John Deere A rod and crank problems

[Devon B]

My daughter and I have been working on a 1950 JD A for sometime and ran into an issue with the rods and crank. The crank is original to the motor but the rods and pistons are not. They were beyond repair. We used plasti gauge and got the .003 per the service manual but as we turned the flywheel there is a spot it would get really hard to turn (had to use big pipe wrench to turn it. Also, there is certain spot the rods are actually "wobbly" on the crank. I thought the crank may have been egg shaped so I measured it the best I could vertically and horizontally on both journals. For #1 I got 2.9323 vertical and 2.9345 horizontally. On #2 I got 2.9385 vertically and 2.94 horizontally. I didn't think that was to "egg" shaped but I may be wrong.

Can someone help me and explain how I can measure the rods because it has shims. Also, if I am going at this completely wrong please tell me. I would prefer not to remove the crank because it is a major undertaking. Anyone's help would be graciously appreciated.

 

[Lynerd]

Devon B Best way to adjust for clearance is remove shims till it gets tight then add one shim. Lynn

 

[Mike(NEOhio)]

The out of round doesn't sound too bad but they started out at 3.000 to 2.999. That's an awful lot of wear. Take the rods out and put the caps on
with the shims just as they were. Torque the nuts then measure the ID vertically and compare that to the IDs on either side. Measure them from rod to
cap on either side of the shim packs on both sides. I just went through this with mine but there was barely any wear on the crank. One rod was good
but the other I found one nut was down firm but not torqued. When I touqued the nuts it was tight on the journal. I added a shim on each side and it
was good.

 

[Loosehandle]

It sounds like that crank has been ground
and the rods are not the right size for it.

 

[Fixingfarmer]

So I had a 4 cylinder once with a slightly bent crank after a liner froze. The owner wanted to keep cost to a bare minimum. every time Id roll it over with one of the rods in it would get tough. The fix was fairly simple although not what Id call a high quality repair. I took the offending rod out and glued a
200 grit sandpaper to the welding bench. Then shaved the side edge of the connecting rod down while it was bolted
together with its cap to keep it pretty square sliding it back
and forth paying attention to machine marks. Worked like a
charm and the tractor is still in use. The idea came from an
old tractor puller