Date: Sun, 21 Apr 2002 17:09:36 -0500
Reply-To: Stan Wilder <wilden1@JUNO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stan Wilder <wilden1@JUNO.COM>
Subject: Lifter tests ....... just a folly?
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Since I had a slow Sunday I pulled my spare 2000cc Air Cooled Type IV
engine out and started disassembly for the purpose of installing a
windage tray and other modifications.
I didn't get far before I got misdirected into investigating the action
of hydraulic lifters.
Taking the eight lifters out of the spare engine I set up a metal can
full of oil and carefully blead each one with a wire pin while it was
fully submerged in oil. (I disassembled an old, known to be bad lifter to
be sure that I could bleed them properly).
I then re-pumped each one with my little lever action press with the
lifters still submerged completely. (hand operated gear / rack, lever
operated press).
I had the eight lifters out of the good operating engine and each of them
pumped up to become solid columns with just a few pumps of the press.
I had counted on mounting a dial gauge on the head stock to measure
compression / drop of each lifter as pressure was applied.
All but one of the lifters became very solid and held the applied force
so I skipped the dial gauge setup.
The force being applied was equal to about 200 + pounds and seven of the
lifters showed no signs of compression after about one minute. The eighth
lifter developed about 3/32" drop after one minute but recovered after I
actuated a few pumps of the press. However it dropped again in about one
more minute of press action.
I set these aside and tested four of a eight set spare lifter set.
Only three of these four held pressure and became a solid column. The
lifter that did not hold its column height seemed destined for the trash
can since it quickly dropped as much as 1/4" on repeated testing.
What I learned.
If you've got a new lifter set they will most likely be good and could be
set with zero preloading.
If you're got an old lifter set they may perform better with a preload of
one to two turns of the adjusting screw.
If you're going to rebuild your own engine, you should probably test your
old lifters if you're going to use them again.
If the PO ran the engine with dirty oil the lifters could be past ever
holding a column.
Each full turn on the adjusters is approximately .050 inch (varies
slightly depending on the thread fit of the adjusters).
I didn't have a quality method to measure the exact pressures applied but
it would be interesting to see a more comprehensive test of time and
pressure.
Stan Wilder
83 Air Cooled Westfalia
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