350ci Chevy Small block with 1-piece seal design
Stock crank
Stock rods w/ ARP bolts
Flat Top Hypereutectic Pistons

I plan to bolt this to a 700r4...may eventually bolt to a 5-speed.
This will end up a daily driver motor, abused at the track some...who knows what else since I constantly change my mind.


PROBLEM...
Machine Shop needs the harmonic balancer and the flywheel to balance. I told him I thought the flywheel would be neutral balanced...but he said on the new ones with 1-piece seal that there are weights on the flywheel. Also, if I change balancers later on, the balance would be close, but not as accurate.

I don't have the balancer or flexplate that came with the engine. I probably could scrounge up something. Machine Shop said he can use a used GM harm. balancer and a flywheel he has and I could bring him some on trade when I pick it up.

What do I do about the flywheel/flexplate issue? Can someone explain to me what exactly my problem is? What kind of balancing problems will I have in the future if I switch from a 700r4 to a manual transmission or vice versa?

What do I do about the balancer? Used stock? New one? How good of a balancer do I need? I don't expect this motor to put me into the 11s, but 12s are a possiblity.

Thanks for help.

 

Flexplate needed, yes. Damper, no.

I went to Checker and picked up one for '87-up, 153-tooth; something like $45. With the one-piece rear main seal, a counterweight that used to be outside the pan on 2-piece RMS cranks was moved to the flexplate/flywheel. So, you need such a flexplate/flywheel to balance the crank.

DON'T LET THEM BALANCE THE CRANK BY CHANGING THE FLEXPLATE BALANCE! The crank should be balanced by modifying the crank counterweights. Then, any one-piece RMS flexplate or flywheel will work.

 

They DO NOT need EITHER of those parts to balance your engine, any more than the factory needed them!!!! If they have them, and decide to take the "easy way out" by working on them instead of on the part that's actually out of balance to the rest of the world (the crank), then an off-the-shelf one of whatever they **** on will no longer work; you'll have a totally custom, unique, non-interchangeable assembly. So, of course, the very next thing that will happen to you, is that you'll need a new that piece whichever one it is that they get their d*** skinners on, and you'll have to take your crank, pistons, rods, and the other external, to get the one re-balanced. Very maintenance-hostile.

Any balancing shop that's in the business of balancing engines on a regular basis, will have a flywheel simulator to make up for the factory spec weight on teh flywheel. They don't need yours for that.

If they tell you they can't balance without them, thank them kindly, pick up your parts, and take them to someone else.

 

Don't be too hard on them. The shop that did mine typically only works on older 2-piece cranks (and they "crank" out quite a few performance engines each month). So, they didn't have a 1-piece "simulator", and asked if I would provide it. Which I did, with the stipulation that they would not modify the flexplate for the balancing, - which was consistent with their intent, anyway.

 

Talked to shop.

He said his balance machine is so precise, that need to use the flexplate and balancer I plan to run. He won't alter flexplate. I can change the flexplate and balancer in future, and it would be a small change...but noticeable on his machine. He said his machine is state of the art, same one used for WInston CUp engines.

I do know that all shops in the surrounding area send their stuff to his shop for balancing.


Edit: DeepSouth is the username I have from work...so, I'm same person

 

I would recommend NOT SENDING HIM THE FLEX PLATE.

Have him balance the crank CORRECTLY. Then maybe later, send him the flex pate, and have him balance that CORRECTLY. DO NOT allow the crank to be "custom balanced" to that flex plate, no matter what. Have the crank balnced to THE EXACT STOCK SPEC, NOT to the flex plate you now have.

 

Thats odd, since I have had over 20 motors balanced and blue printed and never heard that BS.

Time for another machine shop imo

 

It's too bad I'm about out of Machine Shops...
Time to Move, I reckon.

I'll talk to this guy on Monday...

 

Shop said the crank would not be "custom balanced" to the flexplate...that I won't have any problems changing the flexplate.

He doesn't have/wasn't familiar with a "simulator". I reckon he uses a stock flexplate to "simulate" with.

I'm going to have take his word, and let him balance it.
No one else in my area balances. Every machine shop (about 10 or so) send their stuff to his shop for balancing. Don't have the time to drive over 2 hours one way somewhere else. It's got to be better than no balancing at all.