Farmall c rod bearings

[farmallmitch]

Hello all, I recently replaced the rings and rod bearings in
my farmall c and ran into a problem. When I measured the
journals on the crankshaft they repeatedly measured
1.745. Standard rod bearings are 1.75. So I ordered the
.010 undersized rod bearings as I was told from a tech on
Steiner tractor parts. When I removed the old rod
bearings and looked at the stamp on the back, I realized
they were standard bearings but some were worn and
discolored pretty good. I went back on steiner and they
once again told me if I measured 1.74 on the journals to
use the .010 undersized bearings that I had bought. The
issue Im running into is when I dropped the first piston in
and torqued the rod bearing cap down (40-45 foot
pounds with the cotter pin style nuts, as I read online) the
crank shaft locks right up and I can no longer move the
crank. Even when jacking the tractor up to put it in gear
and spin the tires. But once I loosen the rod bearing cap
and take the cap off the crank and piston move as they
should. I applied assembly grease to the bearings before
installing. Does anyone have any advice on what I should
do?

 

[wore out]

Crank journals wear "egg-shaped", I would guess you are either measuring inaccurately or have measured the area of the most wear on an egg-shaped journal.

Best to have a "pro" measure up the crank and have it reground (if needed).

Also, the rods need to be professionally "checked" after the "tighten 'em 'til it locks up and try to force the engine to turn" incident.

 

[farmallmitch]

To clarify we did not turn it until it locked up. It locked up
as soon as the rod bearing caps were put on and torqued.
We simply just tried to softly rotate it with the wheels to
see if it was just tight. We never turned the engine until
it locked up

 

[teddy52food]

You would have to get the crank ground to use those bearings. Try & get a set of .002's & use plastigage to check them. If you would have used it on it this time ,you would have known it was too tight. Good idea to have the rods checked too. That one may be stretched. If your measuring is right ,you have .005 wear not .010.

 

[used red MN]

If the size change is from wear and not due to the journal being machined to that size you will be able to see or feel a step towards the outer edge of the journal. The step will be where the bearing is narrower than the journal so it does not ride on the journal at that outer edge margin. Anytime you have any visible wear like that you immediately know the crank needs reground or replaced. As woreout pointed out the worn part is almost guaranteed to be egg shaped.

Edit to add: Hopefully you know the bearing caps for both the rods and mains need to be reinstalled on the same mate or position they were originally in. The bearing alignment tabs usually are on the same side, as in both close to the same bolt. There is a possibility you may have damaged the rod but I feel it is kind of unlikely. The sizing of the rod ends on these old Farmalls is important, but not as critical as on a faster revving higher powered 6 cylinder unit. I have some checked you can do without involving a machine shop that will give you a pretty good feel if the rod end has been damaged, please email me if you want to discuss that process. If longevity is critical and you like to throw money at it go ahead and have the rod ends resized.

This post was edited by used red MN on 04/27/2022 at 11:32 am.

 

[wore out]

No use being defensive about it, we have ALL goofed, and more than once.

When the rods were tightened down on inserts that were too "small" the "big end" of the rods may very well have been "stretched" damaged.

You MAY get by with std. or .002" U.S.bearings as TfF says or you may NOT.

Trouble is if it DOESN'T work out you will have more damage and $$$ to repair than doing it correctly now, IMHO.

 

[farmallmitch]

I explained my problem to Steiner and they believe that they sent me the wrong bearings. The new bearings have no marks on them to identify the size. And I asked if they wanted the numbers on the box that the sets came in and they said it didnt matter, they believe they sent the wrong bearings that what I ordered.

 

[miangus]

Correct answer. I always checked rod oil clearance by assembling rods using a rod vice then miccing the crank and setting the bore gauge from the mic. The gauge will read the oil clearance when you measure the rod bearing. When using a crank that has not been ground to an undersize more care must be taken when inspecting the crank. Just using undersize bearings without careful measurement will result in connecting rod failure. At least use Plastigauge. It doesn't hurt to measure and then use Plastigauge too.

 

[rustred]

that will never never work. how can you put in .010 thicker brg. plus need .0015-.002 for brg. clearance. you are too tight by .007,... use standard brgs. or turn the crank. you cant listen to parts men. you should have had a mechanic double check your measuring.

 

[farmallmitch]

So you are saying I should buy the standard size bearings? Which are what I actually took out of the rod bearings. I was listening to the parts guys. I dont have a mechanic were on a farm and do it ourself. Never had this problem before. I also have multiple farmall cs so Im not trying to dump a lot of time and money into it by rebuilding and machining everything. Just want it to be a nice cultivating tractor for a few acres. Do you recommend just getting the standard size bearings like what I pulled out?

 

[J.Wondergem]

You need to use some Plastigauge on each thro to see what you need.

 

[rustred]

well yes, that the thing to do if you dont want to get involved with big money for a little tractor with little use. u had to plastigauge all the brgs. write that down on paper. 005 would be the maximum amount of clearance you want. so with these new standard brgs. u then plastigauge them and compare to your original brgs. if you are in the .002.003 range you are good. plus use a 40 weight oil due to extra clearance. ideal new is .0015. lets see you original brg.s. for wear. tearing something apart with out checking stuff u are pretty much in the dark. i know u said u measured the crank, but still need a brg. clearance.

 

[T.R.K.]

Your crank is .005 undersize.
.010 undersize would be 1.740. so your crank is .005 bigger than the hole in the bearing.
I don't think you can get .002 or .005 under bearings.

You really need to remove and grind your crank. Then your .010 bearings will work. (provided your crank grinder can center up on a journal that is .005 undersize already.)

 

[matthies]

I have to ask, how did you measure the journals, then removed the bearing to find the actual size?

 

[rustred]

it is not clear here what the original size journal is. he is talking about rod brg size. you need to know the original journal size then take the measured worn journals and make a decision. the brgs. would have to be installed in the rods, torqued to spec. them measured. that is why plastigauging them before teardown was the answer. that way u know whats going on. and he dont want to spend money turning the crank and i dont think he has to. a person needs the plastigauge spec. first. wait and see if we get some. you cant say the crank is .005 worn and even if it was it would be egged. there should be more wear on the brgs. then the crank. that is why i wanted to actually see them old brgs. we do not have enough info here.

 

[wore out]

"we do not have enough info here"

I think we do.

When the rods were torqued down on inserts that were too "small" SOMETHING had to "give", and that "something" would be the "big end" of the rods.

At this point, the chances are not real great of ending up with an engine that can be expected to hold together very long unless the rods are professionally "checked" and resized as needed, IMHO.

 

[caterpillar guy]

First a crank needs to be miced with a real mic not a set of calipers. 2 it needs to be miced at 90degrees apart to check for egging. If not more than about a 0.001 you could put STD bearings in with a 0.001or 0.002 shim under them and be fine. Probably the 0.001 would be best as that would shim up 0.002 clearance with the egg being still able to clear a bit. Yes you can do this. Parts men are not much good for something like fitting bearings unless they are from a machine shop in the first place. Then when you get the new bearings in there As you tighten them up turn your crank to prevent a problem again. Checking your oil clearance with the old bearings is not a bad idea though not really necessary if crank is miced like I stated in the beginning. You could tighten one of the next set of bearings up in the rod with no crank and measure to check the diameter.

 

[BarnyardEngineering]

(quoted from post at 13:24:06 04/27/22) So you are saying I should buy the standard size bearings? Which are what I actually took out of the rod bearings. I was listening to the parts guys. I dont have a mechanic were on a farm and do it ourself. Never had this problem before. I also have multiple farmall cs so Im not trying to dump a lot of time and money into it by rebuilding and machining everything. Just want it to be a nice cultivating tractor for a few acres. Do you recommend just getting the standard size bearings like what I pulled out?

Yes. Absolutely.

You NEVER put in "undersize" bearings unless you are having the crankshaft journals ground down to the new undersize dimension.

Also 1.745 is NOT .010 undersize. It is .005 undersize. .010 undersize bearings will not turn.

Again, if you are not going ot have the crank turned and ground, put in the SAME SIZE bearings that you took out. The bulk of the wear is in the bearings.

This post was edited by BarnyardEngineering on 04/28/2022 at 04:32 am.

 

[rustred]

well yes that obvious the brgs. are to small. i am saying we dont have proper measurements at the moment till he installs the same size new
brgs. and plastiqauges them so we can see what the actual clearance really is. its a patch job he wants.

 

[gene bender]

YES just get a new set of standard as the 10 over were too thick for the crank

 

[timcasbolt]

(quoted from post at 10:14:08 04/28/22) First a crank needs to be miced with a real mic not a set of calipers. 2 it needs to be miced at 90degrees apart to check for egging. If not more than about a 0.001 you could put STD bearings in with a 0.001or 0.002 shim under them and be fine. Probably the 0.001 would be best as that would shim up 0.002 clearance with the egg being still able to clear a bit. Yes you can do this. Parts men are not much good for something like fitting bearings unless they are from a machine shop in the first place. Then when you get the new bearings in there As you tighten them up turn your crank to prevent a problem again. Checking your oil clearance with the old bearings is not a bad idea though not really necessary if crank is miced like I stated in the beginning. You could tighten one of the next set of bearings up in the rod with no crank and measure to check the diameter.

o self respecting engine assembler would EVER stuff shims under a set of bearings. You'd have to be a junkyard hack to even consider such a thing.

 

[Fritz Maurer]

Why not?

 

[BarnyardEngineering]

(quoted from post at 07:44:33 04/28/22) well yes that obvious the brgs. are to small. i am saying we dont have proper measurements at the moment till he installs the same size new
brgs. and plastiqauges them so we can see what the actual clearance really is. its a patch job he wants.

If you're not going to take the crank out and have it ground, what difference would measuring make? Put the same size bearings in as you took out and be done with it. It's not like you're going to have too little clearance. You still might have an excessive amount, but it will still be better than what you had.

As you said, it's a patch job. Commonly done on diesel engines.

 

[rustred]

i guess your not a mechanic. you repeated what i already told him. that was the whole idea with plastigauge, to see if your at the top end
of maximum spec. or over it. he has not told us what his current clearance was which is nice to know.