HI, I've got a perplexing problem with an engine in my Case 446. We had someone rebuild it, got it back and started it, it ran awesome for a few, then blew oil out the exhaust and all over, they looked at it again, ran it a couple of hours, then it did it again. Long story short, I got my $500 back and I just really think it has to be something simple, it runs great, then suddenly blows oil again. Help !!!!!