Quote Originally Posted by mmandley View Post
10.1 refers to the compression ratio in the cylinder with relation to your cylinder heads. The higher the Compression the higher Octane fuel you need to keep it from per-detonation or pinging.

The 14.5 your referring to is the optimum fuel to air ratio which is 14.7-1 and this is whats needed so the engine doesn't run lean or rich.

This is one of the reason why gas engines have so many sensors on them to help keep this ratio exact all the time.

Diesels don't care, you run it rich it makes more power and dumps the rest as black smoke through the exhaust, Run it lean and it loses power, clear exhaust lol.

160+ is an idea compression per clinder, mind you this is a number I am pulling from memory and not exact. 175 is a really nice healthy engine.

A compression test is essentially testing the Valves sealing in the heads, and rings sealing on the cylinder walls, both are the main wear points in an engine.
If you see smoke <blue in color> at start up your Valve seals are going bad, this is allowing Oil to leak by into the cylinder and at startup you see blue smoke, White smoke is water in the engine and means a head gasket has failed.

I can go on and on, trust me LOL. Thats the basics of what is important in telling if an engine is tired or not.

Good thing is the Chevy Small Block 350 is called Bullet Proof for a reason, because they last and last. Idmar only stopped using them recently and switched to Ford because Chevy after more then 50 years is finally stopping production on them. The LSX series is the new engine Chevy is pushing. I personally would have rather seen the LSX engine adopted, so much easier to make gobs and gobs of power from those lol.
All things anyone with a boat should know IMHO. Great post! Except for the 'Chevy is awesome' stuff... Just Joshin.