machine shop called and wants me to bring a flywheel and harmonic balancer so they can do a proper internal balance .

is it best to just buy a new stock flywheel and balancer?

im going to be using a spec stage 4 clutch, but i dont want to shell out for their flywheel.

 

Good luck. One piece rear main seal engines are externally balanced from the factory. If it's internally balanced, it should have a neutral balanced damper and flywheel. If that's the case, why does he need them? It makes more sense that he needs them to do an external balance. Is it possible you miss understood his balance method?

 

What slow poke said is correct.

Internal he doesnt need the balancer/flywheel to balance the engine. If its internal however, YOU need to get your flywheel zero balanced (or have him do it). Knocking the counterweight off it will be pretty close, but taking it to the machine shop is ideal.

External he needs them to balance the engine.

 

If you think about what you just said, He needs it to balance the internals or he needs it to zero balance it, kind of contradicts what Slopoke said. You're saying he needs it either way. Aren't you?

And oh BTW, internal balance is often EXPENSIVE since it usually entails adding weight. Not always but often.

 

Let's not get confused here. The question indicates a basic misunderstanding. An LT1 harmonic "balancer" (better called a damper") should already be neutral balanced. But if he wants to check it, kudos to the machinist. A stock LT1 flywheel will have a weight to "balance" an imbalanced stock rotating assy. IOW, the stock RA is externally balanced. There are two basic choices.

1. Use a stock, unmodified flywheel. In this case, the whole assembly will need to be balanced to that specific flywheel and the result will be considered externally balanced. The actual addition/removal of material could be done either externally or internally.

2. Use a neutral balance flywheel. In that case, the RA itself will need to be neutral balanced and the result will be considered internally (neutral) balanced.

A stock RA or equivalent requires a specified amount of external counterweight to balance the whole assy. That's why you can swap stock flywheels without doing any balancing, they all have the same counterweight. An aftermarket RA (like a stroker in this case) will usually NOT have the same specified amount of "imbalance" as a stock RA. So, you can't just bolt up a stock flywheel. One or the other must have weight added/removed. As long as you need to do any balancing at all, it makes sense to me to have it neutral balanced. IOW, there will need to be material added or removed from the crank.

Rich

 

Also a internal balanced setup will reduce the Angular Inertia of the motor because you take the big heavy balance weight off the flywheel which is farther away from the crank centerline. That's going to help with engine and vehicle acceleration. It's also going to help torsional flexing of the crank. Both are very good things for performance and longevity.

Bret

 

Its my understanding that LT1's are internaly balanced in the front and Externally in the rear, but dont hold me to it.

 

well it sounds like i prefer internal balancing, even if its more expensive.

so i can bring him a new/stock damper, and a new/stock flywheel that i will use, but make sure he neutral balances the flywheel first, then the RA.

 

Right!

Rich

 

Sorry that was written quickly.

You can internally balance the engine without the flywheel and dampre.
You cannot balance externally without the flywheel and dampre

If you go internal, you will need to have the flywheel nuetrally balanced, but this is seperate from the initial internal balance job so he shouldnt need them unless he is just double checking things.

Hope that cleared it up.

 

well just in case anyone else reads this for advice, advance auto parts carries a new (not reconditioned) replacement damper for $60. (the gm part is $150ish)

unfortunately, no parts places seem to carry a new flywheel, only reconditioned.
jason chromer quoted me $180 for the flywheel.