Best oil to use in Continental IO550

[PhredPhantom]

I just got my Ovation 2 about a month ago and yesterday I finally needed to add a quart of oil.  I didn't have the logbooks with me to see which oil was used when the annual was done just before the sale but there was a quart of Aeroshell 20W50 in a ziploc bag in the baggage area so I assumed that was what had been used.  Since I was at an airport where oil was available for sale, I decided to buy a quart and keep the one in the baggage area as a spare.  The only 20W50 that the FBO had was Phillips but a local pilot there told me that Phillips was better oil anyway since it is not paraffin-based like he said that Aeroshell is.  He said that Aeroshell will eventually leave a paraffin residue in the crevices and corners of the inside of the engine and prop.  He also said that most of the folks at their airport, especially the homebuilders, use Phillips.  He also said that he had heard of some engine rebuilding shops recommending the change to Phillips after doing oil analysis samples for some folks.  I decided to put the Phillips oil in.  

 

So, after that long introduction, here's the question:  I've always used Aeroshell during all of my civilian flying career with Cessnas and Mooneys but now I wonder if  should think about going to Phillips.  What's the better choice?  What's the general thought of you more recently-experienced guys than me?

[jetdriven]

You can use what you like, except for Aeroshell 15W50. Its 50% synthetic which can cause the starter adapter to slip.

[PTK]

You can use what you like, except for Aeroshell 15W50. Its 50% synthetic which can cause the starter adapter to slip.

 

Is this documented in the literature?

 

Could it be that the starter clutch is going bad to begin with? 

 

Aeroshell 15W50 is an excellent oil.

[BorealOne]

I'm a Phillips guy.

[jetdriven]

Is this documented in the literature?

 

Could it be that the starter clutch is going bad to begin with? 

 

Aeroshell 15W50 is an excellent oil.

This topic has been beaten to death on Beechtalk. Quite a few pilots over there have switched to 15W50 and had their starter adapter begin slipping after that. Switching back sometimes it went away. To answer your question, the starter adapters are a highly loaded part that once placed in service, is technically goon bad from regular use.

[BigTex]

This forum has run this topic into the ground as well. To the OP, check out the Mike Busch webinar "All About Oil." Mike goes into great detail why he specifically tells his clients to not use Aeroshell 15w50. Watch the webinar and draw your own conclusions.

[MooneyMitch]

Just as a reference point, my former IO-550G6B was 2400 hours prior to overhaul, using Aeroshell 15W50 continually [and run LOP as well].  I see nothing in the engine logs regarding starter adapter replacment or slipping.

 

Incidentally, the technicians at PowerMaster engines told me they can always tell immediately upon teardown, whether an engine was operated LOP.  Much cleaner and much less carbon build up, of which mine was.  I'm not trying to start anything here, just passing along my experience.

[Danb]

Mike Busch was nice enough to respond to my inquiry regarding oil and in fact was against the Shell multi, that being said I still use it. I've had three Mooneys continuous since 1988 and have yet to have a bad oil analysis or replaced a jug, or had any top work done. I fully respect Mr Busch but based on my factual history I'm having a hard time taking his recommendation except that I have switched to Camguard vs the so called snake oil I've also previously used. I also now utilize an engine dehumidifier since my correspondence with Mr Busch. A class guy.

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[PhredPhantom]

Thanks for the responses to my questions.  

 

Some people mentioned that this subject had been done to death but I did a quick search in this forum before I started the topic and was a little surprised when it turned up nothing - maybe I didn't use the correct search words.  

 

Nobody addressed (at least in this thread) the question of whether Aeroshell is paraffin-based or not and whether that would make any difference in the first place if it is.

[rocketman]

I think it might have to do with the ability for Phillips to stick to the metal parts longer than synthetic or semi synthetic oils. I remember this argument sometime ago when ExxonElite was debated with Phillips XC. 

 

In any event, there is no right answer since we will all disagree. Nor is there probably any convincing real studies touting the benefits of one oil over another, sans the oil manufacturing companies themselves. 

[Guest]

RAM Aircraft of Texas, with vast experience overhauling more big bore TCM engines than most other places discourages use of synthetic and semi- synthetic oils based on service history. Check out their Operation and service tips, then oil recommendations.

Clarence