Loose balancer: This can't be good


Go on red!
May 7, 2002
So, I had a rattling noise, searched the threads in here and tracked it down to loose crank pulley after I loosened the belt. Now, I haven't pulled the crank bolt out yet to know how bad it really is...

So if all goes well I can slap on a used balancer for $50-70 and reuse the keyway that is in there.

If things go bad, then the crank could be out of round and cause this "new" balancer to crack like the first one. Bearings are also coming out too. At that point, I'm pulling the f'n engine so I don't have to work on the ground. I can have it out in a few hours. No biggie, plus I can reflash my awesome PTS converter while it is out...

Options, supposedly I can have the crank rewelded or something to make the balancer fit tight again.

I just can't seem to understand why would my balancer suddenly come loose like that. The crank bolt is tight. I mean tight. What if the crank was under duress and will not live much longer? I have billet main caps, align honed and all that. Should I drop the pan and look at the bearings? I have an extra oil pan gasket somewhere around here. I hate dropping the pan while the engine is in the car. I don't want to grenade the engine and trash my $1000 billet roller cam and hurt my expensive Wiesco pistons, if I can avoid it.

I had a couple of bouts recently with severe knock (got out of it immediately). Would that cause this balancer to come apart?

IMPORTANT: I also noticed the sound only after I installed my RJC power plate on Saturday. During the install I noticed some oil in my intake so I cleaned it out w/ carb cleaner. Some of it must have gotten into the combustion chambers because when it fired up, it popped really loudly and then shutoff. I'm guessing this was the cause. I drove for 40 miles since that event. Unfortunately, that doesn't help things. Since I couldn't hear the rattle from inside the car, I drove it Sat afternoon and Sunday, then noticed the noise from outside the car and then started investigating on Sunday night.

Any insight appreciated and thanks for reading my longwinded post,

Had a cracked harmoic balancer on my son's car. We caught it when doing a timing chain. I suspect that the bolt securing that balancer was overtighened with a powerful impact wrench before we ever got the car. If this is the case with yours, maybe only the balancer is damaged. I would pull the balancer to check the hub for damage.
I have almost 17,000 miles on this engine. The bottom end hasn't been apart since it was rebuilt in Christmas 2002. The bolt requires like 200-220 ft-lbs to tighten it :eek: Lots of 120+ mph passes though...
I had a similiar situation. The balancer had cracked and the key way hole was "wallowed" out. I got lucky and only needed a new keyway and balancer.

Good luck!
I hear the keyway is no fun to try n pull with the timing cover on. I have the precision high vol front cover too. The voice in my head is saying pull the engine out and tear it all the way down...I guess once a year is about right to take the engine out and pull the heads and clean it all up. I think the metal from the balancer had to go somewhere, namely in the oil pan which means the screen would have metal trapped in it too...dayum...
I cracked a balancer five years ago with crazy knock. Tried a Kenne Bell Chip. I think they had it set on auto-destruct. Did not know untill rebuild.
My brother-in-law had 2 different cars when the keyway broke :eek: ! Very wierd, as I've never seen another car do that.
If the keyway slot in the balancer is cracked, it's probably because the bolt wasn't tightened enough and came loose.
A standard 1/2 in. pneumatic impact wrench usually won't tighten it enough. I had to use a high performance (read: MADE IN USA) 1/2" impact to get it tightened to 200 lbs/ft. You need to put a vise grip on the flex plate to prevent the impact from turning the engine, lessening the torque on the bolt...it's gotta be TIGHT!
I had one wobble and damage the front snout of the crankshaft. Even with a new key and balancer, that engine still had a wobble, because the crank snout was damaged.

Just be sure you use an impact wrench that goes beyond 200 lbs. /ft.
A damaged crank snout can be plated and reground. I had one done last summer. Costs about $100.