Knife edged crank, worthwhile mod?

[GAspeedProtege]

What do the experts think? I'm already in on the MAM piston and rod GB, so since my motor is going to be apart I thought this would be something useful. Is it worth it?

 

[jflo]

it might be since you're reducing the amount of friction caused by oil on the counterweights and such...but not really sure since they do this mostly with cars that are designed to rev high since this reduces the mass of the crankshaft too

 

[Pretzellogic]

I would say that on a B18c5, or other engines with a high redline, this is a good mod. On our engines, not so much. Probably not worth the cost.

But I am an armchair mechanic

 

[jaje]

in theory knife edging tapers the crank and will reduce rotation mass (making the engine spin faster) and increase the oil flow by reducing resistance

it has more advantages on a high revving engine but will help even on low revving engines like the fs-de

 

[jred321]

if you've got it out already, i'd say go for it. it's not worth it otherwise, but if it's right there might as well

 

[ddogg777]

Don't do it, cost-to-benefit would be to great. I have seen the lobes on our crank and they are not very wide compared to the V8s that are knifed. Plus, I understand that a new concept is to round the leading edge similar to an air foil, not knife it. This has better fluid dynamics than a sharp leading edge. Knife edging helps also to direct the splash of oil towards the oil galleys, if you think you need that.

 

[DSMConvert]

hmm actually this is a very prevalent mod on DSMs...as stated it allows for a faster and easier rotation of the crank, much like a lightened flywheel. If you have the engine already apart its worth the extra trouble, but dont take your engine apart solely to do that.