Cub Engine Rebuild - Stuck crankshaft

[Smokeycub]

The rod bearing numbers must match the crank and the rod, not the engine. The later serial numbers had a wider rod bearing and would rub on the sides of the early s/n crank. The rubbing gets tight when you torque it.

I agree with the others, sounds like the wrong rod bearings. For what it's worth, you should be able to feel some lateral movement (end play) at the rod journal after it's torqued down.

Can you move the individual pistons in the bores, did you check the ring gap? did the machine shop turn the crank and sell you the appropriate bearings?

Ring end gap is critical for good ring wear in and good compression after the rings are broken in. If too loose they may never wear in and if too tight, let's just say bad things will happen to your block.

[Barnyard]

Thank you, Sir. I'm still a bit new to the Farmallcub site and appreciate the help with the nav & protocol.

That's no problem. I figured more would see it and not only contribute, but also learn from it.

[The Riot]

OK, I went to TM Tractor and some to the folks there to no avail. They no longer sell crank and rod bearings. The nice lady there referred me to Valu-Bilt and I spoke to those folks and they had no clue about different size (width) of cranks, connecting rods and cooresponding bearings.

Would I be able to gentle sand down the side edges of the bearings I have to allow them to fit properly?

thanks,
"The Riot"

[Eugene]

Would I be able to gentle sand down the side edges of the bearings I have to allow them to fit properly?

Auto parts store, machine shop that worked on your engine, Case/IH - suggestions as where to buy the correct rod bearings.

[bob in CT]

You have not posted the specifics on your crank. IF it was NOT reground, then the standard bearing size part number is 527-458-R11. Google that number and you will find them offered for less than $15. Hopefully that is current. If the crank has been ground undersize then you need to look up what you have. If you go tho (New) Manuals above, you can download a complete pdf of your tractor parts manual. TC37-F (1979) is the best one for you as the early versions will not show the later rods. Best to be prepared with the correct part numbers when approaching inexperienced counter staff or ordering online.

[John *.?-!.* cub owner]

They need the part number from the connecting rod to get the proper width rod bearing. At least that is what suppliers have always asked for when I ordered rod bearings.

[Clark Thompson]

the width of the bearing isnt the issue between now and old style rod. It the thickness of the bearing that causes the problem.I would suggest loosening each rod one at a time. Then torque one at a time. after torquing that rod see if the crank turns. Then continue on till you find the rod that is causing the problem. It could be a bent rod causing it to stop turning. if it is all the rods causing the problem then you need to get the bearings for the number indicated on the rod.Making sure all rods have the same number. I have seen engines with both new and old styl rods inside. Another issue that can cause a tight rod is the rod isnt centered on the piston pin causing the bearing to be too tight.

[ricky racer]

If I bought an "engine rebuild kit" that supplier is the first place I would contact if I had incorrect bearings or questioned the ones sent. Give them a chance to make it right. However, like Bob said, we still don't know what you have for a crankshaft or whether it has been reground. You need to know what you've got before you check into the bearings.

[ricky racer]

Here is a nice description on how to check bearing clearances

[The Riot]

Well it apprears that the mystery has been or is close to being solved, looking like I indeed had the wrong rod bearings for my rod and crank. However, the mystery has a little lesson with it. It also appears that my Cub has had some engine work or an engine replacement at some time in the past. The rods and crank P/Ns that I have don't match for the S/N on my tractor, so either I had the crank and rods replaced or I had an entire engine replaced.

At the time of this note I have new bearings on the way ( this was a pretty expensive error) and report back to everyone as to the outcome once I have everything back together.

Again, thank you for all of the help and guidance.

The Riot

[bob in CT]

What number did you base your order on? Engine number or tractor number? Very early on, the numbers matched but as replacement and service engines came into the production mix the sequences started to shift. Tractor serial numbers frequently follow replacement bolsters and the rest of the tractor does not match. For anyone else reading this in the future it is a good lesson to use individual casting dates and the 2 serial numbers to understand exactly what one is working with.

Glad the mystery is solved, now you can focus on buttoning it up.

[John *.?-!.* cub owner]

I was of the understanding that when a serial number was specified for an engine part, it was based on the engine serial number stamped on the side, and not on the chassis serial number.

[Clark Thompson]

These day with the tractors being so old one can not really trust engine serial numbers. It is best to to disassemble the engine to verify what internal parts you have. This is done by measuring the crank journels and inspecting the rod numbers. Also It has been a problem of mis matched main caps to the engine block in many cases I have run into over the years. Also I have found in sevrial engines that connecting rod caps Havent matched the rod. This can cause tight bearings and or mis alingned bearing that will lead to bearing seizing/spinning.

[ricky racer]

These day with the tractors being so old one can not really trust engine serial numbers. It is best to to disassemble the engine to verify what internal parts you have. This is done by measuring the crank journels and inspecting the rod numbers. Also It has been a problem of mis matched main caps to the engine block in many cases I have run into over the years. Also I have found in sevrial engines that connecting rod caps Havent matched the rod. This can cause tight bearings and or mis alingned bearing that will lead to bearing seizing/spinning.

Good advice.