I became the proud owner of a BMW 2002 a few years back when a friend of mine said to me “if you can get it out of my shed you can have it!” I put some fresh gas in it and a fresh battery (it had been sitting in said shed for a good decade) and it started right up.) I drove it back home and started to work changing out almost every unseen part on the car. The car was producing copious amounts of white smoke on the freeway when I got off the gas. I pulled the head off and had it welded up and rebuilt and reinstalled it. The problem now is copious amounts of blue smoke when getting off the gas at higher revs. It’s acting as if the valve guides are leaking, but I just had all those replaced along with valves, seats, seals and so on.
could this be caused by the piston rings? I measured the cylinders and they were within tolerance. could it be a bad rebuild on my head? any thoughts on the matter would be appreciated before I go pulling the head off again.