Peter you are correct but the vernatherm is unable to maintain oil temp when the OAT falls below about 10C on the ground, I am of the opinion that Cessna got the cooling optimised for a hot day in Texas, they do make a winterisation kit but this is clearly designed for a cold day in Alaska and is overy restrictive for the southern U.K. During most of the winter.
My next move is a cowling swop between one aircraft that always makes the correct oil temp and the cowling from an aircraft that has trouble making the oil temp, it may be the baffle rubber seals are in doing the job far too well.
OK; yes… a limited control range.
On the IO540 one usually has the opposite problem: running too warm. Hence I reworked my baffle seals and that brought the CHTs down some 20-30F.
How about blocking off a part of the oil cooler? That would give you the best control over the oil temp.
The oil cooler outlet is totally blanked in the winter and will be unblanked by the end of the month, with the C152 oil cooler hanging out in the breeze all the time it is always providing some cooling as there is always a small oil flow to prevent coring in very low temps.
OK; I meant not blocking the oil at all but just covering a part of the oil cooler with some foil.
Do you have CHT and oil temp gauges?
There is a long history to this issue. For example the Israeli Air Force (on one of whose TB20 engines I am flying right now) had two oil coolers factory installed. I saw a TB20 the other day which was ex IAF and they were simply connected in series, and unsurprisingly reports from the USA (where the whole ex IAF fleet ended up for sale) indicated that this was a waste of time because the CHTs ended up higher because now you had two big holes in the rear baffle through which the air would be escaping instead of being forced to go through the cylinder fins. It seems that on all these engines you are trading off cooling the oil, or cooling the cylinders (which in turn impacts the oil temp, obviously). Further evidence for this is that 1,3,5 run hotter than 2,4,6 because of the oil cooler hole behind them:
In the last article I found from M. Busch, Aeroshell doesn’t seem that bad..
Really not trying to justify the actual oil I am using, but try to get enough argument to justify an eventual change…
http://www.avweb.com/news/maint/182909-1.html
we recommend that you use a multi-weight oil such as Phillips 20W-50 or Aeroshell 15W-50. The Aeroshell semi-synthetic is a slightly better lubricant, while the Phillips X/C is slightly better at cleansing. Both are excellent choices.
Or maybe recommendation have changed since then ?
Busch has on several occasions been quite vocal against Aeroshell 15W50 because it is 50% synthetic and synthetic oils do not keep particles (combustion byproducts) in suspension so they end up as sludge. He prefers mineral oils, and even more so monograde, for engine corrosion protection.
http://www.flyingmag.com/aircraft/pistons/piston-engines-keeping-your-cylinders-happy
Busch, on the other hand, strongly opposes semi-synthetic oils. “The problem with Aeroshell 15W-50 is that it’s half synthetic oil, called polyalphaolefin (PAO), which works great in cars because they run on unleaded gas but is a disaster in airplanes because we use leaded avgas,” he said. Busch recommends using a good single-grade oil, such as Aeroshell W100. For operators in cold environments, which require a multigrade oil, Phillips 20W50 (which has no synthetics) is his choice.
And also the article that was quoted by Peter earlier;
I have investigated many cases of premature cam and lifter distress (generally caused by corrosion during periods of disuse) and without exception they all involved engines operating on Aeroshell 15W-50 multigrade.
You should watch this video.
What Mike Busch uses himself is Aeroshell W100 with Camguard. But keep in mind he lives in the San Diego area IIRC.
so they end up as sludge.
That was my experience with Exxon Elite, very much so, but not at all with Shell 15W50.
I think the reason this stuff goes round and round is simply because if you fly frequently, it makes little difference what engine oil you use. You could probably run an IO540 on 2-stroke lawnmower oil…. And if you don’t fly frequently, and park in the “wrong” environment, the engine will disintegrate as corrosion takes hold and trashes the camshaft, which trashes the tappets (or vice versa)…
The best thing for engine longevity is to fly every week, or every two weeks at most, and changing the oil well before 50hrs probably helps too because 50hr oil is just a black gunge.
This area is near-impossible to research properly because most GA owners fly far too infrequently, and most have not owned their plane from new so they cannot vouch for what the previous owner(s) did or didn’t do, and journey logbooks from previous lives are either unavailable or can’t be trusted. Every case I have come across of a premature engine “disintegration” involved this scenario i.e. nobody actually knew the whole-life usage pattern.
In your opinion, is there an increased risk of “engine event” when switching oil ?
I am considering Philips X/C 20W50 and Camguard, as replacement of AS15W50
I have never heard of such a thing. All the aviation oils in common use in Lycos can be mixed.
For information, and with agreement of the shop, Phillips 20W50 is imported in France by STRASBOURG AVIATION
Price for 12*1Qt is around 80€/TTC w/o shipping.
After pretty long discussion with them, they explained have been running with Phillips only for more than 3 years now, and find it excellent oil.
They prefer it over AS15W50, and definetely over Total 15W50.
They also use Camguard as additive.
PS: Strasbourg Aviation is a Cessna Service Center
