Bearings

[Lanse]

I was cleaning up my block today, and came across the main bearings. How do i get them out of there to measure them? they are real rough, looks like some kind of mineral deposit on them. Is there some way to clean them off and re-use them?? I would like to if possible, since i HAVE to be a cheapskate here, new bearings wouldnt be cheap but still i dont want to damage something by not doing anything??? any ideas are appriciated

 

[El Toro]

If the bearings look rough what do the journals on the crankshaft look like? If they're rough the shaft may need to be ground undersize. Your local auto machine shop can determine that. Hal

 

[Anonymous-0]

Lanse, like El Toro said, what do the main bearing journals on the crankshaft look like? The proper way to measure main bearing wear is BEFORE you remove the bearing inserts from the block. It takes some special measuring equipment that you probably don't have. The main bearing caps have to be reinstalled and torqued on the block with the crank removed. Then with an inside micrometer, or "snap' gauges and an outside micrometer measure the inside diameter of the bearings in several places. Then measure the crankshaft journal diameter. Subtract the 2 measurements (Bearing measurement will be bigger than the crank diameter) The difference will be the running clearance. Generally in the range of .0015 to .0025 or so. Check your overhaul manual. To remove the bearings they just sort of rotate out of the block. One side will have a little "tang" that sort of fits into a notch in the block. Gently push on the other end of the bearing until it pops out of the block. Clean the back off and it should be stamped on the back of the bearing with a part number and either "std" or +.010, +.020, etc. A - number means that the crank has been reground to that size sometime before. (Crank -.010, bearings +.010) This is of course assuming that that your engine does have replaceable inserts. If they're poured babbet bearings they aren't removable and you'll have to find someplace that is willing and able to work on them. Incidentally, I'm not too far from where you live. I'm near Middletown so if you have any problems my email is open.

 

[Anonymous-0]

Pull a couple of caps, take picture, post here, if they all look good, you can always buy some plastigauge (a wax thread of a known diameter, which is put between the bearing and the crank, then you reassemble, torque down to specs, then remove the cap, again, measure the new width of the thread, this measurement tells you the clearance). Be sure to mark your caps with a punch, so that they go back in the same spots that they came from! This method can be used for both mains and rods. If it aint too far from spec., you can shim the loose bearings, to tighten her up!

 

[JMS MN]

BTW- before removing them-mark them with a puncture wound punch or a number stamp. puncture wound punch- one mark on the front bearing, top and bottom halves, one side only. Two marks on the second one, etc. On older tractors, look first- they may be marked from a previous overhaul. You want to reinstall each bearing half in the same location, even with new inserts.