Super Jet Superjet piston failure
- Thread starter aj91799
- Start date
- Location
- Texas
Looks like Water intrusion or Lack of Oil on bofth Pistons. The blow-by came later after the Rings seized.
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I’ve religiously mixed at least 50-1 amsoil on this ski, but have only owned it for about 5-10 hours ride time. You’re saying when the rings seized it allowed air blowing by the piston rings until it blew?
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- Location
- Texas
If the Pre-Mix had the right amount of Oil, then either Water washed away the Oil lubricating/coating the Pistons or the Carbs settings were lean or there's an Air Leak somewhere.
Once the Rings seized or stuck flush inside the Ring Groove, the Cylinder lost compression, because the Rings can't seal if the Ring edge is not flush against the Cylinder Wall.
The Rings need to be able to "float" and spring in and out of the Grooves to seal and accommodate the Piston Travel. With too little or no Oil, then Metal to Metal friction will happen. The Metal particles will clog the Ring Grooves causing the Rings to stick.
When the Rings seize, they don't seal, then hot Exhaust leaks by, hence blow-by.
Once the Rings seized or stuck flush inside the Ring Groove, the Cylinder lost compression, because the Rings can't seal if the Ring edge is not flush against the Cylinder Wall.
The Rings need to be able to "float" and spring in and out of the Grooves to seal and accommodate the Piston Travel. With too little or no Oil, then Metal to Metal friction will happen. The Metal particles will clog the Ring Grooves causing the Rings to stick.
When the Rings seize, they don't seal, then hot Exhaust leaks by, hence blow-by.
DylanS
Gorilla Smasher
- Location
- Lebanon Pa
Seeing as how this is a single carb engine and your front cylinder ate it first I’d start with ruling out an air leak first and foremost.
It probably got hot and your ring(s) caught the exhaust port.
Pics of the top and bottom of the piston would help with diagnosis.
Pistons look new?
What arrestor were you running and what do you think you were doing when it let go?
Insufficient chamfer could also be something to keep in mind.
It probably got hot and your ring(s) caught the exhaust port.
Pics of the top and bottom of the piston would help with diagnosis.
Pistons look new?
What arrestor were you running and what do you think you were doing when it let go?
Insufficient chamfer could also be something to keep in mind.
Myself
manic mechanic
- Location
- Twin Lakes AR
Let's see some good pics of the piston tops and the head domes.
- Location
- New Jersey
Subscribed! trying to track down a similar issue
- Location
- Detroit
Looks to me like some ring butt happened then hammered the groove. There seems to be a few issues going on.
- Location
- Charlotte, NC
Never tear a blown engine down before first doing a leak down to check for air leaks. It can eliminate a lot of future questions as to what could've caused the engine to fail. Once it's torn down there's no way to know if you had a leak somewhere