Tractor Repair: Blow by, IH 1066, blow-by

Question
I have a IH 1066 that I'm doing some heavy duty bush hogging with. The tractor is not mine but the guy I'm doing the mowing for so I don't have any maintence history. The other day before I started I notice the oil level was a little low. I started mowing and noticed the tractor was blowing oil out of the blow by tube. I picked up a gallon at lunch and didn't even put it on the dip stick. I know it sounds like a broke piston ring but the tractor does not smoke and starts and runs perfect. Next step is to change oil/filters and start over. Any suggestions?
Thanks.

Answer
Since you don't know the maintence of this tractor it couldn't hurt to change the filters.
But it is cause for concern if it loosing that much oil through blow by.
How much oil did it take to bring it up to the proper level?
Has it went down anymore sice topping it off?
If the level hasn't went down since you have topped it off, there may not be that much oil loss.
There are occasions were I have seen an engine have considerable blow by and not smoke, but it is rare.
If it does have as much blow by as it seems to then it is time for an overhaul.
These are great tractors and will definitely be worth it.
I always do an oil analysis before starting so I'll know what to pay special attention to as I disassemble the engine.
Let me know what you find out.