I recently Purchased a Zen-noh 1501 Gray market tractor. so Im new to the forum. When I first start it up it smokes alot. after about 20 mins it seems to get better but it still smokes? is there an easy fix for this or do I need a rebuild? It seems to have plenty of power. but smokes up the whole neighborhood.
That sounds like the rings are worn. The way to test this is to do a compression test, which requires a diesel compression tester. Unfortunately, there are many thread sizes on the glow plugs, so you need to remove one of the glow plugs and either measure the size and thread pitch to see what yours are, or go to an automotive tool place or Harbor Freight and try to match it to one of the tester adapters. Diesel motors typically require 450+ lbs of pressure to operate within spec, around 400 or below means rebuild motor time.
Assuming you go that route, you can pull the oil pan, remove the rod bearing caps, and look at the bearings. There is some material called plastiguage which will measure the clearance in the bearings. If there is much wear shown, it makes sense to look at the crank bearings in the same way (drop two or more bearing caps) and decide what all needs to be done. Hopefully, an engine lower end gasket set, the bearings, and rings are you are good.
Thanks for the reply, I was hopeing for a easier fix , but kind of throught that is what it is. I will do a compression test. I ran it it today for 2 or 3 hrs it used or burnt a Qt. of oil. it dont leak just smokes a lot. what a bout valve guides? could that possibly be part of the problem. I dont know a whole lot about diesel engines. Im about to learn, lol.