I have 6.125 Rods and -9cc Mahle Pistons.. Im 99% sure I have a spun bearing.. If I decide to go back with a 4.00 inch crank can I use what I have already?

Will it change the compression?

If so what all do I need to change.

If not I will need:

Crank
New Rod and Crank bearings
New Rings?

Anything else?

 

Pistons are specific to stroke and rod length.

 

Ok well I see I will need new -30cc pistions to keep my 9.5 compresson

 

or get bigger cc heads...

 

I would probably lose more money on swapping the heads. There cnc ported and hand ported by Bo for FI.. I would probably lose 2-3 hundred on them..

The Pistons have 1500 miles on them.. I assume I would lose about 100 or so on them..

Hmm wait.. If I didnt change pistons that would save machine show money also.. Ill have to figure out which is cheaper..

 

you will be able to reuse your rods but if you don't have a 4" stroke crank to begin with your pistons will be way out of the deck.you still running the stock 3.622" stroke crank ?

 

Yeah I have the 3.633" right now.. I want to go to the 4" crank.. Cant you change the wrist pin place? Either way it would change my compression which is bad.

 

That must have cost a fortune to get a custom 3.633 crank!!! (Stock is 3.622).

No, you can't change the wrist pin location on the piston. Are you effin serious? If you get a bigger stroke crank, you need new pistons.

You can change your compression with the piston dish and with head cc's.

 

Nah.. Had a friend do it pretty cheap. Most people say the small change isnt worth it but hey every little bit helps huh. lol

I didnt know anything about changing pin location either but a sponcer on here told me thats all I needed to do.