I seem to be plagued by this and usually around the 1200 hour mark. Now there are various stories on things that you should do to reduce it but they aren’t always practical. The engines fly about 600 hours a year.
The aircraft operate largely at about 55% power. Probably once every 50 hours they may get flown at full power for 20 minutes on there way to maintenance.
Every now and again the aircraft will get leaned aggressively on the ground and in the air. Say once every 10 hours.
Oil wise they run on total D80 most of the year. With D100 for some of the summer months.
Fuel wise it’s 100LL and there is nothing else available at our home base.
Cylinder wise they are superior. I read that ECI came out with exhaust valves that rotated and in doing so eliminated sticking valves. Does anyone have any experience of these?
I read that ECI came out with exhaust valves that rotated and in doing so eliminated sticking valves
ALL valves rotate, so nothing special about that, and unfortunately this does nothing to keep from getting carbon or lead build-up on the guides.
That said, I would think that these engines see 100 Hp @ every take off and go-around ?
You might try using a different oil, maybe even a semi-synthetique ?
The problem with this you won’t know if it’s having in effect until a year from now …
My maintenance organisation has moved all it’s maintained fleet to Aeroshell oils after a period using Total products which showed an increase in these sorts of problems.I have followed their advice and changed lubricant brand especially as I have just had my engine overhauled.!
Which Total oil did they use and which Aeroshell oil did they use afterwards?
I read that ECI came out with exhaust valves that rotated and in doing so eliminated sticking valves.
Valve rotation serves to protect valve against damage by eliminating hotspots, but not much else. It’s a very typical design feature of marine diesels.
Most Lycoming and TCM engines employ a “rotator cap” mounted at the tip of the exhaust valve stem that causes the exhaust valve to rotate. Intake valves do not have that feature as they run much cooler.
Re aircraft engine valve sticking and deposits around the guides, I can’t comment in relation to the Continental O-200, but FWIW last month I decided to take a look at the valves and guides on my Lycoming O-320 using the ‘rope trick’ and a bore scope. The engine is mid time, has never been overhauled since manufacture in ~1971 and does not have the updated guide material introduced in the late 1990s. What we found was basically nothing, no heavy buildup around the guides, all valves sliding with no resistance. This engine was operated on unleaded Auto Fuel for a period. I suppose that may have helped.
I have owned a light aircraft since 1988 and always used Aeroshell products because my maintenance organisation stocked it.A few years ago Aeroshell stopped dealing direct with many customers insisting they purchased through a very limited number of wholesalers.I had been mainly using Aeroshell 15/50 and straight 80 if required.When my maintainer changed their lubricant supplier to Total not being willing to buy through a wholesaler I went across quite happily to their multi grade product(preferring to buy a European product).My engine was around 1600 hrs total time ,high calendar but with recent factory cylinders around 200 hours total time.I over the two years only suffered one stuck valve on a cylinder and that required remedial work from an engine overhaul shop on the comparatively young factory cylinder.However my maintainer decided that their own large and diverse fleet was suffering significantly more engine problems compared to previous experience and have moved back to Aeroshell.For convenience reasons I have done the same.I have always noticed a big difference in the thickness of the two multi grade products when pouring though they have the same viscosity rating.I have just spent £21k having my 0-360 fully overhauled following camshaft failure into its second life cycle from new and obviously keen to protect my investment as much as possible.My past usage of approximately only 100 hours per annum leads me only to expect about 900 hours from cylinders before a shop visit or cylinder replacement is required In answer your question Peter I used both companies multi grade product but I believe the maintainer normally run their fleet on the detergent monograde offerings of the two suppliers..Regards Stampe
The reason I asked is that my info, from a US oil expert, is that Total is re-badged oil made by Aeroshell.
What I don’t know is whether the composition is identical.
With the cost of oil being somewhere south of irrelevant on the scale of flying costs, I would not use anything but a known quantity.
Well Peter there is no doubt in my mind that the 15/50 multigrade offerings of the companies have very different consistencies.Re the original post I believe with the continental O-200 and O-300 engines it is very difficult to get cylinders beyond 900 hours before a shop visit or replacement.Given the low power operation stated I am not surprised these cylinders are having problems I think they need to be worked much harder!I operated two O-200 engines for nearly 30 years good engines but not without issues 1800 hours TBO very unlikely without a lot of work.Rather blows a business model out of the water.Regards Stampe