Quote:
Originally Posted by George Miller
One problem is it is a long ways for the oil to get to the back of the bearing with out pressure oiling. The way I fix the problem is a oil groove in the upper bearing.
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George, I tried the same thing by extending the oil "wells" along the seams of the two insert halves. I extended the well (both sides) to within .25" of the back end of the bearing. I put the engine back on the dyno and had the same failure on the first heavy pull. Granted, placing a groove at the top may be better than both sides but I did not try your method. At this point, it is not something I am going to try as I have found a solution that works for me....more clearance.
It was at this point, I invested in a Sunnen precision honing machine and increased the clearances.
No problems since.
FYI: This experimental engine had a Burlington crank, Lion Speed head III delivering north of 80 hp at 3000 rpm. So the temps and pressures were beyond normal Model A. A wisp of smoke was coming from the bellhousing as I finished the first pull and when I cut the throttle, the rear main locked up. (Strike Two!) The rear journal cleaned up, using muriatic acid, with no damage.