Hi everyone, have a question regarding D2 main and big end bearing shells.
Have taken the crankshaft in for a regrind and the guy at the workshop has asked if I can find out the wall thicknesses for a standard size bearing so we can check the ones I have supplied which, from measuring with an internal micrometer, look to be +.020 on the mains and +.010 on the big ends.
The serial number of the engine is 3J 6591SP, 3 3/4 bore, crank pins are main 2.750 and big end 2.625 which I beieve is standard. The bearings I have came out of another engine serial number 5J4806SP and they are in good condition, the bearings out of the 3J engine have suffered from moisture due to being stood as has the crank which is why I need to have it ground.
Any help would be greatly appreciated.

Seems nobody is jumping on this and I have an idea why. I don't know if I can be of much help, but I'll give it a try.

I just went through all this same mess--bearing shell specs, used bearings, rusty journals, water damage on mains, you name it.

The machine shop I deal with has that shell dimension for just about every engine except Cat. They seem to be a breed apart with their aluminum alloy inserts. The Cat shop manual gives journal size and new-bearing clearance. All I can suggest is inside mike the big end or the main boss and do the math.

If your bearing shells are +0.010 on an used shaft, you're going to have a problem, or pretty close to it. If you are going to grind, you need undersize bearings and I sincerely wish you luck.

Check out my ongoing thread, early pages: assembly of a D2 5U engine and look for responses by timbo46. He just did the main & rod bearing job, had some manufactured. There was also a response from someone who had a set of J series undersize bearings, same as a R2 set I am told.

Yes, the J series is different, just the problems of supply are pretty much the same.

Jack

I did find the rod bearing size but have not quite yet been able to locate the main bearing size. the wall thickness for the rod bearings would be .162 for a std bearing. I will keep looking and I may be able to find the size of the mains.
Mike Mahler
Vintage Engine Machine Shop.

Cheers for the response guys, have checked out the D25U engine rebuild posts and there is some usefull stuff on there. Anyway looks like I am sorted now as we have done all the measuring and the maths and I have a standard crank, a set of -0.020" mains and a set of - 0.025" big end shells so its off to the grinders now.

When all else fails, take the inside housing bore, measure the crankshaft, subtract the shaft size from the housing bore. Take the figure remaining and divide by 2. This will give you a wall thickness with no oil clearance. That figure you will have to determine by the manufacturer or the size of the shaft. In most most industrial engines you can figure that you will have .001 of clearance for each inch of shaft diameter. So if you have a wall thickness of .250 and a shaft size of 2.000 your shell should measure .249 I hope this will help also.
Mike