Knife Edge

[Anonymous]

what are the pros and cons of a knife edged crank?

 

[DYNOED250]

from what i have heard, it flicks the oil away and toward the bigends to keep em cooler ????. Its also slighlty lighter, and id think would cut through the oil easier if there was any splashing up.
I wouldnt think they would be any weaker as the knife edge is on the counterweight.

 

[Anonymous]

Purpose is to cut down on internal friction. The crank webs are usually polished also. That crank spining through oil & vapor creates a lot of drag.

 

[xctasy]

All 250's have a windage problem because the crank is like six big horses arguing for feed from the same trough! Little oil globs about 60 microns flick all over the place, ensuring the oil supply stayes in a humid mist above the oil pick-up. If your going over the 5300 to 5400 rpm barrier, I'd look at doing it.

The Holden L6 and Morris Cooper boys have favoured knife edging for yonks. If you've got the time, do it!

 

[Anonymous]

what dynoed250 said is correct, it allows the oil to hit the big end so it keeps it cool.

to get it done it isnt cheap and u have to be careful because if u hit a journal, throw out the crank and start again