pulled head off, found big problems

[98ls1ttop]

well i finally got the head off to my 92gsx 6bolt. found all valves are bent. also some material melted to the cylinder wall. looks like melted metal. and the piston is melted right where that metal is. i'll take pics later and post them. looks like the piston melted to the side of the wall somehow. time for a rebuild!!!

ps. i just bought this car, had 0 compression, knew it needed rebuilt. just would like to know what the deal is and how it scorched the piston

 

[91 Turbo Mitsu]

Its called detonation. Could have come from to much boost and not enough fuel or maybe a faulty injector on that cylinder.

 

[DIS1KRAZY]

I saw similar in an 2nd gen I bought once, but a pice of piston was actually broken into the cyclinder wall and the spark plug was broke.

 

[98ls1ttop]

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[Boost92awd]

That piston looks brand new. Whats the story behind the motor? Was it just rebuilt and then blown up again?

 

[98ls1ttop]

well supposedly its all original motor. with 140xxx miles. story is, guy had the tranny rebuilt, and a new clutch, and soon as he got it all together, he pulled out on the road and when he hit second gear (dont know how much throttle or anything, car is bone stock) the car went kaput. he did a compression check on it and found there is 0 compression ....across the board. so he let it sit til i came along and bought it. all the pistons look newish like this one but only this one has something wrong with it. timing was off and valves were broke, so i guess it detonated in that cylinder and broke and bent all the valves at the same time???? (other cylinder valves were bent or broke)

 

[1stgendon]

Damn that sucks.

 

[xdxoxuxgx]

That's some serious damage haha, when stuff breaks that always means it's time for an upgrade.

 

[layzie12g]

whoa that sucks. Maybe a bad injector. Im not sure what else could cause that in a stock car.

 

[crimsondragon]

I don't see a problem at all. I see an opportunity.

 

[98ls1ttop]

i bought the car to build so it doesnt hurt my feelings that the piston is toast. I would like to know what the heck caused it though, and why the pistons look new if its never had any work done to it. one of the plugs was really white also....not this cylinder plug tho.

 

[1992awdlaser]

Pistons will look new if coolant was leaking into the cylinders.

 

[98ls1ttop]

i thought about that but there is no coolant inthe oil. and the condition this piston is in.....if the head was cracked or bad headgasket it would surely have some antifreeze in the oil. oil is black and actually full. so it must of just happened and parked.

 

[Defiant]

Valves bend when pistons hit them, from jumped timing. Any piston in a chamber getting hot enough to melt will cook all the carbon off it. Sounds like a typical DSM that's been beaten like a rented mule.

 

[Jst4Cyl]

^^^ I love your analogies.

 

[98ls1ttop]

Valves bend when pistons hit them, from jumped timing. Any piston in a chamber getting hot enough to melt will cook all the carbon off it. Sounds like a typical DSM that's been beaten like a rented mule.

i know how valves bend....but what else is ironic is there is no signs on the pistons from the valves.....

 

[stockfornow]

It doesn't take much bend a valve/valves, and that piston looks like it was running lean... Crappy fuel, on the hot day or something. It's a possibility that it blew a piston like that first and then something else happened, such as oil pump seized, bs belt broke, or who knows. Anyway good luck with your build!!!

 

[Red2OTalon]

Sounds as if you have quite the stumper here. I know these engines are interferance, but if it did jump time enough you'd think you would see damage to the pistons in some way... steel valves vs. alum. pistons... (i remember back when you old cavalier jumped time there was little dents in the tops of the pistons where they clashed with the valves)My only theory would be detonation.

 

[1992awdlaser]

Maybe that head came off another car. Then the previous owner tried to fix your car with that head or something. And it didn't fix the problem because the valves were bent.