This summer I had an interesting conversation with Durward Balgrave from Texas. He operates a ranch and has a significant fleet of vehicles, from farm machinery to competitive tractor pullers.
Most of the fleet is used for a short time and then sits idle for the rest of the year. Even in the high humidity, he has let many of them sit for up to — and sometimes well over — a year without any rust or corrosion problems.
This summer he and his boys justified the purchase of a 2016 Cirrus SR22T for use in their operations. After the purchase, the seller gave him a list of do’s and don’ts for the aircraft — and he was shocked at the recommendations.
He was told to operate the engine long enough to bring up the temperature every week or two, change the oil every four months or 50 hours, pre-heat the engine when the ambient temperature is below freezing, manage the oil temperature to keep it in the 180°F range, plus a host of other suggestions.
He reached out to me to determine if all this was true and, if so, why?
Unfortunately, the answer is yes, it is true.
The why requires a longer answer.
Diesel and automotive oils have been upgraded many times in recent years to handle the increased demands of technology changes in engines.
Unfortunately, these changes cannot be applied to aircraft piston engine oils.
The two major problems are ash type detergents and ash type anti-wear additives.
Air-cooled aircraft engines need to burn some oil to help lubricate the cylinder walls, but with this oil consumption comes deposits when ash type detergents are burned in the combustion chamber. These deposits can lead to pre-ignition and cylinder damage, so they are not allowed.
I know that a lot of people call oils like Aeroshell Oil W a detergent oil, but it is not. It is an ashless dispersant or AD oil. There is a very significant difference between an AD oil and an ash type detergent oil.
A big difference is in the cleanliness but, more importantly, the basicity of the oil.
The basicity index is an indicator of the level of detergent and dispersant additives, as well as the capacity for neutralizing the acidic compounds that form during combustion.
The ash type detergents neutralize way more acids that form from sulfur, from unburnt fuel, and moisture that combine in the crankcase of an idle engine.
The second advantage with automotive and heavy-duty engine oils is zinc dithio phosphorus or ZDTP, an anti-wear additive. This additive coats and increases the wear protection for iron parts, like cam and lifters, significantly better than non ZDTP oils, but it also attacks softer metals like copper and silver.
Many aircraft engines have copper alloy exhaust valve guides and most radial engines have silver master rod bearings. That’s why ZDTP is not allowed in aircraft engine oils.
So, are aviation oils that bad?
No, the requirements of the engines are just that dated.
For example, the formulation for Aeroshell Oil W, not the multigrade or Plus oil, but the straight weight oils, have not changed since 1958. Think about that.
In more than 60 years there has been no significant change, even with all of the technical advances in lubricants. Just think back to 1958 and all of the changes that have been made since then in almost everything else we use.
Is the Lycoming recommended additive in the new Phillips oil the same as Cam-Guard?
Is there an advantage to using Cam-Guard over the oil that has the additive?
It is not CamGuard. It is Lyc recommended additive for some engines.
Yes, CamGuard offers more advantages than the Lyc additive, to include a seal conditioner, which is an advantage for engines with a long time since new or overhaul. Checkout the website and the independent testing done on it.
I think you meant to write “outdated engines” instead of outdated oils.
An oil change is cheap compared to an overhauled engine…
Ben this is so much BS, you never answered the question as you can’t. IE(this oil hasn’t changed in 60 YEARS) We all know that was the old oil ran in radial engines in WWII, but oil and additives has along with viscosity has changed.The problem is the owners change oil and let it sit for a year or more and they thinking that starting up the engine once or twice will protect it ,then beg the AI not to change it at annual time as it only has two or three hours on it . I see this as a marketing ploy to sell more oil(the date expired in the can so pour it out and buy new oil) Answer that,and who determines how old oil in the can needs to be replaced,HIMMMMM?.
To be fair with Ben, he could write a book on the subject, but in a small limited article he had to address oil so most pilots could understand it. Oil has changed in additives ,viscosity how ever to be brief go to the manufacture recommendation for each engine. IE(aviation diesel ,water cooled Cont.0-240 to name a few) Most aircraft engines were designed before 1958. Some additives are approved ,but some are not (the secret mystery oil) added to old radial engines 60 years ago. I have an unopened Qt.of 100 0/0 synthetic Av-oil that’s no longer made due to product Liability. Yes Mineral oil is old, but many oils are now for modern A/C engines. Again read your manufacture recommendation for your engine.
There is one change that comes to mind. CamGuard. I’ve been using it in my IO-520 with Phillips 20W-50 for 13 years. Oil analysis improved after it’s use. A great side benefit of CamGuard for older engines like mine is it’s seal conditioner additive.
I even run the HD Diesel version in my flat tappet Cummins. The new version, emission friendly diesel lubricating oils aren’t as flat tappet friendly as the older formulations. 370,000 miles and counting…
Manny,
I too use Camguard and Phillips 20-50 on my ‘little’ GO-300. When I first started using it I was surprised at all the carbon in the oil filter. The compressions all came up 5 psi or more….
Oil analysis shows excellent condition, all metals very low.
The engine is now 100s of hours past tbo and still meets all the TCM performance specs. for airworthiness.
My exact experience.
“Just think back to 1958 and…”
Anybody want a ride in my ’58 MGA?
Ben, Phillips released a new Product called Victory oil at Airventure 2019. It has an additive to help prevent the corrosion on the cam lobes. Can you comment on this oil? Thanks
Phillips 66® Victory Aviation Oil is an ashless dispersant, engine oil pre-blended with the proper concentration of antiscuff/antiwear additive (LW-16702) as mandated by Lycoming Service Bulletins 446E and 471B and Service Instruction 1409C. It is recommended for use in opposed piston and radial piston aircraft engines where cam lifter wear is a concern.
Ben,
Doesn’t the lead, TEL, in av gas limit what that is allowed in aviation oils.
I remember Shell trying a synthetic av oil and the TEL caused engine damage.