which oil 0-300 D 1580 hrs

[new2cessna]

I have a 48 170 with a 0-300 D and need to settle on best oil to use. Engine is running fine I'm in Chas sc and it is HOT! Looking at logs I see 20-50 Phillips , aeroshell 100,in pa. I read engine designed for 40 wt. and 50 wt. made it run 20 degrees warmer assume Fahrenheit. I'm going by Dilmar to pick up a case as my fbo charges $9.75 a qt. and I use a qt every so often, not bad. at first it was leaking. that is fixed, but I dont yet know actual burn rate. Thank you all for info on door springs. Bruce's warnings and photos made me take my time and it was accomplished with no problems.The co-pilot door had not been repaired before and repair was quick. Once I saw how the inner door handle retaining spring works it was straight forward, with help of Bruce's pics of course. Thank you and Happy flying!
PS: The glare shield works great and perfect area for temporary auxiliary led panel lights. Can see instruments. Tim

[pdb]

This is a much discussed thread so I will try to abbreviate... There are some good discussions here if you search around.

The answer is .... it depends. And it depends somewhat on how often you fly and how long you fly when you do.

In some uses, the biggest threat comes from internal corrosion during periods of inactivity. The worst case scenario is faced by engines that make a lot of short hops and aren’t flown regularly. Combustion produces water vapor and it gets in the oil, mixes with combustion products and becomes somewhat acidic, especially when it’s cooler. This can turn oil into milky sludge. Engines need to be flown frequently long enough and hot enough to boil off the water vapor. How long is long enough... IDK but the literature suggests that you need at least an hour at full operating temperature. Longer is likely better.

For those who don’t fly much (perhaps 50 to 150 hours per year), the bigger threat our engines face is internal corrosion, rust, rather from wear in use. The good single weight oils like Shell seem to stick on the inner parts of the engine longer and provide greater protection from rust. Use the cheaper single grade oil and change your oil often to get rid of those combustion byproducts that are not driven off by more use. Change oil every 25 hours or six months, which ever comes sooner.

The multi viscosity oils seem to provide better protection in use for operators who use their planes more. The risk they face more is wearing the engines out through use and the multi viscosity oils seem to provide superior anti-friction protection, especially during start up at lower temperatures. The better flow (lower viscosity) at low temperatures however means that the oil flows off the internal parts more readily. So the trade off is better lubrication in operation but somewhat lower protection from rust during periods of inactivity. Multi viscosity oil like Phillips 20W50 is probably a better choice for engines that are flown more frequently.

[pdb]

The other thing to consider is whether to think about regular oil analysis at oil change. At 1,580 hours, your engine is approaching the end of life. Sometimes when engines get old, rings get worn, they just burn more oil, leak more, and produce less power but do not present the threat of catastrophic failure. There is no need to worry excessively about high time. Just continue to fly and start stockpiling parts for the eventual overhaul. You may get hundreds of additional hours of use.

At other times, if bearings start to fail, you are facing a different situation.

Oil analysis when done regularly, can help you spot the trends in engine wear and indicate when you can continue to operate in old age safely and when you need to start worrying.

[new2cessna]

Pete, thank you for info and insights. Much appreciated! Tim

[Joe Moilanen]

I've used nothing but Aeroshell 100 and got 2550 hrs. out of the last run. Re-builder said that the lower end looked great when he rebuilt it. My crank has 4300 hrs. on it since new and was still within factory new tolerances. I fly at least every two weeks year round, always preheat in the winter and change oil every 25 hrs. even though I have an F&M filter. I never run it over 800 rpm for at least 10 minutes when I start it and let it warm up good before take off. Could just be lucky but it has worked well for me.

Joe

[mit]

which CAR Chevy or Ford?

[Joe Moilanen]

which CAR Chevy or Ford?

Chevy...

[cessna170bdriver]

which CAR Chevy or Ford?

Chevy...

Honda.

[GAHorn]

..... I read engine designed for 40 wt. and 50 wt. made it run 20 degrees warmer assume Fahrenheit. .....Tim

That is an incorrect interpretation. The SAE 50 wt allows the engine oil temp red line limit to be increased to 240 F (compared to the 225 F limit previously.). The increase is only allowed if straight 50 is used, not multi-grade according to the engine TCDS.