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
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Crenwelge, The date is more of a curiosity, potentialy an indicator of when past work was done. Of course it only realy tells when the bearing was made, they could have sat on a shelf for decades before instalation. As for the can of worms, it was already open. I have taken the engine down to a bare block. All the bearings were worn down to the copper.
So. This is a way to get more life out of a crankshaft without grinding it? Would this have been seen as a get by type of fix, or good as new?
Chris
Rock49 aka C-Rodg work in progress 1956 Chevy 3100 261 engine
A company named Rebuilders choice makes .001 under size. Kanter sells them under their house brand and Falcon Sales http://www.internalengineparts.com sells them on their eBay store. I would go back with .001 where .001 was previously. But I would Plastigauge them to make sure you have enough clearance. I like to install the thrust bearing last and try to rotate the crank before installing it. Sometimes the thrust bearing causes a drag that has nothing to do with crank journal diameter. You can measure thrust clearance with a feeler gauge. It looks like your rods are standard. I would go back with standard. Although the specs call for .001 clearance, I never put one together with less than .0015 and approaching .003 doesn't hurt anything. With today's lubricants you are not going to experience the wear we experienced 70 years ago. And oil pressure is really not that important. What is important is that you have enough clearance for the oil to get there. The main thing is that when you put it together that it turns freely. Otherwise you have a problem. The fact that you can see copper really doesn't mean anything. There is a very thin layer of babbitt matterial over the copper. Your engine probably isn't near as worn out as you think.
