I have to say I find it hard to believe that monograde oils are superior to multigrade oils in highly utilised engines.
It would surprise me too, but there is a lot of anecdotal data pointing to fewer problems, particularly with valves sticking. It could be anecdotal (like so much stuff in GA is complete nonsense) or there might be something in it.
There is a real lack of research; most forum posts are too brief, the highest-hour owners are not on forums, and there is a lot of equipment and mission profile variation.
The bottom line seems to be that any approved aviation oil will provide adequate protection for engines that run on a very regular basis.
Strong anecdotal evidence has surfaced that low usage engines will benefit from the use of can guard .
There seems to be little evidence to connect any particular oil with valve sticking ( type of valve guide , high operating temperature and engine cool down time seem to be more likely culprits ).
Personal opinions seem to abound especially based on single events.
Engine manufacturers recommendations regarding running temperature, time at temperature along with calendar oil changes seem to get ignored.
Blackstone labs once published data indicating different oil brands not particularly showing any advantage over the other. They have tremendous amoung of engine wear metals data so I believe their feedback is credible. The problem really is how frequent the engines are flown. The best thing an infrequent private pilot owner can do is to protect the engine during the times of disuse. I use camguard and try to regularly fly the aircraft even for 15-20 minutes to get the oil temperature high enough to get rid of vapor.
By9468840 wrote:
I use camguard and try to regularly fly the aircraft even for 15-20 minutes to get the oil temperature high enough to get rid of vapor.
I would add crankcase moisture control between flights unless frequent.
I was chatting to an FI the other day who works at a not very local school. They have moved there entire fleet (C152 and PA28-161’s) onto 100 hours between oil changes. They do have UL91 at their home base but are actually using 100LL as its cheaper.
A year or two ago I used to fly a PA28 that was on 75 hour oil changes and I have to say the oil looked pretty ropey come 75 hours.
I could go with 100 hour between oil changes on unleaeded fuel but I’m no so sure about when using leaded fuel. Has anyone ever ran and oil analysis when operated to 100 hours?
I do 25 hour oil changes, avoid starting engine unless I’m going to fly at least 1 tach hour, try to fly at least every 2 weeks, and change the oil filter at 50 hours. Presently just over 1/2 TBO.
These longer intervals may work for aircraft flying many hours almost every day, when the engine is limited to manufacturers TBO.
Most of our non-commercial aircraft go well over recommended TBO.
(But one was successfully landed last year after the engine seized, the crankshaft snapped and the composite propellor shredded, far beyond recommended TBO.)
Bathman wrote:
I could go with 100 hour between oil changes on unleaeded fuel but I’m no so sure about when using leaded fuel. Has anyone ever ran and oil analysis when operated to 100 hours?
Oil is so cheap relative to the rest of flying I don’t see a good reason to not change it frequently. I doubt I have ever hit my hour limit between changes, since I don’t fly that often. It’s usually the time limit. My analyses from Blackstone show good numbers – I run Phillips x/c 15w50 with Camguard and have an engine dryer.
If you don’t change the oil filter, it takes about 20 minutes start to finish to change the oil through the dipstick with an oil extractor. If you fly a lot and don’t need camguard, the cost of the oil is less than 100 euros, or 2 euro per hour if you change at 50 hours.
I have lots of oil analysis data – various threads – but nothing going anywhere near 100hrs.
I would expect the oil to be practically useless.
I’ve never gone past about 60. The oil consumption certainly goes up – see above link.
There is this which suggests some owners may be doing 100hr servicing, but I have never found an SR22 owner willing or able to confirm this.
