multi grade oils

[B19]

Living in Alaska were temperatures range from -20F to 32F in the winter and 40F to 70F in the summer. I have been using Aero Shell 15-50W year round. I was wondering if I should change to a straight weight oil in summer. Currently I am changing #1 cylinder for low compression 53/80. Not sure if I have a burnt exhaust valve, cracked cylinder. Leakage is in exhaust. I preheat engine when temperatures get below 32F. Engine type is O320-150hp?


Any thoughts?


Happy flying.

[9 lives]

I use straight 80 all year 'round in my O-200, and it is very happy. It was very unhappy with either of two multi grades. My O-360 seems happy with Aeroshell 15-50, which is what it ran from overhaul, when I bought it, so I leave it for now. But It'd switch to straight grade were there the slightest problem.

Both engines/aircraft have oil pan preheaters and engine blankets.

[S-Works]

I have used multigrade in my Comtintal IO360KB for the past 1800hrs and it still runs sweet as a nut.

[Chilli Monster]

Same here - IO540, 1600 hours - 4 Atlantic Crossings and one Europe to South Africa and return. No problems at all

[ChickenHouse]

You should be able to find endless discussions on the issue in the internet ... My plane was running on TOTAL DM 15W50 all year long, but I was not happy with it - slightly higher oil consumption, a feeling of rougher run, guts feeling not well. I now fly summer D100 and when it is freezing cold 15W50 - feels better to me.

[A and C]

Multigrade

I have been running two Lycoming O-235's and two O-360's on Shell multigrade, the O-360 run just fine on it.

Both the O-253's have had problems with the Piston pin plugs being " bacon sliced" by big ridges that have appeared in the cylinder at the place that the rings stop at the bottom of the cylinder.

I am now running the O-235's on Shell 80+ or 100+ depending on the season, the problems have yet to reappear, it is a LITTLE EARLY to be conclusive about this but it seems that the O-235 MAY NOT like multigrade oil.

[B19]

Thanks for the input. The Aero Shell 15-50W seems to be doing a good job for me. I have had to replace 2 cylinders in the past 4 years for low compression, which is no fault of the oil. Just wanted to here what you folks think about straight weight oil.


Had to change both cylinders because of leakage in exhaust, the first was due to a crack in the cylinder. Still waiting for hangar space to change the current cylinder. Don't know if this one is due to exhaust valve or a crack like the previous cylinder.


Still hoping to fly by Jan 1 2015