Rod bearings

[Brodalick]

My rod bearings measure.006 using plasti gauge and I have quite a bit of movement. Would replacing them with .002 under size really help any?

[Eugene]

You need to measure each of the bearing journals. Once you know their diameter, you can order bearings.

[Brodalick]

I see bearings come standard, .002,.010,.020 etc. I know .010 are way to tight cause I tried them, and i know the crank needs to be turned in order to use them. Standard are little loose and i hate to disassemble to have crank turned. So the .002's caught my attention.

[Smokeycub]

Considering the recommended rod bearing clearance is .002" to .003" the simple answer is yes. I recall there is normally noticeable rod end play which may feel like loose bearings. Given everything else is perfect (not out of round) the .002" oversize bearings will be fine. IMHO I would say however that your 60 something year old crank would benefit by being turned down. An easier thing to do if you already have the tractor split.

[Brodalick]

That's the other reason I looked at the .002,'s. The tractor is not split and the garden is waiting patiently for me to get it fixed.

[tst]

how worn are the bearings now that you measured with?, spec is .002-3, if they are in good shape .002 under will not bring it into spec

[Smokeycub]

Of course Tim is right, they will not be in spec. I'm saying .004" clearance is better than .006" and only .001" out. When I did mine a few years ago the rod journals were at the max allowable and plastigaged at .003" with the old bearings and yet had a cold knock and oil pressure was at the edge of the red zone when hot. I put in new std bearings which plastigaged at .003" as well, and no more knock. I replaced the mains at the same time which had .006" clearance and the max journal diameter, new std bearings brought them back to .003". Oil pressure has been great, many hours and 3 years later still going strong. Yours will be just over spec. but dare I say, I think you'll be alright. To do it right though you should have the crank turned down.

[jsfarmall]

Measuring the crank will be the number 1 priority. If your crank is wore .001 and bearings wore .003 there is .004 of your play. More than likely your crank is wore more than that but even more likely your bearings are wore more than the crank. If I was in your position I would measure good and go with .002 under. Cubs these days typically don't get the work they once got. 12 hours a day of hard work. Now they might get 12 hours every 2 weeks in a garden. Just keep in mind if you ever tear down the engine for a winter rebuild turning the crank might be a good idea.