I have to agree that at this time a lot of Billet cranks coming out of Moldex are not cross-drilled.
We did some testing at Ford and found (like David
R.) that cross-drilling the crank did more bad than
good on high rpm engines and the oil hole did little
on the low rpm engines.
A better deal is to time (as was mentioned) the oil
feed location so that the oil has built up a "layer" of sufficient thickness so that when the crank sees maximum loading the crank and the bearing material never touch.
With a cross-drilled crank you have pulsing flow in the oil passage like a tuning pipe on an organ.
This pulsing creates high and low oil pressure conditions at the bearing surface which would like
see steady flow and pressure.
A 3/4 grooved bearing with a conventional Moldex
type oiling strategy is a better deal overall.
I believe the cranks have duplicated some of that thinking.
JMO
Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught
Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward.
|