i have a already built 383 motor sitting here, i want to put a new crank in it however, the one i have my eye on says its for external balance. i am pretty clueless to this new balancing terminology. if i buy this external balanced crank, what would i need to do to make it work in my engine good? the footnotes says it requires a 400 harmonic balancer and stock flexplate. (is this a stock 350 or 400 flexplate?)

can i just bring the engine and crank to a shop and feel confident enough they know what they are doing? thanks!

 

nice new sig it fits ur car perfectly

 

Internal is better.
So is it a 400, or 350 crank? I don't think a 400 dampner & flexplate will fit a 350 crank and vice versa.

My 388 is all 350 to avoid part compatibility & clearance problems.

 

i'd avoid external balance because you'll be stuck using external dampners and flywheels, they're harder to find. i'd take the rotating assembly to a shop, less dampner and flywheel, and tell them to balance it.

 

so i can just buy this exact crank

http://store.summitracing.com/defaul...5&autoview=sku

and a shop can do the rest?

 

the only problem is its a One peice rear main seal, so i have to get a special crank, and seems they are only avail with the description says external balance.

 

As stated above, you want an internally balance crank with a single rear main seal. Also, if you plan on spinning the assembly above 6,000 RPM and make good Hp, you should buy a forged crank.

I believe that you can get a forged single main seal 383 crank having 350 journals from Callies, their Dragon Slayer piece. But there are several other companies that have this type of crank, I think that Eagle has one also, as well as, Scat.

If you got to stay on the low cost side, then get a cast crank.

 

if you know of an eagle crank that is one peice rear main seal, and internal balance, plz link me the only ones ican find are external. what is the disadvantage of external balance anyways?

 

Take it to a machine shop and tell them to internally balance it. I had my 1 piece 383 Eagle crank external balance internally balance by a good machine shop. Wasnt very cheap due to the amount of mallory then had to add but is it ever silky smooth now.

 

www.callies.com

Also, use a search engine on the web,,, you will find several performance shops with 1 pc rear main seals and internally balanced.

And: www.scatcrankshafts.com

 

ive heard bad about scat and will not use them.

 

another question popped in my mind, if im gonna have the crank internally balanced anyways, should i still follow thier advice online with using the 350 flexplate and 400 damper?

 

If it's internally balanced, you'll use a 350 flexplate and dampener.

 

ooooh ok

why cant i just have it external balanced like it says?

 

You can, if you want.

 

how come everyone insists on having it internally balanced?

 

So you don't have to use the counterweighted damper or flexplate.

 

but if it was ment for external balancing with the 400 crank wouldnt it be alot easier for the shop? since the balancer has the offset in it.

 

Absolutely.

 

thanks, i think ill just purchase the crank and the correct balancer/flexplate and take it to the shop and tell them to balance it

 

You mean take it to the shop with your rods, pistons, pins, rings, and bearings for balancing, right?

 

yes all that is already installed in the block with a crank. but it needs a new crank i dont like this one, looks like swiss cheese.

 

It will all need to come out of the block and go in for balancing.

 

do i have to bring the block itself, in?

 

The rule for balancing is if it moves, they need it. Crank, rods, pistons, damper, flywheel and at least one set of rings and rod bearings.

You don't need to take the block for balancing, but you might want them to clean it up and hone for new rings while it's apart.

 

this block was already balanced and assembled, never ran, im removing the crank and replacing it with a new one, are the pistons and rods and all that balanced in conjunction wit each other or will they be offset to the crank?

 

If you have the original bob-weight data from when it was balanced before, they could use that instead of weighing everything again and you'd just need the crank, flexplate and balancer. Otherwise it all goes in.