There is also the fact that the oil pump is at one end of
the engine and the cam shaft lobe that fails is probably at
the other [a guess] and the oil takes some time to reach the
journal and establish a full oil bearing.

Add a little sludge, maybe some cold oil and an over-revved
engine, and you get cam lobe /journal failure or the lifter.

Pilot error due to poor operation.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"George Patterson" wrote in message
news:J11wf.517$sa4.41@trnddc07...
| Jay Honeck wrote:
|
| Does anyone *really* know what causes a camshaft to fail
like this? I read
| about it happening with alarming regularity, and it's
never attributed to
| anything in particular.
|
| In the absence of some catastrophe, such as a bent
pushrod, this is generally
| caused by not flying enough. The layer of hardened steel
on a camshaft is fairly
| thin. Let the plane sit long enough, and rust will form.
When the engine starts
| again, the rust is worn away, making the thin layer of
hardened steel thinner.
| The worst wear points, of course, are the tips of the
lobes. Once the hardened
| steel wears through, the softer steel underneath goes
pretty rapidly.
|
| "So why not build the shaft entirely of hardened steel?",
I hear you cry. That's
| because the harder steel is, the more brittle it becomes.
The best strength
| comes from this sort of lamination of hard and soft
steels.
|
| George Patterson
| Coffee is only a way of stealing time that should by
rights belong to
| your slightly older self.