1939 B Engine Overhaul

I'm new to the engine overhaul business and would appreciate your experienced advice. I have the engine on a stand and intend to replace the rings. Tolerance on the rod inserts is OK, wrist pins and crankshaft seem solid. Otherwise, the engine looks pretty good, although I have no history and it wasn't running when I got it.
What I'm wondering is should I remove the crank and cam shafts to clean? Also, is it possible to clean all the oil passages without completely disassembling the engine? What else might I be missing?
Thanks for your help.

i rebuilt a b two weeks ago rod, mains, cam ,bearins pistons everything new in motor , make sure you keep up the sims on rods and bearings , how many are each side !!!!! and make sure you turn rods the right way when you go back together with it.

I do not know if you have the tools to do so but I would pull the crank shaft and mic. it or have it mic. so as to be 100% sure every thing is as it should be. Also if you do not plan to replace the sleeves have them mic. to be sure they are not egg shaped. Better to spend a little more when you have it opened up then to put every thing back in and have to open it up a second time because something is not correct. Ya I have done them both ways and had luck both ways

Which way do the rods go and what is the piston pin bolt torque?

Just what do you call an overhaul?
How did you check the bearings to know that the clearance was OK?

You can pick thru the pictures at the link or check in other Allis tractor and engine albums for more detail.

If you don't mind getting wet you can get the oil passages in these little engines kinda clean with a power washer after you are down to a bare block as seen in some of my albums.
The real clean blocks need to be hot tanked with high pressure washer in the tank.
Picture Link

The wrist pin bolt torque would be from 35 to 40 foot pounds. If you get them to tight it can cause the rod to break at the wrist pin.

In the picture below the center of the engine is at the right. You can see the offset bolts on the caps.

bob, i have checked bearings and crank and ended up reusing them, reshim as needed. It is possible that crank and bearings are fine... one thing i would do for sure is replace the rings. while in there, pull the liners out, clean out the water jacket (will be full of crid), and put new o-rings on the liners to reinstall. you sure dont want a water leak a year after overhaul!

bob, i have checked bearings and crank and ended up reusing them, reshim as needed. It is possible that crank and bearings are fine... one thing i would do for sure is replace the rings. while in there, pull the liners out, clean out the water jacket (will be full of crid), and put new o-rings on the liners to reinstall. you sure dont want a water leak a year after overhaul!

Thanks for everyone's comments. Pictures were great Dick L. Checked the rod insert with plastiguage. Guess "overhaul" is a bit of a stretch since all I intended to do was replace the rings. I'll now pull the cam and crank shaft and check tolerances and proceed from there. Wish I had a sleeve puller and set of mics.

if you bought oem rings you could stick one in the cylinder and see what the ring end gap is if you dont have a bore gauge. i would be willing to beat though it needs sleeves also never seen a piston that had been run for years that hadnt shrank some also. imho

Bob, it really depends on what you're going to do with the tractor and how good of a job you want to do.
As far as I'm concerned, I never reuse pistons, rings, sleeves, and bearings. I always completely disassemble the engine and have everything hot tanked. There will be sludge and crud in places that you won't be able to see. I go through an engine fully and never cut any corners.
If you just plan to drive it in a parade, you can get away with rings and bearings many times. I would still have it hot tanked and be sure to have new cam bearings installed. The oil pump uses the hollow camshaft as a gallery and it is filled first. If the cam bearings are loose, it will have low oil pressure and it may not send enough oil to the rockers.
These engines use a bypass filtration system meaning only part of the oil pumped is filtered. The filtered oil is dumped back to the pan. Unfiltered oil goes to lubricate the engine. This is why I believe it is so important to have the block thoroughly cleaned. After hot tanking, use a rifle bore cleaning brush through all of the oil passages. You will be surprised at what the brush will loosen and compressed air will blow out.