I pulled the head, to find the piston on no.3 has a bits broken away from it. The head has metal scratches all over it and is slightly dented by the valves.

So.....now I need to replace the pistons and the head!!

Are the pistons easy to replace?

The cylinders look fine it is just the piston that is broken.

Since this was a forged piston that has just been ablitherated...should I stick with forged pistons or shall I go back to standard pistons and hope that it was just the bad fueling that has caused this?

Mad John can you hook me up with some forged 10:1 compression pistons from Korea?

 

guys take a closer look at the journal in the center of the pic..




ok this is why it blew.. its a mix of 3 thing

1. wrong ing timeing.. there for you were knocking thats why it melted then broke off
2. way to lean.
3. plugs you must run a heat range of 8~11.

you must do some head work. so look at my pic of my compression chamber on my head you must do this. this is why we do it here to remove the knocking you must remove the upper and lower tabs in the CC.. if you do what i did you will not knock even on pump gas.. but how you program you ecu is the key




i am running 1.5~2.0 bar of boost on the same pistions..

and after looking closer at your pistons it was just a matter of time before the other 3 went too.. that discoloration is not gas but piston burn..

you need to get the following if you dont want to do this again

1. a plx-550 lamba
2. bigger injector. FPR and 255 intank pump.

 

Hey mad john, can you explain the coloration of your head and the circles on the valves?

 

^^+1..please explain MJ

mad john I think you are right with all three, a combination of crap tuning, a crap spark plug and the wrong timing has lead to this situation.

Can you get me some stock pistons?

 

Part of my job is photography and I do photoshop for hours every day...the color saturation needs to be turned down for the head to look normal in that shot.

He has said previously that those valves are polished to a very high shine (2000 grit? )

There was a reddish color temperature on the lights used for that photo, and the lines on the valves are a reflection of something else and lighting artifacts.

That's my guess, anyhow.

 

^its the reflection off of the roofing beams

 

Oh, ok. The way it's pictured, the head looks like it's been fried at HIGH temperatures and the metal has been eaten by the mad power and/or lean conditons generated by your engine. But now that I know it's a polished head and the colors are reflections, I know that it is in great condition.