Fellow vanagon types

    The oil pressure relief bypass in most 2.0 air-cooled and in all WBX
engine feeds right back into the intake side of the oil pump so all the oil
is filtered that goes into the oil galleys and lifters. The early air-cooled
engine had both a bypass for the oil cooler and a pressure relief plunger
from 1970 on.
    I have a constant flow of used and used up engines flow threw my shop
and I see what build up is in the oil and crankcase. Sometimes I see metal
but mostly its byproducts of combustion varnish and sludge. In the days
before multi grade oils  paraffin build up was common but with the addition
of detergents to the modern multi grade oils paraffin no longer build up in
huge cakes of mud as it once did. It is very easy to see when an engine is
torn down if the oil was regularly changed by how clean the crankcase is. I
think that the varnish is more of a problem with lifter failure than metal
flake.
    I also strip lot of propane engine cores from Zambonis and they are as
clean as the day they where assembled with no discoloration (varnish) of the
crankcase thats quite a contrast to gas engines.
     The use of Marvel mystery oil is to dissolve the varnish and let the
check ball in the lifter seal so the lifter become ridged again.
    The fact that the vanagon lifters are on there side makes it much harder
for the air in the lifter to exit threw the push rod feed hole that is at
the half way point in the height of the lifter in its installed position. I
have seen positive results from backing off the adjusters and having
clearance long enough to let the lifters fill with oil and then 0 out the
lash or attempt preloading. I wrote the words in the Bentley book they call
it an editors note. they gave me two lines to come up with a way to say that
the lifters can cause problems that can lower compression when the engine
warms up and can lower intake manifold vacuum taking on the appearance of a
fuel injection related problems.
    I have countless emails from people that just want to thank me for
helping them sort out the poor running condition by backing off the lifters
to 006ths. This is a good diagnosis tool and a way to get lifters to fill up
and quiet down. Once the engine runs correctly then attempt preloading.
The engines I build have the adjusters set to 006ths when they leave my shop
because it had gotten to the point that I had to tell my customer to back
off the lifters to have a decent compression when the engine warms up. As
for the 2 turns I don't agree that you need 2 turns to properly adjust the
lifters any preloading is enough to let the lifter self adjust. The stock
rocker geometry becomes correct when the adjuster is turned in two turns.
On my engines I set the rocker arm geometry so that at 0 lash to 1/2 turns
has the correct rocker arm geometry. I do this for a couple of reason first
I use reground OEM cams they are harder than any replacement cam on the
market but the base circle is sometimes smaller in effect making the push
rod shorter. The second reason is I feel the lifter has a better chance to
pump out the air in the lifter if the inner lifter piston has longer stroke
as it compresses.

Going faster miles an hour with the radio on
 I remain

Bob Donalds
Boston Engine

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