Hi Folks,
Last week I mentioned my van could not pass emissions here in Utah
(Salt Lake City) even with a fairly new rebuild (<6K).  It was about 4
times over on Hydrocarbons.    I mentioned I had an auto mechanic
instructor friend with a smoker who was going to help me  try to
locate any vacuum leaks.  On Thursday I drove to his house.  I backed
into his driveway to allow easy access to the engine area from his
garage.

Immediately he called me to the tail pipe. He put a piece of cardboard
across the exhaust.  He then said he knew the problem. He said he
heard it while I was backing in.  Bad exhaust valve.  He based this on
the sounds and pulsing of the exhaust gases. It would puff when the
bad valve opened too soon. That was my big fear all along.

We proceeded to check the vacuum system anyway using the smoker. No
smoke came out anywhere so the vacuum system appears fine.  But now I
am trying to figure out the next step. The lowest compression was at
cylinder #2 at 95. The other three are at 105 to 115.  I am thinking
that #2 might be the culprit.

The engine was rebuilt in 2010 using new AMC heads. Now I am reading
how they aren't very reliable.  So I assume this is part of the
problem.  I'm wondering what other folks experience is using AMC
heads. I am guessing at this point its either a stretched valve or one
that isn't seating very well.  I guess it could also be a leak between
the head and cylinder if the head wasn't flat.  Any thoughts or
experience.

Anyone know if you might see the problem by removing the valve covers.
 It's not the news I wanted.
Thanks for any insight.
Ken Wyatt
82 aircooled westy
slc, UT