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4k Crank Into 3k Block

Featured Replies

Hi people, Just a quick question.

 

Might sound a lil silly, but here goes.

 

Will a 4k crank go into a 3k block?

 

pretty certain they have the same mains bearings size.

 

Reason being, i have a 3k bare block here and want to know if i could use it for a 4k build. which will save me from buyin another block.

 

Only thing in concerned about is the extra crank throw.

 

CHEERS

Ryan

Edited by SLO-030

yes but with a lot of stuffing around. Rally guys used to do as they were stuck with the standard block.

  • Author

Stuffing around includes what sorta "stuff"

Yes it will fit. You have to scallop/ machine the sides of the bores for clearance for the big end, as it will hit. You also need to slightly modify the sump for the same reason.

 

You will need to find pistons to fit. A 4k block is 10mm higher than a 3K, therefore standard pistons will protrude that much. I used charade with custom made pins.

 

It's a lot of screwing around. Use a 4K.

  • Author

Yea, will just use a 4k :jamie:

 

Thought if i could use the block i have i would. but unless i build a 3k i can't.

 

Had a suspicion the scalloping would be required but if i need to use other pistons i wont bother.

 

thanks for the info Redwarf

 

CHEERS

Ryan

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