I found where all those parts came from.

#4 cylinder only and the block looks fine

When I removed the slug all big pile of ring and piston material fell to the floor.

It looks like I was driving around with a damaged piston for awhile. Some of the area where the piston is broken you can see it's not shinny like other places.

 

Nice job Dwayne.

Looks like a typical cast piston failure from hit'n the bottle too hard.

And you didd't notice you were down on power? Or did you just start using oil? You had said you had water in the oil. Sure you didn't push out a head gasket too?

Barry F

 

I've been using oil for the last 5k miles. Yeah kinda down on power but not hat much. I thought fouled plugs and cap/rotor.

I've looked hard at the heads, block surface and gaskets for a failure point. So far nothing really shows any sign of failure between the head, gasket and block.

I was having oil spewing out of the dipstick at above 5k RPMs but I thought that was because I put in an extra 1/2 quart of oil in my last oil change because I used a shorty filter instead of my usual long type.

How could Nos break the middle and oil ring? I thought it would have damaged the upper part of the piston. All the other slugs are fine and the rings look great.

 

weak point on cast pistons is the lands. If you don't have a wider end gap the higher ring temp will cause the ring to close up and stick in the bore. then the next thing is for the land to start pounding and you end up with what you have. It's common. Usually a lean condition will cook the piston and/or crack/melt it.

Don't you run a 150 shot? I wouldn't run over a 100 on a stock motor unless is has good factory internals. (forged pistons, chrome/moly type rings, forged crank, etc.)

Barry F

 

I only used a 100 shot.

If the ring stuck to the bore wouldn't it be visible when looking at the bore now?

 

It could have just closed the end gap enough to slightly stick and/or cause more strain on the land. look at that part of the piston on another good piston. you only have about 3/16" material there.

It could have been a number of things but the NOS didn't help

Barry F

 

Yup thatsa for sure!

I may have found a good deal on a Superram top and runners.