Crank

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sublimeswinger

sublimeswinger

SUBLIME Senior Member
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What does it mean if your crank is cut 20 under? What kind of power or torque does this give and why would it be done? The motor is a 318
 
has nothing to do with power or torque, it means that much was cut off the crank journals to repair them, oversized bearings are then used.

sublimeswinger said:
What does it mean if your crank is cut 20 under? What kind of power or torque does this give and why would it be done? The motor is a 318
Click to expand...
 
It means the bearing surfaces were cleaned to.0200 under their original size. Means you'll need a 20 over bearing set. No difference in performance.
 
Ok, not sure i get it , where is it shaved? If it is a repair and they cut from the actual "crank" lobes, would that not change the stroke? im confussed
 
RedFish said:
It means the bearing surfaces were cleaned to.0200 under their original size. Means you'll need a 20 over bearing set. No difference in performance.
Click to expand...

Sorry i took a long time to post. That makes sense. so they surface where the bearings are. got it . Thanks
 
when a crank is turned it requires undersize bearings not oversize!!
as for power?? anytime you reduce bearing diameter, you reduce friction and bearing speed. that's why eagle rods have honda size bearing ends for chev 350.
 
It is true that a small journal has less friction and bearing speed but a thicker bearing shell is not desirable for higher HP or RPM because it will not be a stable as a thinner bearing shell.


Chuck
 
Oh I thought we wanted .0400 clearance between jounal and crank. LOL
nic pickers !!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
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