When I rebuilt my '81 Vanagon engine a couple of years ago, everyone told me
it would be really loud and smoky and not to worry about it - that it would
just need to run for about 15-20 minutes like it's about to explode, but I
should just stand there and not worry about it.

Well, despite this advice, I still thought something must have been wrong
when I started it for the first time - it sounded sooo bad, but I continued
to let it run.  Sure enough, after about 20 minutes, it had died down and
ran just great.  I "adjusted" the valves again the next day and 500 miles
later - but no adjustment was needed either time.

Unless you think you may have done something wrong, or think there's a
specific problem, I'd say let it run for a while.  Does it sound like it
gets any worse the longer you run it?

Good luck,
Ed Wilson

>What does an engine sound like and feel like when it's started up for the
>first time, with new pistons and cylinders and rebuilt heads? Does it feel
>tight? Sound kind of rough at first? I seem to have a bit of valve clatter,
>does this settle down with time (hydraulic valves) ? I let it run for a few
>minutes, but it seems to want to die and I'm afraid to let it run anymore.
>Do I need to just grit my teeth and bear with it for 20 minutes according
>to "How to rebuild your aircooled engine"?
>
>Is it just that the rings are a little tight and need to wear into the
>cylinders? And the valves need to wear in also? Any advice as to what to
>listen for, to do, and not to do when breaking an engine in for the first
>time would be GREATLY appreciated, I'd rather not make an expensive
>mistake!   Thanks  Tom