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rob willison

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I have a 350 mercruiser inboard engine with about 950 hours on it. How can you be sure if you have a bad piston ring? How does it affet the engines over all prefrormence?
 
'Repair suggestions are more effective if we start with the symptoms and the engine's recent history, not the proposed repair. But to answer your question: remove head(s) inspect bores, remove suspect piston, inspect....and "negatively"
 
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rob willison said:
I have a 350 mercruiser inboard engine with about 950 hours on it.
1...... How can you be sure if you have a bad piston ring?
2...... How does it affet the engines over all prefrormence?
Click to expand...

1..... You would perform both a Cylinder Pressure test (aka compression test) and a Cylinder Leak Down Test.
These tests will give you an idea as to where the failure is occurring (i.e., head gasket, valves and/or piston rings).

2..... It would depend on the severity of the piston ring wear, and how much any wear has affected the cylinder's ability to create cylinder pressure.




,
 
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And then there's that told mechanic's standby--shoot a bunch of oil into the cylinder and try again. The compression numbers should shoot up if the rings area at fault. (If not, the valves are leaking.)

Jeff
 
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