^^^
It's your piston (1st or 4th).
you hit 25+psi boost and burned a hole in your piston



Do you have complete pinout of AU ECU?
That would be awesome!!! I think AU ECU should be same as KRD.

 

Detonation! Too early of a spark when your piston is traveling up and then kaaaabooommmm!!

 

to me , looks like a bullet.. well i mean the casket.

 

It's a hole in the top of No1 piston, caused by the spark plug. By the pics it seems to have something to do with the idler pulley bearing, but I don't know what

 

Some of you are really close on the location and the problem. The what caused the problem has yet to be stated though...

 

no 4 piston?

is it from something that came into the engine from outside?

 

It must be the No1 piston as it's the 1 at the front of the engine.

 

It's right in the center where the spark plug would be, and about the same size. It doesn't look like detonation. I've detonated a few pistons in my day and you normally see some sort of stress fractures or tearing. If something broke off in it, the odds of it hitting dead center like that are one in a million. My guess is the rod failed or a bearing failed, forcing the piston up in to the spark plug.

 

hmm... u melted bearings, which screwed up the timing, which screwed up ur cam , which closed ur intake valve when it was suppose to be open and your boost shoved ur valve right on top of the piston when it was moving up?? hahahha

 

Well, I'll end the debate.

You can see that all my valves and spark plugs are fine.


Yeah, it's the #1 Piston.
Yes, its a "hole" in the piston caused by detonation.

You can see in these photos, that carbon has almost completely filled in the hole


That let's you know how long ago the hole happened...

You can see a beter shot of the damage in the flash photo


That was detonation damage. It basically "melted" a section of the piston, but it's not quite in dead center (just a bit off center). The melted material was then litterally "torn" from the piston top by combustion/piston forces. The edges of the hole is where the piston was hot, but not hot enough to melt. It deformed and "tore" the material away. There's still a bit of rounded molten looking metal in the center of the depression. There's also a complete and total lack of cracking, letting you know it wasn't impact damage from above or below. The combination of no cracks/stress fractures, along with the molten/rounded metal left in the middle is the real clue that the problem is detonation.

let's hear 3 cheeers for Alpine Developments tuning!

The pulley bearing problem others identified is what happens when you over tighten that pulley bolt too much. It puts pressure on the pulley bearing and VIOLA, toasted pulley bearings and race.