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Guys,

I'm just interested in your opinion about how following damage might have happened.

A (good sofar) Mopar shop rebuilt my 440, bored and honed, Keith Black pistons, Alu Stealth heads (440 source).
Crank was balanced ect.
I drove the car for about 200 miles and it did good. Except for a rattle when accelerating with full throttle.
Two weeks ago the rattle became loud very shortly, engine died at once and white smoke from exhaust....
Car was brought back to the shop, and the engine was opened. They found a crack in a cilinder, and that piston was badly damaged.
The heads and valves seem to be undamaged. But will be totally checked.
So, they will repair it all, maybe with another 440. And it all falls under garanty, it was their fault. So that is the good news.

But, what could have caused this? The reason they give puzzles me.
What do you guys think might have caused this damage?

Is the top ring still intact? When I purchased my KB pistons I read about proper ring gap being critical on these pistons. They could butt. together and pull the top ring land apart if they are set too tight. That's what it looks like to me. Just a thought.

Man that sucks. Hope they get ya back together soon. Good deal they stand behind it and it wasn't a total blow up.

That "Rattle" you mentioned is what killed your engine. Its called "Pre-Ignition" or "Detonation". Poor fuel octane rating, compression ratio too high for fuel, too much ignition advance, ALL individually or in combination can cause detonation resulting in what you now have for an engine. The instant you heard that "Rattle" you should have STOPPED driving the car and corrected the problem before going any further.

From the wear in the cylinders, that piston was rocking pretty good on the up/down strokes. I'd lay odd on some serious detonation like M&M said above..

Look at the rod bearing to the right of the one that's busted, that's some serious wear for such low mileage, which is what you'd usually see in a motor that is detonating.

X2

Mopars & Missiles' Wrote:That "Rattle" you mentioned is what killed your engine. Its called "Pre-Ignition" or "Detonation". Poor fuel octane rating, compression ratio too high for fuel, too much ignition advance, ALL individually or in combination can cause detonation resulting in what you now have for an engine. The instant you heard that "Rattle" you should have STOPPED driving the car and corrected the problem before going any further.

RT K_line Wrote:Is the top ring still intact? When I purchased my KB pistons I read about proper ring gap being critical on these pistons. They could butt. together and pull the top ring land apart if they are set too tight. That's what it looks like to me. Just a thought.

Not sure if the top ring is ok.. I'll ask the guys.

"Pre-Ignition" or "Detonation" could very well be the cause. Does that rattle sound like a mechanical rattle? If so that just might be it..
I'll share your thoughts with them.

Stargazer Wrote:But, what could have caused this? The reason they give puzzles me.

Stargazer Wrote:....Does that rattle sound like a mechanical rattle?

..........I'll share your thoughts with them.

What other kind of rattle is there??
Actually, I'm interested in knowing what they told you caused this problem?? Also, who the engine builder is??

Not to disagree with everyone, but my vote is the ring gap was too small. Notice the shiny spots in the cylinder where the ring wore, nothing like that on the adjacent one.