Todd Carrico wrote:

Let me quote John  Schwaner on page 83 of the  Sky Ranch Engineering Manual;
"Each time the rocker arm tries to open a stuck valve you risk catastrophic
engine damage." snip. "Tremendous valve train forces develop as the camshaft
lobe tries to force the valve open. When operating normally the highest
loaded
surfaces in the engine are the cam shaft lobes and additional loading may
induce failure." snip. "A damaged camshaft lobe requires complete engine
removal and disassembly."

Piston engines. sheeesh.  You can have them :-)

Paul Lamar

Todd Carrico:
FWIW, Superior tried to make Lifters for the Lycoming a few times.  Finaly
gave up.  They could never get the metalurgy right.  Seems that thier is
some real magic to making the faces just right.  The last effort, they sent
a bonded, independant engineer to evaluate both processes.  He concluded
that we were not going in the right direction.  He could not tell us how
they did it, but confessed that it looked more like art than science.  The
look in his eyes was all I needed to tell that they were doing some tricky
things to get a lifter to survive at all.  Any engineering that is this
finiky in its execution has got to be replaced IMHO.  Roller lifters are
better, but no lifters is the best!

tc

The lifters in a Lyc O-540 are 1939 Cadilac hydraulic lifter designs.

Paul Lamar
 
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