I am replacing the harmonic balancer on my 99 corvette. All of the info I have read say to scribe the old balancer to the crankshaft and align the new balancer in the same orientation. Can't seem to find any specific instructions on how to line up on the new and old balancers to get the same orientation - there is no timing mark for top dead center that I can see like an older engine - I assume you have to line up the holes drilled in the rim of the balancer but want to be sure. There are holes drilled around the rim of the balancer at an even spacing and 6 holes that are all fairly close together in one spot on both the old and new balancer however the 6 holes on the new balancer I got are slightly closer together than they are on the original. I assume that I should line up the center line of the 6 close holes on both balancers to get the same orientation. Can anyone confirm if that is correct or let me know the correct way if not. By the way, if I do line up the 2 balancers using the 6 holes the 3 spokes in the center do not line up but not sure if that matters.

thanks
Gary

 

Are you using the service manual?

 

No I don't have the service manual but I found quite a few posts on various sites with instructions on how to replace the balancer including a GM technical service bulletin. They all say to mark the old balancer orientation to the crank and transfer the mark to the new balancer so it is lined up the same, however I didn't see a specific detail on what reference marks to use to line the old balancer up to the new.

Gary

 

If you do not have a service manual the next best thing would be an ALL DATA DIY account.

 

What is an all data diy account?

 

Blueacre, here's the deal:

Some, apparantly not too many, of the manual tranny earlier engines were externally balanced at the factory by installing lead weights in the drilled holes of the flywheel and sometimes also the balancer.
So, if you are one of the "lucky few" who has lead weights crammed into the balancer, you must try to replace and orientate these weights in the new balancer in the same position relative to the crankshaft. The weight will be a little round slug pressed into one of the holes around the balancer, either flush or slightly receded into the hole.

If you have no weights, then you can mount the new balancer in any orientation you wish, it's neutral-balanced. If you have an auto tranny, no worries, they weren't balanced this way, just slap that new one on.

So, before you remove the old balancer, mark it and the crank snout anywhere, so you could put the balancer back on in the same general orientation. Then pull it off, and look for any lead weights. If you find a little weight, pull it out. Then insert the weight, or a new weight, into any convenient hole in the new balancer. Then lay both balancers flat in front of you with the weighted hole facing at 12:00 o'clock.
Mark the new balancer in the same clocked position as the old balancer's mark. Then install the new balancer on the crank, matching the marks again.
It's much easier to do than to explain, hope you get the idea.

My experience has been that the balancer weight is pretty small, and causes minimal noticeable vibration if left out. However, for optimal smoothness it's worth a couple minutes to check it out, I think.

DG

 

Google it and see for yourself.

 

Gary, there's a lot people have learned over the years about these OEM style balancers. Don't trust any of the old threads that say "use parking brake, good'nough", etc. Make damn sure you hit the torque specs GM specifies when installing your new part. You need to isolate the crankshaft from the drivetrain using a flywheel lock or strap wrench. Otherwise that balancer could loosen and cause progressive ($$$) damage to your engine. Good luck.

 

i have a 99 and my serp. belt was thrown off and when i put new one on, i notice a wobble. Looked around here and it seems like alot of 99 have that problem .Is this why you are changing yours?

 

Don't hurt yourself:

http://lmgtfy.com/?q=all+data+diy