Cessna 150 oil viscosities

[dmspilot]

I'm finding a lot of conflicting advice when it comes to proper oil grades.

The Cessna 150 POH specifies SAE40 (e.g. Aeroshell W80) with ambient temperatures above 40°F. Yet, many owners I've talked to are using Aeroshell W100 which is SAE50. Further confusion comes from the fact that the Continental operator's manual for the O-200 recommends SAE50 above 40° — thus the engine and airframe manufacturer are giving conflicting advice. Below 40°, both recommend SAE30.

My main concern is preventing corrosion during periods of disuse. The engine is old and the aircraft only flies maybe 3-4 times/month. Yet obviously I also want to avoid friction damage during startup in cold weather; I don't have access to preheat, although it is rarely below freezing here in the daytime. How much damage does it do to start it with W100 in it below 40 degrees?

I'm thinking that Phillips 20W-50 with Camguard might be a better option so that I don't have to worry about matching the viscosity to the ambient temperature especially seeing as to how the weather can be bipolar around here—in the middle of January it could be 70 degrees or 20 degrees outside. Or does it really not matter unless we're talking about 0°F versus 100°F?

 

[SoCal RV Flyer]

I think Phillips X/C 20W-50 w/ Camguard would be the perfect solution for your temperature range. If you fly it four times a month (and get the temp up to 180 degrees indicated for more than a half hour each time) I wouldn't be worried about corrosion issues.

 

[kgruber]

The airframe manual trumps the engine manual.

 

[Tom-D]

NEVER EVER put Cam Guard into a 0-200 key start engine. unless you really like failing starter clutches, and never run AEROSHELL 15W50.
Run Phillips 20W50 year around.

 

[Tom-D]

The airframe manual trumps the engine manual.

Gotta reference for that?

 

[James331]

My plane will sit for a while too, 20w50 with camguard works great for me, I'm also in a area which can spread from 0f to 80f, so 20w50 is a great year round oil.

 

[dmspilot]

NEVER EVER put Cam Guard into a 0-200 key start engine. unless you really like failing starter clutches, and never run AEROSHELL 15W50.
Run Phillips 20W50 year around.

Do you have a reference for that...and besides, wouldn't a starter clutch replacement be preferable to a rusted engine?

Aeroshell 15W50 is already off the table based on what I've read.

 

[kgruber]

Gotta reference for that?

As always....

""""""- NOTICE - Teledyne Continental Motors (TCM) engine operating instructions are generated prior to and independently of the aircraft operating instructions established by the airframe manufacturer. TeM's operating instructions are developed using factory controlled parameters that are not necessarily the same as those specifications required to satisfy a specific aircraft I engine installation. Because of this difference the aircraft operator should use the airframe manufacturer's operating instructions found in the Pilots Operating Handbook (POH) while operating the aircraft unless otherwise specified by the original airframe manufacturer.

http://www.tcmlink.com/pdf2/maintenancemanuals/x30041/x30041.pdf

 

[Dan Thomas]

Do you have a reference for that...and besides, wouldn't a starter clutch replacement be preferable to a rusted engine?

Aeroshell 15W50 is already off the table based on what I've read.

Aeroshell 15W50 has an anti-scuff additive in it to protect the camshaft, and it's the same sort of stuff that you find in Camguard.

The problem Tom points out is a valid one. That anti-scuff additive is really slippery stuff, and the clutch in the starter drive relies solely on friction to work. The additive interferes with it and will cause it to start slipping much sooner than it would under normal wear. Been there with that.

Some of the old guys here will remember the limited-slip differentials in some vehicles that would slip and act up with more modern oils. The fancy additives weren't the best thing for them.

 

[dmspilot]

NEVER EVER put Cam Guard into a 0-200 key start engine. unless you really like failing starter clutches

Aeroshell 15W50 has an anti-scuff additive in it to protect the camshaft, and it's the same sort of stuff that you find in Camguard.

The problem Tom points out is a valid one. That anti-scuff additive is really slippery stuff, and the clutch in the starter drive relies solely on friction to work. The additive interferes with it and will cause it to start slipping much sooner than it would under normal wear. Been there with that.

The below article from Cessna Owner seems to disagree:

Now, let’s circle back to address the one negative remark I mentioned early on—that CamGuard might “make Continental starter adapters slip.” The Continental starter adapter continues to be an ongoing maintenance issue being discussed in hangars and aviation shops around the world. In fact, Continental has addressed these concerns with two major engineering changes.

When wear takes place in the adapter, it becomes susceptible to slippage and sensitive to the frictional characteristics of the oil. This is why CamGuard does not contain friction modifiers. The main cause of wear in the two older style adapters turned out to be the inability of the adapter spring(s) to release because of starter motor resistance. If the motor does not turn backwards a small amount after engine start and release of the spring mechanism, wear will take place in the adapter. Before putting the starter on the adapter, perform this simple test: Grab the shaft of the starter with your thumb and finger. If you can turn it both ways, you’re good to go.

The CamGuard guys are a talented and curious bunch and have undertaken an effort to characterize the three adapter styles in various stages of wear with every oil and additive available. Initial results indicate that CamGuard may improve a worn starter adapter’s performance.

And from CamGuard's manufacturer:

Q: Will CamGuard Aviation affect my Continental starter adapter or clutches in other engines?

A: There are no friction modifiers in CamGuard Aviation. This is intentional because of the friction fit Continental starter adapters and internal clutches used by Rotax and Merlin engines. A slipping starter adapter is a sign of wear on the internal components of the adapter. By preventing the wear of these components, CamGuard Aviation will prolong the life of Continental starter adapters.

 

[Tom-D]

Do you have a reference for that...and besides, wouldn't a starter clutch replacement be preferable to a rusted engine?

the 0-200 isn't known as an engine that rusts internally. it won't help the cylinder bores and it will cause the starter clutch to fail,

 

[Dan Thomas]

The below article from Cessna Owner seems to disagree:


And from CamGuard's manufacturer:

Continental, in those instances, is talking about the starter adapter used on their larger engines: 470, 520, 550. Totally different system, where the contact area is much larger than that in the C85/90/O-200 clutch. The terminology differentiates the two systems: "adapter" vs. "clutch."

No friction modifiers in Camguard? What, then, are they talking about here? From http://www.aslcamguard.com/index.php/products/aviation
...we read, among other things, this: CamGuard Aviation contains advanced anti-wear additives to dramatically reduce the wear of cams, lifters, cylinders, rings, gears and valve guides.

I thought anti-wear additives reduced the friction that caused wear.

 

[Tom-D]

Continental, in those instances, is talking about the starter adapter used on their larger engines: 470, 520, 550. Totally different system, where the contact area is much larger than that in the C85/90/O-200 clutch. The terminology differentiates the two systems: "adapter" vs. "clutch."

No friction modifiers in Camguard? What, then, are they talking about here? From http://www.aslcamguard.com/index.php/products/aviation
...we read, among other things, this: CamGuard Aviation contains advanced anti-wear additives to dramatically reduce the wear of cams, lifters, cylinders, rings, gears and valve guides.

I thought anti-wear additives reduced the friction that caused wear.

Anti wear additives are often just adding the chemicals to get the oil to cling to parts on start.
TSP is a chemical that is often used as a antiwar additive, it's a polishing agent. and very bad for adaptors and clutches.

 

[Stewartb]

If I was the OP I'd try the Phillips with Camguard. If the clutch slips change to Phillips without Camguard. My bet is you won't need to change.

 

[mtuomi]

My C150M seems very happy with 5qt of Phillips 20W-50. I fly it 50-60 hours a month so I'm not very concerned about corrosion. It uses 1qt per 25 hours, so I only have to add 1qt per oil change cycle.

 

[tinerj]

Phillips 20W-50 year around.