16v KR crank knife edging

[Preen59]

Hey guys,

I've got myself a 1.8 16v that i'm currently working on and i was wondering about knife edging the crank.

I'm a machinist/ Toolmaker and i've got a big enough lathe and other equipment in my workshop to do the job- that's not a problem, but i was wondering if anyone on here has info on how much material to take off aswell as angles and dimensions?

Some pics would be great too, if anyone has any.

Thanks,

Chris Preen.

[velly_16v_cab]

i have a friend back in the uk how does this, i will email him and see what info i can get off him for you.

i used to have a write up on it in a mag but that back in the uk too lol

[Preen59]

Thanks for the quick reply, Velly. I'd appreciate it very much if you could get that info for me.

[VW Convert]

Hey guys,

I've got myself a 1.8 16v that i'm currently working on and i was wondering about knife edging the crank.

Hi Chris,

Pardon my ignorance, what is knife edging?

Cheers

George

[KI11Z]

instead of the bulky crank ends, you essentially "grind" it down to create a "knife edge" so that it can cut through the oil more efficiently creating less drag as well as lightening it and thus releasing valuable hp!

Attachment 1317

Attachment 1318

[velly_16v_cab]

Knife edging the crank is mainly for increasing horsepower by reducing the windage loss in the crankcase while reducing the crankshaft's rotational mass, allowing for the engine to accelerate faster

the top on is std, bottom one has been machined

[twin eng, twin turbs]

Hey Chris, knife edging reduces the "parastatic friction loss" as the crank cuts through the oil in the crank case and sump. You need to match the angle of the web between the main bearing to the big end bearing when machining the counterweight, but avoid machining the web between the bearing journals as this will obviously reduce the strength of the crank. Lighten your flywheel aswell and ill dynamic balance it at work for you to 0.1 of a gram and linish it to A tiny amount of low end torque and smoothness will be lost at low rpm due to the weight reduction but its not an issue in comparison to the top end power gain!!!

[rayray086]

Wow good info guys. I didn't know what knife edging was either until now. Just wondering, is there a more technical term to it?

[velly_16v_cab]

no, lol

[gotrice]

Reading through I cant believe that people still think that lightening the rotating mass gives you more power. It reduces the time taken to get to your peak power but you dont get any more horsepower. And yeah I know that I am going to cop a burning now lol.