312 RMS Retainer


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By Countrysquire - 11 Years Ago
While cleaning and checking parts for my 312 rebuild, I noticed that the rear main seal retainer has some wear and marks on one side.  Is this normal?

http://forums.y-blocksforever.com/uploads/images/852ec59e-044f-4a9a-9eb5-2cf1.jpg
By Ted - 11 Years Ago

Two things come to mind.  The first is that the flywheel bolts were too long which came into contact with the rear main seal retainer.  The other is the thrust main on the center journal of the crankshaft is worn heavily permitting the crankshaft flywheel flange to come forward and contact the RMS retainer.  Most of the time it's just flywheel bolts being too long but look at that crankshaft closely anyhow.
By lyonroad - 11 Years Ago
I think you are right on Ted because I think I can see a faint circle where a flywheel bolt has been initially tightened up against the seal retainer.  Its about halfway between the two support ribs at the 6:30 o'clock position.
By Countrysquire - 11 Years Ago
Yeah, it's hard to tell in the picture, but the wear is in a circle and from the crank.  It doesn't seem like it will hurt anything, just wanted to check because I hadn't seen anything like that before.

For those who followed and helped with the other thread trying to figure out why it ran so poorly, I have decided to tear it down completely and rebuild it.  The wear at the worst spot in one cylinder was .001" beyond the .060" overbore, so I have elected to re-ring it.  Rod and main bearings all looked good, and I'm sure if I measured them with Plastigauge that they would have been in spec, but I will be installing new bearings as well.  Checking the heads, six of the eight have intake valves will allow a little solvent to seep through when the ports are filled.  I guess that I will disassemble the heads and lap all the valves.