MF 35 rebuild guidance

I purchased a 1961 MF 35 with the Perkins diesel with 2200 hours about 2 months ago. I've used it 8-10 times pulling a 5ft disc harrow and noticed the oil pressure drop to just barley in the green. After doing a quick search it appears the bearings are worn and I am going to need to rebuild soon. A few days ago I was pulling the disc and after about an hour the tractor just lost power and shut off. I cranked it back up with out any issues and dropped the disc back down. After about 50 feet it did t he same thing. I noticed oil coming from the dipstick, a little smoke coming from under the hood and smelled like a belt burning. I think the smoke and smell was a result of oil spraying on the hot surfaces under the hood. I cranked it back up and drove back to the barn. The tractor ran fine but I noticed oil blowing near the right front wheel. After I shut it down I saw oil dripping out of a tube that came from the top of the motor and ran down the right front side. It looked as if it was broken at the bottom. I am guessing this is the crank case relief valve? I am assuming that I will need to rebuild. My question is will an in frame rebuild solve the problem? Or do I need tobpuull the motor and do a complete overhaul? Any other suggestions? All advice is welcomed and appreciated.

Hello 1badMF,
You have a few things to consider before you repair your 35. Your information on worn bearings is correct, but you may also have a worn crank & oil pump to go with it. If this is the case, a full rebuild would be advantagous in the long term, while replacing worn cylinder liners etc. This poses your next question, do you invisage that the tractor will be kept for the long term. If your answer is "yes", a full, out-of-frame rebuild would be the way to go, IMHO.
If the answer is "no", most of the the bottom end bearings can be replaced insitu with an improvement in the oil pressure. The heavy "breathing" from the crankcase vent tube says that the engine has wear in the top end as well, ie. possible worn liners, also pistons and rings. If it's an early build, it may have "chrome" sleeves fitted, which are very durable and may just require honing. These parts can be replaced without a removal of the engine from the tractor, but from previous experience, I'd pull the engine and have semi-finished "cast" sleeves fitted and then bored to size. This way, you will end up with perfectly round, "true" bores to run in your new rings sets.
Honing and re-using chrome bores works well if the engine is placed under a solid work load from the get-go, but if the engine is used under "light" loads from the start, they can quickly "glaze" in the bores and from there, can be hard to "bed-in" from this point. Don't ask me why I know, lol!
Also, I'd recommend having the injectors serviced as well, as "dribbly" nozzles will flood the engine bores with fuel in your rebuilt engine. This causes the lubricating oil in the bores to be "washed" off these surfaces, adding the premature wear of the rings and bores. I never rebuild an engine, without having these fuel injector nozzles replaced.
Hope this helps, Evan.

Here is the "Bible" I always follow when involved with a Perkins 3 cylinder diesel:

All the best in your decision :

Bob. Owner operator MF FE 35 X 3 cylinder Perkins Diesel:

Thanks for the replies guys. I reevaluated
today. It fired right up but had some smoke
coming from the exhaust. Oil pressure was
good. Pulled the dip stick and a little
smoke came out and oil was bubbling out. I
didn't try to drive it or put it under a
load. I figured that was all I needed to
see. I guess now it's time to decide if I
am going to do it myself or have someone
else do it.