Posted by Mike W. on April 02, 2004 at 00:04:45 from 205.188.116.214
In Reply to: Re: I'm not an expert, but I do know some posted by Daniel on April 01, 2004 at 22:55:46:
Again, I know the M30 better, but they are awfully similar.
I did bore out a 3.0/3.3 block, which shares the same 89MM bore to 92MM. And then I had the head off with only 20K on it, but only because I was putting it in a Motronic car and needed to change the cam which you can only do with the head off. The machinist that bored it out didn't want to do it at first and only did so on my insistance. He said it was pretty thin, but it was ok. When I had the head off, I could see where the head bolts had streched the bores into kind of a square, judging from the wear pattern. I can't say I liked it, but I now have over 100K on that engine so it can't be all that bad. And I take it up to 5500 regularly and occaisionly over 6 so it's not like I'm babying it. When I was juggling engines and took it out of my 80 E24 and put a stock rebuilt 3.3 in, it had dramatically less power, if it was missing anything due to the square bores it wasn't much.
So, after all that I can't say for sure, but I would strongly suspect that you can bore it 3MM over without problems, especially if you have others confirming it also.
Mike