Vanagon EuroVan
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (February 2000, week 1)Back to main VANAGON pageJoin or leave VANAGON (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Tue, 1 Feb 2000 13:01:31 -0500
Reply-To:     David Beierl <dbeierl@IBM.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@IBM.NET>
Subject:      Re: Hydraulic valve lifter (mis)operation
Content-Type: text/plain; charset="us-ascii"; format=flowed

There's a distinction to be made here -- I've been trying to make it but apparently not clearly enough. The specified and proper and normal and correct and standard and usual procedure is to start with fully extended lifters (which is how they are when you install them), adjust them to touching and then two full turns beyond, secure them, and forget about them until the next rebuild.

UNFORTUNATELY that doesn't always work. There is a defect in the system (in some cases) that is allowing the lifters (in some cases) to overextend by a tiny amount which makes the valves leak. THIS IS NOT NORMAL OPERATION, BUT IT EXISTS. When it DOES exist, the "temporary" workaround cure has been to reduce the preload adjustment from two turns to one turn, or half a turn, or a quarter turn, or none at all. In the case of the engine that I'm driving around, it is absolutely intolerant of any preload. When I adjust by the method of backing off until the compression stops rising, I end up with about .006 lash.

I am trying to discover the source of the problem. I have theories about it, not yet tested. I invite ANYONE to discover and PROVE the source of this problem so that we can all go back to adjusting these things the proper way, which is two turns preload immediately upon installation. That gives the proper distance so that the lifter can compensate properly in either direction. There should be no need whatsoever to let the lifters "pump up" since they are installed fully extended and already full of oil.

ANY PERCEIVED NECESSITY TO REDUCE THE PRELOAD FROM TWO TURNS IS WARNING THAT THE PROBLEM EXISTS -- REDUCING THE PRELOAD (WHICH REDUCES THE SPRING TENSION IN THE LIFTER AT THE SAME TIME THAT IT REDUCES THE AVAILABLE ADJUSTMENT RANGE) IS A **WORKAROUND** AND NOT A CURE.

<flame off>

david

At 07:03 AM 2/1/2000 -0800, Richard Bias wrote: >All, > The whole thing about adjusting to 6 mils of lash was and is only a >momentary (1/2 hour tops I believe) part of the "adjusting process". No one >said (and if they did, they were wrong) to leave the valves at 6 mils of >lash. It is just to get the lifters to pump full of oil before you adjust >them back down 1 turn (360 degrees) from 6 mils, to allow the "hydraulic" >part of "hydraulic lifters" to take over from there. > Rich

David Beierl - Providence, RI http://pws.prserv.net/synergy/Vanagon/ '84 Westy "Dutiful Passage" '85 GL "Poor Relation"


Back to: Top of message | Previous page | Main VANAGON page

Please note - During the past 17 years of operation, several gigabytes of Vanagon mail messages have been archived. Searching the entire collection will take up to five minutes to complete. Please be patient!


Return to the archives @ gerry.vanagon.com


The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.

Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.