befu

iTrader: (2)

I am looking at a nice 350 short block, one piece rear main seal. Block completely machined and bored .030. New eagle rotating assembly that came balanced with a flex plate. The one piece 350's are rear external balanced, so this assembly was balanced with the flexplate. Since I want it for my boat, I need to put my flywheel on it which is balanced for a standard Chevy assembly. Changing this will throw the balance off, but I am not sure how much. The stock chevy stuff is production balanced anyways.

So my question is, can I pull the flex plate, figure out how out of balance it is by adding weights to statically balance the original flexplate. Then, balance my flywheel with this same weight attached thus replicating the flexplate balance.

Did I say that right?

Any thoughts?

ezstriper

if it's a std 350, flywheel should be neutral balance, you will need a std trans flywheel for a one piece rear main seal engine...I doubt that the flywheel was actually balanced when they did the engine...should be 168 teeth

befu

iTrader: (2)

Looked at the flywheel from my old two piece rear main and they are neutral. The older 350's were internal balance.

My flywheels for the one piece mains have a cast lug, so they are not neutral. The flex plates that come on the 90 engines are also weighted. The kit from eagle says it was balanced with the flexplate. You can get internal balance cranks for the one piece main 350's, but they are more expensive.

larose481

You need to find a machine shop that can weight match your flywheel. Muellers machine in Auburn, MI can do it. 989-662-7349 and ask for Rob. Tell him Chad sent you. Should be around $50 as i used to do all his balance work when I worked for him. Great guy.

ezstriper

you should still just be able to get a manual flywheel for a late model 350 and be good...

sprink58

Not to sound obvious but have you spoken to the builder?

Mr Maine

The old style 2 piece 350 is a neutral balanced flywheel while the new style 1 piece has a weighted flywheel.

So you are saying that the flex plate on it right now is neutral balanced? If so just take your single piece rear main flywheel to a machine shop and have it neutral balanced to match.

befu

iTrader: (2)

Arghh, this is where it sucks being an engineer and I have to try over explaining things to the point that I make them confusing! OK, here goes.

Looking to buy a 1 piece rear main short block that was balanced with a weighted flex plate. I will have to use a solid flywheel obviously, that is not neutral balanced.

Can I or the machine shop just balance the new flywheel the same as the old flexplate? I do not want to pay to have the whole motor tore down and rebalanced, defeats the purpose.

Sprink, it was obvious and no I never thought of calling the machine shop. main reason is we have a good shop local, but not cheap. to take my old block, clean it, Magnaflux, bore and hone with torque plates, line bore it and new cam bearings would run about $770 with taxes and "shop supplies". So I tend to look at doing things myself when you talk that kind of pricing. heck, summit sells a 355/383 block for $800 ready to go with all that done and clearanced for the 383 crank!

EZ, I believe my standard flywheels would be "close enough". but someone paid to have this motor properly balanced, so I was just looking at ways to preserve some of that work and not completely redo it or go back to factory balanced.

Basically Larose spelled it out. So they can weight match the two flywheels, that is what I really want done, just didn't know what it was called. It made sense to me mechanically, I was just wondering if there was a reason it wouldn't work. I think I have been wrong a couple of times before, can't remember.........

Brian

befu

iTrader: (2)

OK, I never talked to the machine shop, but I did send a note to Eagle who sells the balanced rotating assembly. Kind of blew it off as I was expecting some legally butt covering response. What I got was a direct answer that confirmed what I wanted to do and it is OK!

From Eagle:
Brian,
The amount of imbalance built into a flexplate and flywheel is actually the same. When we balance the assembly, all of the adjustments are done on the crank itself. We do not alter the flexplate at all. We do it this way specifically for this reason. You can change to an O.E.-spec flywheel that is unaltered and not affect the balance at all. Just bolt the flywheel on (make sure it's clocked correctly) and go! That's it!

Thanks for your business!
Alan
Eagle Specialty Products, Inc

So I am going to buy the motor and set it in the corner for when I repower. Now I will keep my eye open for another short block that has been done or just build one over time.

Thanks all.

Brian