The edge of the Lower (ie. cap rear main) bearing looks to be about 1/4" away from the back of the crank, so the bearing will never touch the crank. The machinist did not remove the dowels, therefore it looks like it has
probably been this way since new. The rear main cap has never been changed, it is original.
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I examined the bearings a bit closer.
(i) The rear main upper bearing shell has two grooves. The groove nearest the rear main seal varies in width about .003-.004 from side to side. It is slightly wider on the side I have marked as Right Side.
(ii) The width of the bearing face (face between rear groove and back of bearing) varies in width approx. .020" from side to side. Again, the bearing face is narrower on the side I marked as Right.
(iii) I think this slight variation in groove width and bearing face width makes the alignment a bit more noticeable.
Note, the rear main bearing is a fully grooved Clevite 77. There is an Upper bearing and a lower bearing. The Upper bearing is in the block and the lower bearing is in the cap.
Note, all other main bearings in the set have only Upper grooves.
On closer inspection, I have noticed that a few of the other rear main lower bearings are not erfectly centered in the main caps. They protrude a tiny bit from the the caps...a very tiny amount. The bearings in the block all seem to be centered perfectly. I think what makes the rear main alignment more noticeable
is the grooves. As Clevite 77's use a fully grooved rear main bearing.
I did put on my torque wrench , which goes down to 25ft/lbs. The crank was taking less than 25ft/lbs to spin, but not sure exactly how much torque. The crank does spin easily by hand.
I am going to leave this rear bearing as is and assemble the engine. From the feedback I have received, I am satisfied that this will not affect the durability/performance of the
engine. Thanks for your feedback guys.
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