Possible though unlikely the cam is broken. If a fracture is at the
required angle the driven portion of the cam could have turned a few degrees
until the fracture angle caused the fracture to gra and begin turning the
other portion of the cam.

Although the gear is pinned and pressed fit to the camshaft, if the engine
had a hydrostatic lock when cranked (pretty likely??) the gear could have
spun a few degrees on the shaft. A simple visual inspection in the engine
space may not have revealed the problem.

It's probably time to pull the engine for a proper inspection.

Is the mechanic a certified CAT mechanic employed by a dealer or an
independent?

Good luck.

Butch

More likely, IMO, is that the cam gear turned on the cam
"JK" wrote in message
...
OK Guys,
I have a Wellcraft Sportbridge with twin 3208 Cat's sitting at my dock
with a Sick Port engine.
Went to fire it up, there was some instant clatter & then nothing. Would
spin but not fire.
Had a Cat mechanic check it out. He pulled the valve covers & then the
heads & found 6 bent valves along with some bent pushrods & one blown
lifter.
He checked the crank & cam timing (indexing) & said all was perfect.
Well, after a new set of heads etc, turning the engine over (by hand
now) the valves Still hit !
Cat mech said he is stumped as to the cause as the Cats timing is Gear
drive & the Cam Gear is Pinned & Press fit to the Cam & he's never seen
one move.
His thinking was that maybe water "had got in" & seized the valves to
the valve guides. He knows better now!

Prior history...this boat went down during
hurricane "Charlie" (snip -long story) However, the Port engine never
went under & had No Trace of water in it anywheres but was Pickled as a
precaution anyway.

The Starboard engine (that went under) is fine. Both engines ran fine
prior to Charlie.
Any clues as to what may have failed ?
Anybody here see this before ?
It's impossible to disassemble the front of this engine while it's in
the boat ;-(

TIA---Joe in SW FL