msx 150 compression

[MODRACER02]

hey guys anyone know how low the compression can be on the 150 before i should be looking at plating issues picked up the ski for 300.00

[ripcuda]

Wow... $300?! Nice. What was thought to be wrong with it to get it for that price?

Compression on the Weber engine is listed at 140 +/- 14psi @ sea level. So 125psi would be just out of service-manual-acceptable range... but would still run.

My MSX only got 110psi on both... so I decided to tear down and investigate possible Nikasil plating issues. Thankfully, I had none. Both cylinders look smooth and clean, so I'm putting in new piston/ring assemblies (rings not sold separately) with a light de-glazing hone.

I can't recall reading compression #s for plating failure cylinders, but I have to guess they would be really low... below any level of acceptable. That would be serious grooves and/or chips in the cylinder that the rings couldn't seal against. If you got or can borrow an inspection boroscope... that would be the best way to check. Pulling this engine is a PITA and you have to cut the cam chain to remove the head.

Cheers!

[MODRACER02]

Thanks for the info. got the ski cheap from and friend has a bad turbo plus i know the waste gate is stuck. The engine is out right now so i wanted to see if it was ok to try running like that before i put it back in. every thing else looks good no milky mess to deal with but it does have stock oil tank so im thinking of replacing that. I took inner cooler apart just to check all looks good so i think a bigger turbo and comp flash and we might be good WE will see thanks for the help any other things i should be looking for while i have the engine out THANKS AGAIN

[ripcuda]

Cool deal. You said you cleaned the IC out... but I would still pressure test the air and water sides to make sure there are no leaks. The other big trouble maker is the oil tank that leaks water into the oil. I just bought a new, updated Weber oil tank and rollover tank to avoid that issue. Also... I've heard the 2 MAP sensors are prone to failing if they ever get oil coated (oil ingestion) so if you have running issues... keep that in mind. I've heard of more than one ski (mine included) that had overheating issues due to the plastic water pump gear stripping. This requires pulling the engine to get to the water pump. If your ski didn't have any overheating issues... probably a non-issue. And once you get it all back together, be very careful about the oil level... too much oil and it's known to ingest it back through the intake fume breather hose.

Cheers!