What caused this piston to melt?

[85glhomni]

I recently bought a 1985 omni glh. The guy I bought it from told me it was bored 20 over. I started it up and it smoked like crazy. To make a long story short, I took the head off and there was a hole in the number 1 piston. I took the piston out of the block and the hole went all the way down the side melting the piston. The pistons were cast. what could of caused this to happen? bad injector? lemon piston?

[lametec]

I did that once. Bad injector was my problem.

[turbovanman]

LEAN baby!!!!!!!!
or a bad case of preignition but 99% too lean!

Got pics?????? :big grin:

[lametec]

Here's a couple pics of my melted piston:



and



18psi on an intercooled 2.5. Engine only had 10k miles since a total rebuild.

O2 gauge was showing pig rich (two extra injectors were on). Apparently main injector #1 wasn't up to the task.

[turbovanman]

Wow, some serious meltage, da*n!!