Date:         Thu, 17 Jun 2010 16:33:37 -0700
Reply-To:     Roland <syncronicity1@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Roland <syncronicity1@GMAIL.COM>
Subject:      Last gasp: low compression exhaust valve can't pass smog
Content-Type: text/plain; charset=ISO-8859-1

Ok,

So, again trudged to the smog station after various lower cost attempts
(California).
-  High HC at idle, 270 PPM and more.  The max allowed is 120.
- HC at 2500 RPM is fine (because of course the compression happens at that
speed).

Apparent root cause:  exhaust valve, cylinder #4
- compression is in the 85 lb range, vs the others in the 130-145 lb range.
- leakdown test said "84% out of exhaust".
- I can see / feel/ hear an occasional miss at idle (I think).
- So it seems pretty clear that lower compression / miss will cause high HC.
- It runs fine, last weekend just did a 270 mile trip.
- Root cause of bad valve?  Don't really know, the engine has AMC heads,
vehicle has over 200K miles, so obviously the heads were redone at some
point.  About 4 years ago I blew the water pump on the freeway, didn't turn
it off right away, but also passed smog after that event.  Maybe just more
time caused the valve to go bad.  But I believe I've also read that the
valves in AMC head go bad faster than expected.   Also, the upper bolt is
missing from where the exhaust manifold / header attaches to #4, but I can't
feel any air/exhaust flow -- maybe the lower bolt is holding the gasket.

Potential paths:
- get the left side head replaced, not sure I am willing to do it myself,
tough to get at, seems like many peculiarities on this one,  I may screw
something up.  ( I would if I still had my Austin Healey).  The 2 shops I
spoke with would use a new head, from their estimates it must be many hours
of labor.
- go to the California Carb appeals to the referee.  I have the papework, I
think I've spent enough $ that they may give me a 1 time waiver.  (i.e.
delay facing the problem, but I am planning some trips, I don't want this
engine to go bad this summer.).
- get both heads replaced while we are at it?  (I don't have all the
records, but the bottom end probably has 200K + miles on it.)
- costs just go up from there.

Anybody have any ideas at all high I could get past the smog test without
replacing the head?

Thanks!
Roland