F20 Farmall - T20 Crawler Rod Bearing Shim Info

fireballv82003 · Nov 30, 2014

Hey everyone,
I am getting ready to have the rods / rod bearings done for my T20 crawler.
I am using undersized bearings and having their ID turned just enough to fit my crank.

[color=red:934084a18d]I need some info for my machinist about shim packs for the T20 - F20 (same engine)[/color:934084a18d]

I looked on another old tractor site. A guy said his old federal mogul manual says each bearing requires two - 0.050 shims and two - 0.031 laminated shims.......a total of 0.131"......on each bolt. I copied this post from that site at the bottom of this post.

I got two NOS shim packs from a guy and they measured 0.131".

Another guy said shims needed to be only 0.031.

With 0.131 shim packs on the two used bearings, the caps crush the bearing and shims about right. On the new, unfitted NOS bearings, the caps don't crush the shims.....because I have not filed the bearing protrude 0.005 past rod half?? Am I thinking right?

*******HELP!, Does anyone have thant that old Federal Mogul manual? ****** or know who earl from illinois that posts here on the YT site.?

The IHC manuals (I have them ALL) don't mention this. Not even the repairmen's manual for the powerplant. Looks like these manuals were written by 7 year olds with really good drawing capabilities, but not much mechanical knowledge.....haha lots of pictures but not many detailed instructions one might need. Maybe everyone knew how to do this back then and I am the dumb one.

Below is post from YT - this guy had no email address, Earl from Illinois.
My old Federal Mogul bearing manual say each rod brg. requires a shim pack of which is made up of 4-.050 shim and 2- .031 shim laminated. That would give you .131 on each rod bolt.

Thanks
Mike Green
Durant, OK

36F30 · Nov 30, 2014

(quoted from post at 09:17:52 11/30/14) Hey everyone,
I am getting ready to have the rods / rod bearings done for my T20 crawler.
I am using undersized bearings and having their ID turned just enough to fit my crank.

[color=red:780de0626d]I need some info for my machinist about shim packs for the T20 - F20 (same engine)[/color:780de0626d]

I looked on another old tractor site. A guy said his old federal mogul manual says each bearing requires two - 0.050 shims and two - 0.031 laminated shims.......a total of 0.131"......on each bolt. I copied this post from that site at the bottom of this post.

I got two NOS shim packs from a guy and they measured 0.131".

Another guy said shims needed to be only 0.031.

With 0.131 shim packs on the two used bearings, the caps crush the bearing and shims about right. On the new, unfitted NOS bearings, the caps don't crush the shims.....because I have not filed the bearing protrude 0.005 past rod half?? Am I thinking right?

*******HELP!, Does anyone have thant that old Federal Mogul manual? ****** or know who earl from illinois that posts here on the YT site.?

The IHC manuals (I have them ALL) don't mention this. Not even the repairmen's manual for the powerplant. Looks like these manuals were written by 7 year olds with really good drawing capabilities, but not much mechanical knowledge.....haha lots of pictures but not many detailed instructions one might need. Maybe everyone knew how to do this back then and I am the dumb one.

Below is post from YT - this guy had no email address, Earl from Illinois.
My old Federal Mogul bearing manual say each rod brg. requires a shim pack of which is made up of 4-.050 shim and 2- .031 shim laminated. That would give you .131 on each rod bolt.

Thanks
Mike Green
Durant, OK

I think you are trying to use modern methods on this old girl and are missing the point of the shims. There is no "crush" on these engines. The bearings are babbit and "fitted" to the crank with shims. New bearings are scraped to just fit the journal. Then you lube them and install the rod on the crank. I usually hang them down from the crank as you don't want the piston in the bore while fitting the rod. The idea is to add or remove pairs of shims until the bolts are tight but the rod is just free to rotate on the crank with very little side play. Some use plastigage but I just set them by feel. It takes awhile to get this right, but you will find the point where the rod just begins to resist being rotated, then add back in one set of shims and your good to go. Install the piston in the sleeve and tighten the rod bolts, install new cotters in the nuts.

fireballv82003 · Nov 30, 2014

They don't "crush" like on modern insert bearings.
I realize this.
They do have enough crush to keep them in place. This is determined by protusion of the bearing past the parting surface.
The shim packs need to be OEM thickness so that some shims are removeable for wear - as intended by the engineers who designed the bearings.
Since I am basically going to end up with a STD size bearing in the end of the process, I need to know what the original shim pack thickness was.

I just bought the manual I was looking for off ebay.
Does anyone happen to have two .030 undersize NOS F20 Rod bearings for sale? I bought 2 a while back, doesn't hurt to ask again.

I did get a good piece of advice though, and that was to get the crank magnafluxed.

Nebraska Cowman · Nov 30, 2014

Do you have a brand new unworn crank? If not then
all specs would be meaningless anyway. Any listing
was for shims to be included with bearings. They
still needed to be adjusted to fit. And all the
cranks I've ever been around are worn out of
round.Adjust accordingly. Yes, All the old timers
KNEW how it was done. Books were written
accordingly.

Earl-IL · Nov 30, 2014

I have those old manuals. send me email & your phone number,best time I can call you. Earl

Duner Wi · Nov 30, 2014

My 1953 Thompson catalog says the shim pak Part # Y925 is 1/32 inch for T20 and F20.

rustred · Nov 30, 2014

if it has brg. inserts I would throw the shims away. get the crank journal size and resize the rods to that size with the new brgs.
I did this with my wk40 and don't have to worry about shims. that is why those old truck engines had so much trouble in the tractor cause they were always set too tight and would wear the babbit out and throw a rod out the pan.
those f-20, w-30 engines have a lot beefier rod so maybe it wont work. but worth looking into.
with todays oils you will never have to remove shims anyhow.

F20 Farmall - T20 Crawler Rod Bearing Shim Info

fireballv82003

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