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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"I had hand-turned the prop for 30 revolutions once a
month to keep the parts lubricated."
I used to think this was a good idea and I'm not going to say it's a
_bad_ idea, however someone (perhaps Jeff) on the list pointed out many
years ago that unless the engine is turning at an RPM sufficient to get
the oil pump pumping, periodically turning the prop by hand doesn't bring
any oil up and onto the cam lobes and cylinder walls.
I've let my engine sit during this winter without engine movement for
reasons of laziness and some other distractions I've allowed. During
earlier non-flying periods I would periodically go over to the hangar and
run the engine until reaching operating temperature. This winter I
haven't been doing that. I'm on the verge of re-engaging with aviation
(biennial, medical renewal, aircraft annual) however so my plan before
turning the prop is to take my top plugs out and squirt some Marvel into
each cylinder and letting things soak for a day. I'll then slowly bring
the two pistons that were at top of cycle, down . . . and do some more
Marvel squirting and soaking. Also squirting some Marvel down the guides
each day. Following all that I'll run the engine to operating
temperature then drain the oil overnight - which I do anyway. Next day a
valve adjustment and some fresh oil. I'm not thinking I'd do a lot of
damage just by starting up the engine without any of this rigamarole . .
. however my thought is if there is a "better" way to do something,
especially with the engine, why not take the time to do it? Also, it's a
form of penance for being so lazy as to not get over to the hangar every
month and run the engine as I've always done during non-flying stretches
. . . until this recent period of inactivity.
All that aside, I just wanted to respond to Sid's post about turning the
engine over by hand once a month, thinking it was lubricating the engine.
It's probably good to turn the engine over by hand every month just to
keep everything from sitting in one position for months at a time, but I
don't think it's lubricating anything. In fact, it possibly could just
be scraping whatever oil is on the walls, off . . . thus perhaps doing
more harm than good. What do others think about this?
Mike
KSEE
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