Date: Thu, 29 Aug 2002 20:38:37 -0500
Reply-To: tmarciniak@WI.RR.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tim Marciniak <tmarciniak@WI.RR.COM>
Subject: Losing valve lash just after adjustment-why?
Content-Type: text/plain; charset="us-ascii" ; format="flowed"
Just did a compression test and two cylinders were low @ 100 and 106.
Heads done about 20,000 miles ago by a VW mechanic (not dealer). Van
has ran pretty well since them but lately I have developed a lumpy
idle and low manifold vacuum (10-12). I researched everything I
could find on the age old valve lifter issue including a call to Bob
at Boston Engine were I purchased my heads from. Followed his
instructions and adjusted the valves to .006 inch valve lash. I
adjusted both intake and exhaust when engine cold. Just to be really
thorough I rechecked them almost immediately after I adjusted them
(did not rotate the crank yet) and I swear I was back to zero
clearance so I readjusted again but did not recheck again cause i
wanted to finish and the mosquitos were really bad last nite. I also
checked all the valves for clearance before I adjusted and I could
not get a .006 inch feeler gauge in on any of them--I am suspected my
mechanic may of installed these heads the old way (preloading) and I
am starting to see problems now. My question is why did I lose this
.006 inch clearance just moments after I made the adjustment?
I did start the engine up after adjusting all the valves and it ran
pretty much the same, initially the manifold vacuum was about 14 but
then dropped to 11-12 after the engine warmed up and idle was lumpy.
Could it be the lifters are doing something strange? I am running
20W-50 for the summer.
Tim
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