has anyone used synthetic oil yet and what are your opinions
thanks
lenny

Lenny,

I have been using a semi-synthetic, Exxon Elite 20W50, since the summer of 2002. When I bought the plane the previous owner was using Phillips XC and when I changed the oil I usually had a little water in the oil. I started using the Elite and rarely have that problem now.

I have a remote filter and change the oil every 30 hours or 4 months and do an oil analysis at every oil change. The engine has about 2516 total time and about 500 hours since last major, the oil analysis' are still coming back with all values still well in the normal range.

Everyone will have their own preferences on which brand or weights to use, I have maintained a lot of rental airplanes that used a straight weight of brand "S" and they seemed to have a problem with oil coking up the rings to the point that they would not expand on the pistons.

If the engine has quite a few hours on it since last major, you might want to stay with what you are using until next overhaul. The synthetics or semi-synthetics might show leaks where straight oils don't. Like switching a 100,000 mile auto engine to a full synthetic!!!

Rick, thanks for the thoughts, mine is a o360 with 2150 hrs and no overhaul yet..no leaks, runs very strong, oil analysis are always really good, no indications at all..no metal in my screens. I fly usually every week, change every 25 hrs. I am using aeroshell 100 plus which seems to be what the engine likes the most.
I was told that the synthectics were a better oil to use but I just don't know anyone who uses it.
thanks again it help.
lenny

Synthetics vs straight oils has been a controversy ever since synthetics came into being. There is nothing wrong with them, and in fact may be better than straight oils in most circumstances. Number one, the synthetics are higher priced than straights, so practically all the mechanics think they are saving customer's money by using straights - reduces the bill a little bit. Number two, the old wives tales about synthetics are strictly urban legends - if they weren't good the manufacturers would have been sued out of existence by now. Number three, if you don't fly a whole lot, the synthetics are better for an idle engine because they stick to the moving parts longer - therefore they inhibit moisture and rust. The brand and viscosity are a matter of choice. I like aeorshell 15W50, but I'm going to switch to Phillips 20W50, because it's cheaper, and I doubt it has any less quality. Aeroshell's brand just commands a premuim price. If you fly 25 hours a month, then the straights will work fine, especially during summer. If you fly less than that you probably should consider a synthetic.

uote name='Bobby Young' date='Oct 7 2009, 04:14 PM' post='4210']
Synthetics vs straight oils has been a controversy ever since synthetics came into being. There is nothing wrong with them, and in fact may be better than straight oils in most circumstances. Number one, the synthetics are higher priced than straights, so practically all the mechanics think they are saving customer's money by using straights - reduces the bill a little bit. Number two, the old wives tales about synthetics are strictly urban legends - if they weren't good the manufacturers would have been sued out of existence by now. Number three, if you don't fly a whole lot, the synthetics are better for an idle engine because they stick to the moving parts longer - therefore they inhibit moisture and rust. The brand and viscosity are a matter of choice. I like aeorshell 15W50, but I'm going to switch to Phillips 20W50, because it's cheaper, and I doubt it has any less quality. Aeroshell's brand just commands a premuim price. If you fly 25 hours a month, then the straights will work fine, especially during summer. If you fly less than that you probably should consider a synthetic.
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Thanks Bobby...I guess I will just stick with the aeroshell plus until I overhaul. thanks to all for the replies...