Flyweel Question

[cjm]

I have a 72-340 that has a cast crank installed in my 70 Cuda. Is there a way to check to see if the flywheel is externally balanced while it is in the vehicle? I have the inspection cover of the bell housing off, so a portion of the flywheel is visible. I have read that externally balanced mopar flywheels have 3 holes partially drilled (in a row).. I have also read that you can convert a neutrally balanced to a externally balanced by machining the flywheel with 3 holes...... I just want to know what is in there.............          Slight vibration, but not too bad..

[Chryco Psycho]

You are right on , you should be able to see holes on the front face of the flywheel

[cjm]

Thanks, I'll check it tonight....   I'm assuming that  Ma' Mopar drilled the holes as well, correct?? (IF it's externally balanced)...  (to make a nuetral balanced flywheel an externally balanced flywheel)....

[Chryco Psycho]

If the flywheel is properly balanced from t he factory or later on it has to have the holes 

[cjm]

Chryco, I didn't see any holes but there was a notch. I have attached a picture of a similar one that I found on the internet. What do you think?

[Jesus H Chrysler]

I don't know specifics about the flywheel, but I do know that externally balanced 340's had a different harmonic balancer that said "Use with cast crank 340 only"  That's one way to know if it's external balance without dropping the pan.

[Chryco Psycho]

Definatly a balanced flywheel but probably for a different application , there are numerous external offset balance engines , 340 , 360 , 383 cast crank , 400 & 440 6 pack with HD con rods & they use different offset weight so if you have a vibration & the book lists a 3 hole application your flywheel is from a different combo . The best way to solve this is have the engine balanced before assy adding metal internally to achieve a neutral external balance or at least exactly dialing in the balance of all rotating parts so you have not vibration but I am sure you do not want to tear down the engine to do this !

[cjm]

I don't know specifics about the flywheel, but I do know that externally balanced 340's had a different harmonic balancer that said "Use with cast crank 340 only"  That's one way to know if it's external balance without dropping the pan.

The crank (cast - stock )& balancer are correct for the engine. It came from a car that had an automatic trans, so the flywheel was added...  This was done a long time ago...  It's just the flywheel that I am not certain about. I guess I could just order a new one for that year and swap it out..