well have fun finding a external dampner with belt grooves in it. scrap your idea or have it internal balenced those are your two options

 

Since the front is nuetral, when you build an internally balanced stroker, you just need to have the rotating assembly 0 balanced, along with the flywheel. With an external balance lt1, you still have the nuetral front, but you do all your balancing with the flywheel. (thats the stock way). Im still kinda confused as to what you are trying to do.

 

The whole balance thing confuses me between the definition of external and internal. It confuses alot of people...but either way all I need is a damper that will work with an LT1 that has the standard 383 counterweight on it. It's driving me nuts because I KNOW I've seen one before...maybe it's one of those parts no longer in production or something.

 

just have the rotating assy internally balanced .then use stock parts lt1 balancer and stock flywheel with the weight taken off(should be checked for neutral balance)

 

Why dont you just use the standard balancer and have it externally balanced at the flywheel?

 

if its a 26oz balance like a 400 SB, itll have to have a weighted flywheel/flexplate and harmonic balancer. but the only cranks that are like that are stock chevy 400 cranks i believe.

im thinking that if a cola crank isnt neutral balance, someone put weight in it. i cant imagine cola making a $800 crank with a 26oz imbalance like a POS factory 400 SB cast crank.

 

The back of the crank balances just like your LT1 does...all the flywheels and flexplates are interchangeable between late 350's and this crank. However the front is the same as a 400...8" counterweighted damper as opposed to your typical late 6 3/4 non-LT1 damper.

I suppose I could always refer to another machine shop about balancing, maybe one that does motors like these. Couldn't hurt!

The crank is a very nice piece, I just dont think it was made with balancing for LT1's in mind. They were intended to be used as a high-torque replacement for the Vortec 5.7 and TBI motors in mid-'90's trucks. Kinda makes you wonder why GM contracted cola to make 4340 cranks, then use PM rods and hyperutectic pistons (look like speedpro's with a GM part number). They must have alot of confidence in those rods, or not alot in the cast cranks!

I'll do some browsing for a speed shop around here and ask their opinion. After thinking about it, the 8" damper is probably 8" for a reason, and I doubt I'd find an external balance LT1 sized damper now for some reason. If anyone does find one though that would kick ***! These things are supposed to be 500 ft.lbs. capable!

 

the LT1 crank is interchangeable with the late model 1 pc main TBI/TBI/vortech small block cranks. its all the same ****. and unless someone put mallory in it to make it a 26oz imbalance, it should be 0.

 

True...somewhat. The LT1 cranks use the same weight arrangement (neutral damper, weighted flexplate/flywheel) like the non-LT1 variety. However, LT1 cranks which have in some cases the same part number as their non-LT1 counterparts are balanced differently from the factory due to the lighter weight of the pistons and rods as a standard 350. In fact, a 305 crank is closer in balance to the LT1 than a late non-LT1 350 crank (that's how light the LT1 rotating assembly is)which is why it's important not to mix and match cranks. My crank falls into a different category. It's not a GM crank even though it's in a GM crate engine, so the rules dont apply. If you looked at the damper you can clearly see the counterweight in it(which is removable too, I thought that was cool). The longer 3.8" stroke and 5.7 " rods made them hard to both balance internally and clear the pistons at BDC. This is because most late stroker cranks use 6" rods to clear the counterweights on the crank, and that's with a shorter stroke.

I'll upload some pics of it next time I get a chance. Yes, it's a funky arrangement, but is supposed to be good for making above average midrange and peak torque. If I can't use it I might just finish assembling it and build another 383 for my other car from scratch.

Yeah, I know my motor is jacked up... but it's all GM, oil pan to intake. LT1 top end, GM847, blueprinted ZZ383 bottom end.

 

when you get into rods and pistons you are talking about the spin balance of the rotating assembly. that is separate of weather the crank has an imbalance or not that requires a different balancer and flywheel.

i just know this from my ford stuff, but you dont run a 0 balance flywheel on a 28oz crank and then run a 28oz balancer. if the crank has a certain imbalance you need the proper balancer (actually harmonic dampener is the correct term) and flywheel/flexplate. if its a 0 balance motor you need a 0 balance flywheel and dampener. i have a steel SFI dampener sitting in front of me, along with 2 weights that can bolt into it to change of from (its current configuration) of 0 (or neutral) balance to a 28oz or 50oz imbalance. the weights are in a specific place on the dampener/flywheel. then you take the crank, dampener, flywheel, rods and pistons and have them spin balanced. you are talking about 2 different things here. and i dont know wtf is going on with your crank. see a machine shop.

if i had a crank like that and it honestly had the 28oz 400 sb imbalance (which i doubt and cola crank does) i would just have mallory slugs put in it. if its a 1 peice main crank, it should work in the LT1, other wise, i dont know wtf you have. im stumped by what your telling me. if you are trying to run LT1 heads on a non LT1 block, unless the coolant passages have been changed, it aint gonna work.

 

My setup is exactly the same (3.800 cola, gm pistons). My shop balanced it to the LT1 specs, and they had to add 1 or 2 slugs of mallory. It came to around 180$ for the balancing.

 

Give Cola a call about this.... I know there have been people selling these cranks for use in the LT1. I don't know what it is, but I'm sure theres a pretty reasonable solution to the balance issues for using this crank in an LT1. I bet you can get the right answer quickly from them

 

Yup, already ahead of ya

Yeah, it's weird. I already called cola and they told me about the damper being the same as a 400 sbc. Time to call some speed shops I guess...