To some degree, I have to agree with Achima, in that it seems that it’s a bit of a crap shoot …
Point in case: I sold a Twin Comanche that had fairly high hours on the engines and much worse, sat outside, near the cold & damp English Channel for 4.5 years. I was totally up-front about it to the buyer. I spoke with him a year later and he told me they pulled the engines apart and both cams and all followers were fine !
Go figure.
Guys, please correct me if wrong, but as I said above, things like preheating, slow warming and cooling of the engine should not have any effect on the longevity of the camshaft. It’s the “top end” that you can help by doing so, but we are talking the “bottom end” here!
So while the operator can, the pilot can not do much, through his “engine management technique”, to either help or
harm the camshaft.
It’s a waste of time to think about it too much … treat the engine right, change the oil regularly and if you want preheat it below 0 C (i started doing that) and use Camguard (i do). The rest is pure luck.
Contrary to Achim i am sure that long periods of inactivity are bad for airplane engines. FWIW
you can make any Lyco engine eat its camshaft, and thereafter most of the remaining internals, if you let it get corroded through a lack of use.
I think there is enough evidence that even flying very frequently can destroy a Lyco camshaft. I don’t believe in the “fly often” mantra. It does not directly affect the camshaft longevity. In fact, the vast majority of GA aircraft fly very seldomly and there loads of them with 20 years on the same camshaft and without any obvious issues. You can’t visually inspect it easily but you can look at the oil filter and measure the lifter travel (required annually for all D-reg aircraft beyond engine TBO).
In my opinion it’s monkeys forging camshafts. Some of them last, others are crap. The ones produced on Mondays are probably worst.
As I think I wrote earlier, you can make any Lyco engine eat its camshaft, and thereafter most of the remaining internals, if you let it get corroded through a lack of use. It doesn’t matter what oil is in there.
The puzzling thing is that sometimes this doesn’t happen, and nobody knows why.
However the problem with statistics is that while collecting selective data is easy (e.g. post on a pilot forum and ask how many have had such and such) both the pro- and against- data requires a lot of legwork and in practice few people bother. One sees this in so much of GA, starting with e.g. CAS bust stats where they analyse the actions of pilots who busted CAS (and were later traced) but nobody analyses the actions of pilots who didn’t bust CAS.
So a lot of cases where “nothing was found” can be explained simply by the fact that nobody looked! Most pilots don’t do oil analysis, many maintenance companies never cut open the oil filter, etc and in any case most owners don’t ever own a plane for long enough for any problem to show up, so even if a correlation was obvious it would never be spotted because the cause and effect are separated by years.
I think this does suggest the oil was responsible
Not relevant statistically, I also know of engines that ate their camshaft running on Phillips X/C and being flown fairly regularly.
>>>> A long time ago, I used to use Total. I stopped after I “ate” a camshaft on a Lycoming IO-360 despite that it was being flown fairly regularly.
I think this does suggest the oil was responsible
I don’t think anybody suggested it will damage your engine, but if it contains less of some ingredient that may explain why it is a bit cheaper.
It’s ridiculous to think that Total oil could be responsible for engine damage. It has the same specification and you could just as well believe in homeopathy if you say that.
I use D100 + Camguard and i am pretty sure there’s not much more that can be done oil-wise
Cessna factory, then ferry flight.
I had Bathman’s one in mind.
But the thing is the rotax 912 at a microlight school not to far from us
That’s a different engine. Doesn’t the Rotax have the crankcase vented into the inlet manifold, like cars have? Also a Rotax doesn’t have that cam interface weak spot which is the classic “trash a Lycoming” starting point.
Which I assume was equally abused did 3600 hours
Sadly I don’t think one can assume that. There are very particular patterns to certain kinds of renters in certain situations. To say more would open me to accusations of over-generalising 
but I have seen all kinds of crazy stuff of flying once a week for the last 15 years. I know of one school with a (nice) Rotax aircraft and sure as hell they would not be renting that one to the same people who they would rent a C152 to.
I am doing the Annual tomorrow on the TB20… 50% Shell W80, 50% Shell 15W50, Camguard
The cost of the oil barely features in operating costs, on any plane, IMHO.
