MF1100 Engine Overhaul Questions

My 1100 we cobbled together a few months ago now needs and engine overhaul. Long story short, after about 40 hours of run time on the engine, it tried its hardest to seize up.

I had what I thought was a good recently rebuilt motor that just needed a new set of bearings due to diesel in the crankcase. That wasn't the case as water had somehow gotten in it and ruined it.

Now I'm not sure which way to go. I had plans to vat, overhaul and paint the engine since it was out of the tractor. I want to paint the tractor, and the engine seemed the most complicated part. So I figured now was a good time to do it.

It seems that the engine that we had as a back up had low oil pressure at idle, even after being rebuilt. Are the oil pump and main bearings the major things that contribute to oil pressure? The machine shop we spoke with says it doesn't use cam bearings. I don't want to rebuild this thing without correcting that. The engine in the tractor had great oil pressure even as it failed, and part of me thinks I should just rebuild it. The crank in the back up motor is too worn at the thrust washer and will have to be repaired for use, I'm unsure of the condition of the crank in the tractor as we haven't torn it down yet. I can get one that's been turned 10/10 and is ready to install for $450.

I guess I said all that to say this. What steps do I need to take to correct the low oil pressure? Or would it be easier to in frame the engine in it and deal with painting it in frame as well?

Not too much oil goes to the camshaft/head, and they usually don't wear. I would use the engine that's in the tractor, if it did spin a main beaing the block can be line bored, if it didn't spin the main bearings then you don't have to have it line bored. Have the crankshaft journals checked for wear, and cracks then you can either have it turned, or replace it. If it has spun rod bearings either replace the rods that had spun bearings, or you can have a machine shop resize the big ends of the rods using new rod bolts. As for the oil pump I would replace it with a new one. That would be the way I would do it.

Good to know that the cam doesn't see a lot of wear. I'm beginning to lean towards using the engine in the tractor like you suggested. I'm sure I have a spun rod bearing because the engine started knocking before I shut it down. I have enough rods to make a good set though. I hadn't planned on replacing the oil pump because I figured that the only ones I'd be able to find where chinese made copies and frankly, I'd rather use an old original than a chinese one. However, it seems I can still buy one made in England for around $100, so I will probably go that route.

Thanks for the reply.