balancing a crank.... is it necessary

99eclipse420 · Aug 9, 2011

hey guys, im getting my enternals and gaskets tomorrow and so I can finally go to the machnine shop and get the motor bored, but is it necessary to balance the crank I blew a rod bearing and it wasnt even that bad of a blow just really warn down. So new pistons and im re surfacing the rods just to get rid of any imperfections, so over size rod bearings. So should I get the crank balanced or no Ill be putting new rods new pistons and a 2.2 stroker kit in in 4 months when I get back from a job. Thanks for every thing guys... and or females.

Lambiablo · Aug 9, 2011

With spun rod bearings there is definitely a chance that the crank will need to be shaved to clean up abrasions on the journals, and in turn you would have to run oversize rod bearings. Balancing may not be totally necessary depending on how scarred up the journals may or may not be. When you say stroker, do you mean stroker rods and pistons or crank as well?

99eclipse420 · Aug 10, 2011

I do not see or feel any scaring on the crank and I already plan to go with over size rod bearing and as for the stroker kit link for the stoker kit

BogusSVO · Aug 10, 2011

you need over sized rod bearings when you have the crank down.

when rods are resized, a small amout of material is removed from the rod and cap mating surfaces and the big end honed back to factory spec.

so if you have a crank that is std and has been just polished, and resized con rods, you will need std bearings.

are you doing a BSE? if you are not, and keeping the enging close to stock for now, the factory balance will be fine.

Zack Huffman · Aug 10, 2011

Lambiablo said:
When you say stroker, do you mean stroker rods and pistons or crank as well?

You can't increase stroke without changing the crankshaft, or at least having it offset ground.

BogusSVO said:
so if you have a crank that is std and has been just polished, and resized con rods, you will need std bearings.

This.

BogusSVO said:
are you doing a BSE? if you are not, and keeping the enging close to stock for now, the factory balance will be fine.

It's a 420a, so no BSE.

BogusSVO · Aug 10, 2011

delta448 said:
It's a 420a, so no BSE.

doh... I knew that, more used to talking to the 4g boys that the 420a boys....

richard33 · Aug 10, 2011

This kit consists of the following components:

Brand New Forged 90mm Stroker Crankshaft
Eagle Connecting Rods
JE Piston Kit w/Ring Set
ACL Engine Bearing Kit ( Rods and Mains )

It says it comes with a new crankshaft???

BogusSVO · Aug 10, 2011

delta448 said:
You can't increase stroke without changing the crankshaft, or at least having it offset ground.
QUOTE]

^^^ This

there is only 2 ways to increase displacement, a bigger bore or a longer stroke

changing just the rods and pistons, can give you a long rod engine but not increase the displacement of it.

for "common" refreance the 350 chevy comes with a 4 inch bore and a 3.480 stroke and a 5.7 con rod

now if you do the simple 6 inch rod swap the pistions will have the wrist pins located closer to the ring pack, the 6 inch rod has chaged the rod to stroke ratio with no increase in displacement.

now, we take the same 350 chevy, and pull the crank/rods/pistons
we keep the 4 inch bore but replace the crank with a modified 400 chevy crank that has a 3.750 stroke, you now have the 383 CID engine

Lambiablo · Aug 12, 2011

delta448 said:
You can't increase stroke without changing the crankshaft, or at least having it offset ground.

This.

It's a 420a, so no BSE.

Yes I am aware of the need for another crank to build a stroker, I was just a little unsure where he was going with it. Since he is talking about balancing the original crank despite the fact that he is planning on doing a stroker soon.

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balancing a crank.... is it necessary

99eclipse420

Lambiablo

99eclipse420

BogusSVO

Zack Huffman

BogusSVO

richard33

BogusSVO

Lambiablo

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