Evo 3 Pistons

[petbeemer]

Pictured here are a set of Evo 3 pistons which are known to break ringlands.
This is a set of 4 pistons from the same engine,if you look close you will see carbon deposits all around where the rings sit but there is also a clean bit,where the clean bit starts and finishes is where the ringlands have cracked, this usually happens on the thrust face of the piston and generally makes the piston useless.
For some reason when Mitsubishi made the Evo3 they decided to up the compression from 8.5-1 to 9.0-1 probably to help with power off boost and to get the engine to spool the turbo quicker,in re-designing the pistons they also made changes to ringlands making the edges sharper and the gaps tighter causing 'ring flutter' which in turn causes ringland breakdown.
Symtoms are hard to spot as compression is rarely affected nor is oil consumption and generally the engine will run fine until more power is needed,but if your planning on rebuilding your Evo3 motor then budget for a set of pistons

[Karl3]

8) 8) thread pete.

[coltmanuk]

excellent info there mate.

[BigEars]

So I don't need to do anything about this right now? I don't intend on racing, or even running it really hard, it was just a bit of a show off car really. So do I need to get this checked out as soon as possible or can I just let her lie for now?

[Callaghan]

generally the engine will run fine until more power is needed,but if your planning on rebuilding your Evo3 motor then budget for a set of pistons

That's an excellent bit of info. Thank you for sharing this with us. My biggest crime is I like to accelerate from stand still a little faster than is completely necessary. Is that something that would warrant replacements.

[Ma986]

From what Petbeemer has said, it sounds like the deliberate revving you have been doing, may be a cause for concern, you should at least check it regularly. The fact that it is in giving that power boost that the ringland breakdown, I think it should be checked regularly.