I built a 383/6 speed for my 87 Monte Carlo SS. I have a internally balanced eagle stroker kit. I noticed the harmonic balance was out of balance. So I used the search button, I recently found out the the stock flywheel is externaly balanced. I have 500 miles on the motor. I took the flywheel and pressure plate to be balanced. My machine shop is telling me I could have seriously screwed the motor up, he told me to check the bearings. The motor starts up fine i have a changed the oil 2 times (15 Minutes, and 400 Miles) and there has been no metal in the oil. Has anybody else had this issue and was there any bearing damage.

Thanks
Chris

 

you should just be able to knock off the counterweight on the flywheel

 

the right thing to do would be to take it to the machine shop and have it balanced correctly, but i dont believe that is what he is asking.

i dont think it would have caused any damage but it might not be a bad idea to check them anyway

 

- so the rotaing assembly was purchased internally balance - if you have the kit number, call Eagle - it may be balaned internally with the factory flywheel counterweight considered.
If it's an LT1 motor - the harmonic damper is zero balance from the factory - with a weighted flexplate or flywheel.

If it is a Gen 1 motor and the front uses a weighted balancer and the flywheel is weighted - those should have been replaced with nuetral/zero balanced parts at the initial build.

If your assembly was set for zero/nuetral balanced flywheel - I'm suprised you didn't have a very noticable vibration from day one.

If you have run the motor significantly out of balance for any period of time you have a good chance of premature bearing wear. Possible stress in rods and main cap areas.
Every motor is different - you'd have to tear it down and inspect.

 

You are right,i would have had the whole RA balanced not matter what eagle says it is..

 

The balance was checked before it shipped out from cnc motorsports. It is internally balanced. I am having the flywheel neutral balanced. I am just wondering if there can be any engine damage from running this flywheel on a internal balance motor.

 

As stated before - if all was balanced intended for a neutral flywheel - and you used the weighted one for 500 miles - it could have caused premature bearing wear or stress. If you didn't even notice a vibration, or a minimal one - I'd drive on and hope for the best versus tearing the whole motor down, or pulling the pan and some bearing caps. Chances are good with those few miles and no radical vibration, you saved it on time.

 

Took the pan off this morning and there was bearing damage. Glad I took the pan off.

 

smart man - glad you did too.
I'd have guessed not - but like I said, every motor is different
good luck

 

If you are running a manual, you need to have the flywheel nuetrally balanced. No exceptions! If an automatic is going to be used, all you need to do is remove the counterweight on the flexplate. I build and install these engines all the time and have never has a problem with Eagle rotating assemblies, as long as you follow simple rules.

 

can you post pics of the bearings? I ran with a vibration - curious to know what may be inside...

 

These are the standard Clevite P-Series Bearings
MS909P and CB663P

 

DAMN - I guess I'll be rebuilding this winter


glad you caught yours early

 

wow, and you really did not feel a vibration at all

 

I had some vibration. I did not really pay attention to it. I am glad I caught this early too about 475miles. There was a little shimmy on the harmonic balancer that had me worried so that why i went looking. The caps are rear main and the 4th cap inline. There was no damage to the crank luckily. The machine shop says whenever I install a new clutch to have the whole assy rebalanced again.