As I was disassembling my 235, I noted some numbers on the back side of the rod and main bearings. the rod bearings all had 1950 CP FM 62 the mains had 2151 CP-U. FM 65 with rubber stamp.001 2154 CP-U FM 64 with rubber stamp .001 2154 CP-L FM 64 No rubber stamp.
Does this mean the bearings are Federal-Mogul bearings manufactured in 1962, 64 and 65. The 2151 CP-U and 2154 CPU-U/L are parts numbers. I have no idea what the rubber stamp .001 means.
Am I correct in how I'm reading these numbers?
Thank you. Chris
Rock49 aka C-Rodg work in progress 1956 Chevy 3100 261 engine
I wouldn't worry about the date, but the .001 is an under size for a well worn or heavily polished crank to raise oil pressure. I never used them because quite often they would get too tight when the engine was warm. Another practice was to use 1/2 .001 undersize and the other standard to give .0005 under size. It kinda looks like this is what someone did. I would either mike the thickness of the bearing with a ball anvil mike or use Plasti-gauge. If they are within spec, I would put them back where they from. Otherwise you may open a can of worms.
Several aftermarket bearing suppliers such as Federal-Mogul, TRW, Clevite, etc. supplied rod and main bearings in .001 and .002 undersizes to allow bearings to compensate for slightly undersize crankshaft journals without regrinding the shaft. It was necessary to measure the journals accurately to be sure they were worn round and not tapered before choosing to use that type of bearing. It was sort of like using .001" different shim thicknesses from side to side on Babbit rods to make a slight alteration in oil clearance. Jerry
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