Date: Wed, 27 Jun 2007 21:49:34 -0600
Reply-To: vanagonvw <vanagonvw@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: vanagonvw <vanagonvw@GMAIL.COM>
Subject: Hydraulic Lifter Adjustments
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
81, air cooled. Hydraulic lifters
Damn, it is really hot here in Northern Utah... Sweating like a madman
in the garage, and under the van.
I am thinking this topic gets bandied about almost as much as tires :-)
I have read the archives, and other forums. Still want to better
understand some things tho....
How I got here may not matter at this point, but I am doing a leak test
on my 81 air cooled. The motor is cold. Last driven a few days
ago...Having a horrible time getting exact TDC. Off by a few degrees,
and the air pressure just pushes the piston down, and the motor around,
in whichever direction. :-)
To get started, I took the easy way, and went with number one. Used the
timing marks, and only needed a few tries to get the piston to stay up,
and do the test. It failed, with 90psi in, and about 50psi reading, or
45% leakage. In order to see what was going on with the valves, I took
off the cover, and noted that with the piston certainly at TDC, the
intake valve had a small amount of 'play' or 'lash' between the rocker
arm, and the stem.... The exhaust valve, however was leaking a lot,
based on what was coming out the tailpipe, relative to the intake, and
it had no play or lash at the stem. So, I backed the adjuster screw out,
eventually two full turns, resulting in a small amount of play, and
apparently this allowed the valve to close completely, and the leakage
went down to just 20%, which is not all that bad for an engine with 200K
miles on it. I would take that if they were all at 20%.
What did I learn, and how come I am supposed to set zero lash, at TDC,
and then one to two turns down, depending on which article I read? I
don't understand the notion of adjusting that rocker arm, so that it
actually opens the valve at a point when it is supposed to be
closed..... When the lifter pumps up, won't that make it even worse? Is
that indicative of a bad lifter? Weak springs? Wrong interpretation of
the procedure <g>
I would really like to understand how to set it up properly.
(section two)
It may be a totally moot point however, as number two, after an hour of
trying to find TDC that would not push the piston down, I found almost a
50% leakage, mostly exhaust if I am any judge, and both valves had a
small amout of clearance. They were not open at all, based on the
ability to pull the rocker arm back off the stem, on both of them. Not a
lot, but enough to know, I have a problem....
My only choice is to get the remaining cyls tested, adjust the valves as
best as I can, and park the van, indefinitely, but I need it as a spare
set of wheels. My Ford Taurus trans went out today, so without the Van,
I have nothing to drive, and I at least need something in case of an
emergency for my kids, or hell, even me :-) No intention of driving it,
unless I absolutely have to, as that could make things ugly if its a
seat that has dropped a bit, but I cannot afford a new trans for the
Ford, let alone a new set of heads for the van, so I want to set the
valves up as best as I can. Plus, good practice, in case I ever get to
be able to fix this.
Anyway, I hope things maybe look somewhere in the future, but for now,
I want to do the best I can with what I have, so any education from the
resident experts, would be appreciated. Kind of two issues here, but I
want to learn what it is, that I am seeing on both cylinders...
Thanks very much,
John
P.S. Would I want to try and take that head off, with the engine still
in the car, and more important, if yes, is it an overwhelming bitch to
do? Probably another thread, once I get it all tested, and adjusted as
best I can....
| 
