rotate it...