Mike Stirewalt wrote:
> .....would someone like Langford or Jeff or anyone who knows
> their VW Type 1 please straighten up this question for the sake of anyone
> wondering how best to maintain the engine during periods of flying
> inactivity?
Mark Langford
m...@n56ml.com
http://www.n56ml.com
I wouldn't swear that the VW cam is submerged in oil, and given that the
engine only holds something like 2.7 quarts of oil, and I'm not sure how
much or even if the lowest lobes are in the oil when the engine is
stopped and level. The oil pump intake from the sump is about 1.5" from
the bottom of the sump, so it's getting oil at the the lower part of the
pump, at least.
Next time I'm at the airport I'll check a VW case against the marks on
the dipstick to see where the oil level normally is. I do have a
cutaway drawing from a 1969 VW Beetle manual that gives me the
impression that the cam is probably not even partially submerged in oil,
so turning the engine over isn't going to help lube the lobes....just
the bearing shells....for whatever that's worth.
I was telling somebody else today though that it's not oil draining from
the bearings or anywhere else that worries me....it's the cylinder walls
rusting, especially in a humid outside environment like an airplane
lives in. Valve guides don't worry me at all...they are barely lubed at
all, and are not going to corrode like the steel cylinders will. The
rest of the engine can probably sit for 50 years without a problem,
assuming the cam is submerged. At least one or two cylinders will be
open to the atmosphere though, through an open intake or exhaust valve,
and they will develop condensate and rust. About all you can do for
them is spray something like Corrosion-X (or some other brew that's made
specifically for the purpose) directly into the cylinder and hope for
vapor protection. Moving the crank a few degrees will keep the rings
from sticking, but that's not a big issue either. I guess if you wanted
to be fanatical about cylinders, you'd pull the rocker shafts off to
close all the valves, and fill the cylinders with oil. I were going to
"pickle" one for thirty years, that's what I'd do, and add enough oil to
the crankcase to submerge the cam. Unfortunately, we don't usually plan
to neglect an engine....it just happens.
As for the oil pump, it's worth noting for taildraggers flying behind VW
engines that after a total rebuild, it takes forever to get the oil pump
primed and oil flowing in the engine, because the pump is up out of the
oil, and it's not very good at sucking air! I've learned to set the
tail under a saw horse to get the nose down and crank the engine over
with no plugs in it until I get oil pressure, and sometimes I've also
had to fill the dang pump with oil from above (through the oil pressure
sensor port) to make it happen.
--
Mark Langford
m...@n56ml.com
http://www.n56ml.com
*************************************
When I purchased my assembled 2180 VW from Great Plains many years ago,
Steve Bennett recommended that I turn the crank 30 revolutions each month
that the engine was not being run. Before I installed the engine I had a
nyla-flow tube on the top oil gallery in place of the oil cooler
connection.
After 3 revolutions I could see large bubbles coming through the tube,
then
progressively smaller bubbles as I continued hand cranking. Some engines
spray oil on the bottom of the pistons for cooling. The VW does not do
that
spay system. All bearing parts on the VW get positive lubrication from
the
oil gallery with exception of the piston rings and valve guides; these
parts
get either splashed from the crank or dribbles from the wrist pins for
the
rings and dribbles from the rocker arm tappets on the valves.
Was Steve Bennett providing me the correct recommendation?
For what it may be worth, I understand that so-called aircraft engines
have
the cam shaft above the crank, and thus do not lay in the crank case oil
pool when the engine is not running. VW engines have the cam shaft below
the crank and lay in the crank case oil pool when the engine is not
running.
The VW oil pump gears are always immersed in the oil in the crank case.
Sid Wood
Tri-gear KR-2 N6242
California, MD, USA
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