>Do aircraft engines use high detergent, multigrade oil like cars do?
>
>The difference between draining hot or cold is the difference between
>getting
>99% of the old oil out vs 99.44%. If I was running a Jiffy Lub I'd want
>the
>oil drained when hot. Time is money, after all. But for those of us who
>change our own oil we can plan alternate chores whilst the oil is draining.
Dave:
You're really taxing my poor old damaged brain, but I will have to either
reply from memory or dig through my tubs of books and paperwork to find the
Lycoming and Continental Service Bulletins. I don't have the energy to dig
so here goes:
I just tried the Lycoming website and didn't see a button to click on for a
complete list of Service Bulletins. I did watch their video on Oil Specs. No
mention of hot or cold draining.
Anyway, I think that the SB just says to drain oil hot without explaining
why. I seem to recall that detergent oil is not approved for use in aircraft
engines (see brain-damage disclaimer statement above, however). Mineral oil
is recommended for the break-in period (except for turbocharged engines,
which are broken-in with ashless-dispersant oil) and ashless-dispersant oil
thereafter. I do remember that several multi-grade oils are approved as well
as several single-grade oils, depending on the ambient temperature. Thanks
for not saying multi-viscosity.
I don't think that Lycoming cares how long it takes for oil to drain, so I
don't think that quicker draining is the reason for the statement in the SB.
But I can't say what the reason is either. I'd be interested in finding out
what the reason is. Could just be CYA.
When I was performing 100-hr inspections, I would run the engine up and do
the required performance checks, put the 'plane in the hangar, remove the
cowling and start the oil draining right away. While the oil was draining, I
would remove one spark plug from each cylinder and do the compression test.
Talk about burnt fingers! Ouch. This is because the compression check was
supposed to be done on a hot engine. There; another open can of worms.
>And the beer tastes better without the burnt fingers.
I generally try to remove all burnt fingers from my beer before drinking, so
I wouldn't know.
John
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