Thought I would just start a new thread to document my fun adventures of owning a 70 year old tractor. I drained the oil the other day and stuck my finger in the pan and could feel some sludge. I decided to drop the pan and found a couple cups of heavy sludge in the pan. The inside of the block though was actually pretty clean. I took off the valve cover and found quite a bit of build up there however. I scrapped and vacuumed most of it around the springs, but it is just a tedious task. The tractor has been run with non-detergent oil it's whole life. My father-in-law has sworn that it needs that and continues to need that. My understanding though is that if you were to run a detergent oil with all that sludge in place, it could clog up oil galleries and cause more problems. Well with all the sludge gone, that shouldn't be a problem right? I would like to run a traditional 10w30 from now on. Anyone have any thoughts on running some seafoam or other similar products with the oil to clean anything I missed? There is an oil filter on the tractor as well. I'm also thinking I should take off the oil pickup and clean that up as best I can. That screen had to of been sitting in the sludge and trying to suck all that up. This whole project is slowly snowballing, but I also want this thing to be reliable for another 70 years!
I wouldn't start using a detergent oil now. Your f-i-l is right, that the engine was never designed to run on detergent oil. IF you decide to go to detergent, use a 30 weight oil, not a multi weight. I believe it would get too thin once hot for the lose tolerances that it was built to.
Yep, clean the oil pickup screen too, while you are in there.
As for sea foam, if you run it, be prepared to change the oil and filter after a couple run periods to get it, and any crap it has loosened, out.
Be careful cleaning an engine that old with loose tolerances and wear. If you get it too clean, it may start burning oil and smoking.