Counterweight shape for less windage

[Rick360]

I have seen crank counterweights machined in different ways (knife-edged) to reduce windage HP loss. Some come to a sharp point on leading edge, some are rounded like a wing. Some are angled on trailing edge and some are squared off on the trailing edge.

I have done this to several of my own cranks. From looking at the crank and what it is doing in the engine, I "think" the best shape would be rounded like the leading edge of a wing and square on the trailing edge to keep the air/oil from returning back in front of the crank on the next revolution. This may be different for dry-sump with vac. pump than wet-sumps.

Has anybody done any actual dyno or track testing to verify what works best? Any other comments about how cranks they have seen are done? I am particularly interested in wet-sump apps but would be curious about both.

Rick

[CNC BLOCKS]

Rick
On some the engines we build we load the front and rear counter weight up with mallory and O.D. the counter weights back to get rid of windage it seems to make the engines respond quicker and we use a lot of cranks from Kings Crankshaft in Denver N.C. and on some of the engines we use the Honda rod 283 mains.

A few weeks ago I took a trip down to N.C. and stayed with Rick King and his family and did the tour through his shop and was quite interesting to see a crank made from a round piece of billet that was to be used in a LS-1 engine and all his cranks have the bull nose on the leading edges of the couter weights.