Premature Camshaft / Cam Follower failure

I thought you were trying to dispose of the X/C a while ago, because something was missing from it…

It doesn’t have the Lycoming friction modifier which I thought was important but I have changed my mind. It is not required for my engine (only for very few actually) and all the information I found suggests that it won’t do anything good on my engine.

Belgium, Germany, France etc..

In Belgium there is Loma Air but, though their website says they sell spares, they must be primarily a workshop which is perhaps not what you want.

Somewhere in this thread (I can’t find it now) I seem to remember somebody theorizing that newer Lycoming cams/lifters are made from inferior material. I don’t know what if any data they had to support that, but its interesting to see this Comanche and its O-540 for sale with apparently 1623 hrs since 1963, 51 years on the original engine build.

http://www.barnstormers.com/listing.php?id=941404

Mine (an O-320) now has a little under 1000 hrs since 1971 manufacture, unless the previous owner did an undocumented overhaul. No problems to date, runs great, doesn’t make metal. My theory on the cause was European wet weather and long winters, since that’s where the problems seem to occur. I wouldn’t be surprised either way.

I think there are many factors which make it damn hard to do any “research” in this area.

One is the weather – but the USA has plenty of coastline too and the sea has the same salt in it I would expect an engine in Arizona to last for ever if just sitting on the ground…

Another is that lots of oil filters are never cut open. I would guess 50% are never cut open. I have seen some spectacular cases of non-maintenance and sometimes this appears in accident reports (though it is rarely the direct cause – if it was, much of piston GA would be dead). So loads of engines are making metal but the owners don’t know.

When I had my TCAS system put in, the “everything-145” “highly respected” installer did some massive bodges, including potentially life threatening stuff (controls eventually cutting into wiring) but they would not have been discovered by any owner unless he/she looks under inspection covers and does a full and free controls check, which practically nobody does… so I am not surprised to hear the company has a great reputation.

BTW, another great data point to support my belief that “fly often” is not a major factor preventing Lycoming camshaft corrosion.

The German Pilot und Flugzeug operates 2 Grumman AA5 which they offer cheaply to its readers. The aircraft really fly a lot without any extended downtime. One of them had an engine overhaul and new camshaft only a few years ago by LOMA (i.e. very reputable shop) and recently suffered from a prop strike so the engine was opened. I believe it was 1500h in 3 years or so and the camshaft showed major corrosion and has to be replaced.

The “fly for one hour at least once per week” is as good advice as “light a candle and pray”.

You might be right but again other – unknown – factors come into play.

My 2001 engine was found to be heavily corroded when opened in 2008 – see the photos – for the crank swap.

Yet I fly once a week…

But if you look at the original French logbooks, the dates between engine shipping and installation are “ever so close” to the 365 day Lyco limit before the engine has to be overhauled to remain airworthy. A Gallic Shrug? What do you think? And I am far from the only TB20GT owner with those dates in the French logbooks. It is well known from those close the action that those engines were sitting on the shelf for a lot longer. In fact 14 of the 2000/2001 engines were still on the shelf in 2008. More info here (search for “logbook”).

So there is an explanation of “why frequent flying doesn’t prevent rust”. The engine was full of rust when installed!

How come I didn’t see this in oil analysis? I didn’t start doing that till 2005 by which time all rust in contact with moving parts would have come off.

How come nothing showed in the oil filter? Rust doesn’t end up in the oil filter. Only major secondary damage ends up there. And only really major stuff ends up in the strainer. Also, maintenance 2002-2009 was done by companies who did so much bad work that I cannot be at all sure if some or any of them opened up the oil filter. Only post-2009 can I be 100% sure of the maintenance.

Yet my engine was opened in 2002, when I had the prop strike. How come the rust was not seen then? Well…. the old-timers who know the company who did it, a “Lycoming distributor” called CSE, will understand They were completely capable of leaving the rust in there. In fact I spoke to a guy there, years later but before they went bust, who told me that Socata’s rust problem, and the way the logbook entries were done, was well known in the business. I was trying to milk him for some specific info so I didn’t ask him whether his employer would have put back together an engine with all that rust…

So, as I say, good research is hard to do in this area.

If somebody says they flew frequently, yet they got a rusted engine, there are plenty of explanations.

An expression from accountancy is: there is only cash, and everything else is conjecture. In aviation maintenance / operating history, there is only what you know for certain, and everything else is not really known, no matter what the seller or the logbooks say…

here

It is one hour (the 2nd half is a Q&A session) but I really recommend it to anybody who looks after an aircraft. It’s very well made – one of the best I have seen.

There is an interesting comparison of Lyco v. Conti engines and how they differ in the ability to detect large metal fragments.

At 22:00 it describes the exact issue I had, with air leaking in through a not properly closed alternate air door, causing a high silicon value and lots of extra wear.

Around 28:00 – this is Lyco guidance (Conti don’t publish any):

Very good – thanks for posting the link. I’m sure many of you on here already know about much of this but for me, having just acquired a homebuilt aicraft, and currently on a steep learning curve, it’s excellent stuff.

So, how many of you Lycoming drivers insist that your mechanic checks the suction screen for large pieces of metal? And if you operate a Continental, do you insist they filter the oil?

Congratulations on getting your plane back together!