[Kenth]

Originally Posted by mgarblik

Thank you for clearing that up. My information came from an old GM film that showed the build process of Pontiac engines at the plant. I was almost sure I was watching the final dynamic balance being performed on rotating engines and just small amounts of finish balance material being removed externally. I remember thinking that was really bizarre as that would sort of marry the flywheel to the crankshaft which would be wrong. How in the world did they drill cast iron counterweights on an assembled engine without leaving metal in the engine? Amazing!

This may be the film?
9.45 into it they describe the balancing of the assembled block.

https://www.youtube.com/watch?v=9LuXf6gJ-jg

[mgarblik]

Originally Posted by Kenth

This may be the film?
9.45 into it they describe the balancing of the assembled block.

https://www.youtube.com/watch?v=9LuXf6gJ-jg

I am not sure if that's the same film. Some of it looks familiar because I remember being surprised by the number of women working the engine line. This film clearly shows and the narration states the balance involves removing metal from counterweights and all engines get this treatment. It also shows cranks being installed with major balancing completed before installation as the large balancing holes can be seen before the crank is lowered in he block. For some reason, I think the film deep in my memory was about 30 minutes long, not 10. This may have been an edited version. Also, my foggy memory seemed to to remember some manual transmission engines getting the final balance with the flywheels in place. This film showed all auto trans ones in that section. In any event, your explanation makes much more sense and would allow for much greater interchange without problems later in the engines life. Thanks for finding that.

[scott70]

Well this thread has helped me out on somewhat understanding and to ask questions. I just happen to had a new steel billet flywheel and clutch at the machine shop to check for balancing per McLeod own recommendations. Just went to pick them up and asked if he had balanced my motor ( 5 years ago) with the oem flywheel. He tried to look it up quickly but didn’t find anything. He asked if I still had the oem flywheel I said yes it’s still in the car. He said bring it in and they will check it and match it to the new flywheel if need be. So I guess I’m yanking the muncie out a little earlier than I had planned. The new McLeod flywheel was very close itself to neutral balance and by clocking the PP on it got the whole thing balanced but that might be all out the window now.