Run it for a while before re-adjusting the valves. Just long enough to get it warm, but not hot. This will allow the lifters to pump up a little and make adjusting easier (more defined zero-lash point). 20-50 oil does not flow very well unless it is really warm outside. The fact that the clearance is being lost tells me the lifters are continuing to pump up further. Probably a good sign! Jay
Tim Marciniak <tmarciniak@WI.RR.COM>@gerry.vanagon.com> on 08/29/2002 09:38:37 PM Please respond to tmarciniak@WI.RR.COM Sent by: Vanagon Mailing List <vanagon@gerry.vanagon.com>
To: vanagon@GERRY.VANAGON.COM cc: Subject: Losing valve lash just after adjustment-why?
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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