Warming your Engine - part 2
Thread Starter
Joined: Jan 2003
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From: SX in SX in UK
Warming your Engine - part 2
Its that cold, damp time of year again, the time that starts in September and stretches through to May 
. Its the time when dripping aircraft are marooned on muddy fields and dampness and condensation prevades everywhere.
In the current issue of GASIL, ( we all read GASIL don't we?? )
Link to GASIL
on Page 5, there is an interesting paragraph:-
I was just wondering how many people actually turn the engine or warm it once a week? And if you do warm it, how hot do you run it - bottom of the green arc, centre of the arc or what? And how long do you run it for? Are frequent, short runs better or worse than infrequent long runs?
. Its the time when dripping aircraft are marooned on muddy fields and dampness and condensation prevades everywhere.In the current issue of GASIL, ( we all read GASIL don't we?? )
Link to GASIL
on Page 5, there is an interesting paragraph:-
During the winter, aircraft spend a considerable time either in a hangar or secured against weather dangers outside. Engine manufacturers recommend that engines which are not being used and run to normal operating temperature for a considerable period should be inhibited, and the LAMS schedule which forms the basis of most light aircraft maintenance requires the engine to be run every week or turned over by hand every fortnight if the aircraft is not being used.
I was just wondering how many people actually turn the engine or warm it once a week? And if you do warm it, how hot do you run it - bottom of the green arc, centre of the arc or what? And how long do you run it for? Are frequent, short runs better or worse than infrequent long runs?
Joined: Feb 2003
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From: The Front of Beyond
Kolibear,
I seem to remember reading somehwere (probably in an old flying mag) that if you do ground run the engine, you need to run it for quite some time (20 to 30 minutes) to make sure that the oil etc gets properly heated up and burns off any moisture and combustion residues such as nitrogen oxides. Failure to do so means that they can build up in the engine and cause all sorts of nasties to happen.
If I get a chance this weekend I may have a look and see if I can find it.
Brooklands
I seem to remember reading somehwere (probably in an old flying mag) that if you do ground run the engine, you need to run it for quite some time (20 to 30 minutes) to make sure that the oil etc gets properly heated up and burns off any moisture and combustion residues such as nitrogen oxides. Failure to do so means that they can build up in the engine and cause all sorts of nasties to happen.
If I get a chance this weekend I may have a look and see if I can find it.
Brooklands
Joined: Jun 2003
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From: EuroGA.org
One problem with these general aviation rags is that to fill the pages they print a lot of stuff which may apply to some type which was built in 1922, and another one last built in 1947, but the advice might be completely wrong for something else. Some of the stuff I've seen in these CAA-sponsored publications is pretty amazing.
Lycoming for example (can't find an online reference right now but have read it enough times) recommend against ground running because the engine doesn't get hot enough to burn off the moisture in the oil. And if not run for several months, they suggest doing specific things to preserve the engine.
I suppose one could ground run at a fair RPM for quite a while. But why not just fly it? The pilot needs the currency too, probably rather more than the plane. There are plenty of perfectly flyable days in the winter - just not at weekends
Lycoming for example (can't find an online reference right now but have read it enough times) recommend against ground running because the engine doesn't get hot enough to burn off the moisture in the oil. And if not run for several months, they suggest doing specific things to preserve the engine.
I suppose one could ground run at a fair RPM for quite a while. But why not just fly it? The pilot needs the currency too, probably rather more than the plane. There are plenty of perfectly flyable days in the winter - just not at weekends
Joined: Dec 2001
Aviation Qualifications: ATPL
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From: GA, USA
My 2 cents.....
GA engines ( at least the great majority) run very dirty at full rich mixture and low power settings.
Inherent to the design, although they are supposedly air-cooled that is not entirely true.
The internal cooling is done by the oil and additional cilinder head cooling is provided by an (overly) rich mixture.
So ground running could do more harm than good concerning combustion by products contaminating the oil quicker.
In order for the moisture to burn of the oil temp needs to be at least 180F/100C and if you take a careful look at the oil temp on a cool day you will not reach that temp after the runup but quite a while later after take-off.
I guess I would change the oil after a winter of ground runs.
Inherent to the design, although they are supposedly air-cooled that is not entirely true.
The internal cooling is done by the oil and additional cilinder head cooling is provided by an (overly) rich mixture.
So ground running could do more harm than good concerning combustion by products contaminating the oil quicker.
In order for the moisture to burn of the oil temp needs to be at least 180F/100C and if you take a careful look at the oil temp on a cool day you will not reach that temp after the runup but quite a while later after take-off.
I guess I would change the oil after a winter of ground runs.
Nexialist
Joined: Jul 2003
Posts: 182
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From: Milton Keynes
Not from an aviation background but automotive, oil is cheap, engines are expensive. I'd go with B2N2 and change the oil after and before the winter, it's not expensive. Blow by from a rich mixture will thin the oil quite rapidly.
Don't know if any regs apply, but if I was leaving an engine outside/in the cold for an extended period I would whip out the plugs and squirt in some oil, have a fresh oil filter and oil in it, consider using an old set of plugs in it instead of the new ones, keep new set at home and refit in the spring.(lets face it if your not using them all the plugs are doing is keeping out the water)
In the spring whip out the old plugs and spin it over a few times to expel oil etc. put in new plugs, then run it up to temp, then drain out oil and put nice new stuff in. Oil does a lot of weird things when left alone, nasty acids etc.
If you are only going to change the oil once, it's better to put the new stuff in in the autumn, then use it all summer, than leave in the stuff you've you've used all summer then leave it in the engine all winter. Don't leave old oil in an unused engine.
Don't know if any regs apply, but if I was leaving an engine outside/in the cold for an extended period I would whip out the plugs and squirt in some oil, have a fresh oil filter and oil in it, consider using an old set of plugs in it instead of the new ones, keep new set at home and refit in the spring.(lets face it if your not using them all the plugs are doing is keeping out the water)
In the spring whip out the old plugs and spin it over a few times to expel oil etc. put in new plugs, then run it up to temp, then drain out oil and put nice new stuff in. Oil does a lot of weird things when left alone, nasty acids etc.
If you are only going to change the oil once, it's better to put the new stuff in in the autumn, then use it all summer, than leave in the stuff you've you've used all summer then leave it in the engine all winter. Don't leave old oil in an unused engine.
Joined: Jan 1999
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From: north of barlu
As most of the aircraft in the UK are maintained according to LAMS the oil should be changed at the 50 hour/6 month check so the oil should never be more than six months old ( well seven months if you engineer grants you an extention ).........or am I missing something ?.
