15-09-2020, 02:01 PM
(15-09-2020, 01:22 AM)Bob Culver Wrote: Plastigauge is intended for modern bearings with a definite clearance. Likely to damage a bearing with no clearance.I'm a bit surprised by this statement as the documentation I have from Hoyt recommends the same clearance per inch diameter of the crankpin using their babbitt style metal as Mahle etc. do for their modern shell bearings. This ends up as being about 1 and half thou' on an A7 motor, When I've bored metalled big ends for splash fed motors I aim for at least a couple of thou clearance on the basis that more oil flow equals more cooling and less chance of a "run" bearing. Anyone who has stripped a motor with "a bit of a big end knock" will know that the clearance on the dud rod to the crankpin will be measurable in fractions of an inch rather than a few thousanths.