wrote in message
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Bill McKee wrote:
Head. Gasket or valve.

"nate" wrote in message
. ..
I have a 8 cylinder 350 (I think GM..it's in a boat)

Engine back fires and sputters. Engine does not leak oil that I know
of.
(or at least not very much)Compression test revealed 0 compression in 1
cylinder and all others were ok. Based off these symptoms, Is it
likely
that I will have to do work on the engine block or will the problem be
likely in the Head (gaskets or other)


Why? It could very well be a hole burnt in a piston, or a valve broke
off and pounded a hole in the piston. Usually if it's the head gasket,
you'll show a little compression, but will leak down easily. Same with
a burnt exhaust valve.


When the valve breaks off there is not a little hole in the piston.
Normally the piston splits and the rod breaks. And the cylinder can crack
also. Makes a little tapping sound before a single big bang sound. Been
there, done that. Pistons rarely have a hole burned through them, unless
you are running really hard and lean. Then you see aluminum on the
sparkplug when you pull the plug. And depending on the size of the head
gasket hole, and the speed of the engine turning, you get so little
compression, it will not register on the gauge. Takes a couple of PSI to
move the gauge. You have to overcome the Schrader valve spring in the
tester. Same for a burned valve. And if the rocker for the intake is
broken, you also get a zero to very low reading on the compression gauge.