My buddy blew the ring lands on his WRX. However I'm interested in that spot on top of the piston. Does that look like an injector could have gotten stuck open? Or is that a detonation mark?
Thats a little strange, the injector fires so far upstream that there shouldn't be a way for the injector to leave a mark like that.
That's what I thought. This is Bryce's car....he's talked to you guys about a SS1 but wants to know what happened. His car used to be a e85 car. Dunno if that matters but who knows. Both his driver side cylinders failed the compression test. Dunno if the other piston looks like that.
I think this was on a stock motor. And I agree with matt.....I doubt this was from a leaky or stuck injector since the fuel still has to hit the valve before it enters the combustion chamber.
But the pattern looks like it was spraying in that spot hard. Any chance it could be a plug issue like a spark plug too hot or something? Doubt it but I'm grasping here.
Theres the problem... the factory motors from 08+ run a much tighter ring gap. We have seen anywhere from .004-.008" on the top ring and about .014" on the second. Problem with that is some motors that run on the tighter side of the spectrum actually butt up the end of the rings causing this problem. On earlier motors the ring gap was much larger so you could get away with making higher power levels before this problem became an issue.
The clean spot on the piston is completely normal for a motor thats burning a ton of oil... the gas coming from the injector will clean a small portion of the piston. I have seen it plenty of times with motors we have pulled apart.