Technically, Andy is right, you shouldn't do it.

I do know guys who do it anyway, and have no problems. Doesn't mean you won't have a problem though. Of course, it doesn't mean you will have a problem either.

Do a search on these forums, you'll find this topic comes up a lot, with lots of guys arguing both sides.

If it was me, I wouldn't do it. Not worth risking that much money in airplane, engine, etc when it's easy and not expensive to do it "right", at least for most of us.