ztrips

Got a call from my machine shop. They are in the process of balancing my new 383 setup. Says it's 280grams out in back and 50 in front. This is with a Callies Dragonslayer 3.75" crank, manley h-beam rods, wiseco forged blower pistons. They say it would be best to balance externally since we are talking $500-$600 in metal for internal balance. I didn't think it would be that far out.. I am running a Fidenza Aluminum flywheel. Will this cause issues with balancing??

Why are engine builds never easy....

mos90

internal balance is always best.. most engine kits ive seen even if they say they are internal balance from the manufacturer need to be rebalanced..

if you get it done now and pay the price you will be happier. then you dont have to worry about vibration because you flywheel is not balanced properly. all you need is a neutral harmonic balancer and flywheel.

by the way your crank is 3.75" stroke..

MarkBychowski

The Fidanza by itself won't cause any issues if externally balancing. It comes with a weight bolted on that can be trimmed or welded to adjust the balance.

That being said, I would agree with mos90 about keeping it internally balanced. It's worth the extra cost in my opinion.

Either way you go, make sure you get your harmonic damper and flywheel balance checked to match.

CFI-EFI

Typically, 383 kits come internally balanced or externally balanced. It doesn't sound like you bought a "kit" but pieced together what you wanted. The older externally balanced 383 kits were set up to take stock 400 flywheels and dampers, because that was the origin of the cranks. With the introduction of the one piece rear main seal, in 1986, 350s were no longer internally balanced in the rear. The imbalance was much less than the 400, but still, it took an unbalanced flywheel to balance the engine. Unless you want to spend the bucks for the internal balance (preferred) you are going to have to used unbalanced components. A 400 flywheel isn't an option, because they never came with the 1 piece seal, crank, bolt pattern. The 400 damper is 8" in diameter and will hit your front cross member. What is the machine shop offering in the way of alternatives? Unless you want to get into modifying the front cross member, don't let them sell you an 8", 400, damper. And you'd best be sure that the crank has a key way in the front. If they externally balance it, make sure they provide the amount of weight and location so you can have them duplicated when replacement time comes.

RACE ON!!!

ztrips

They say the fidenza can be balanced by moving/changing the weight on the back of it. I have an ATI damper (neutral balanced) as well. From what I've heard the LT1s were actually neutral balanced in front and external in the rear, so this would be doing the same thing.

CFI-EFI

What you hear, is correct. But the situation is now different with the non-internally balanced 383 crank you are adding. I am sure they can properly imbalance the flywheel, but the damper is going to have to be similarly imbalanced. If they can work with your present damper, great. I am quite sure the LTx engines don't have the damper keyed to the crank. You will want it keyed. Don't forget to have them give you all the balancing specs when it is done.

RACE ON!!!

ztrips

The new damper is keyed as is the crank. The non-keyed crank is what started the whole engine rebuild..

CFI-EFI

RACE ON!!!

Bruce

my 383LT1 stroker, It rotating assembly not order in as a kit either. Forged eagle crank, H beam rod, JE piston. The crank I bought are for internal balance. I sent all my stuffs to AGOSTINO RACING ENGINE IN CANADA. I don't know what the cost to balanced but all I know I paid Total bill was $3100 that include re-work my heads to their stage II.

Bruce

Bruce

I think the metal cost $400-500 is about right. Do internal balanced motor. Doing this will allow you to use any brand clutch and flywheel with out vibrations or problem.


Bruce