What caused this?

[stock]

Here is a picture of a 4cyl turbo motor head. I know we will never know what actually caused this failure but I would like to see what you folks say.......

 

[d9gdon]

Looks like the turbo came apart, got sucked in the cylinder, and got hammered into the piston and head.

 

[stock]

Strangely this was the only damaged piston, no marks on the block/liner, turbo is fine.....................

 

[Willis Bushogin]

did it drop a valve?
how is the connecting rod bearing, for this piston

 

[DPete]

I'm like Willis, looks like a dropped valve via broken spring or keeper came off or the valve broke and the piston drove it into the head

 

[Nige]

Judging by the bits missing off the RH valve in the photo it looks "guttered" - a common issue if valve clearances are too tight. What is the previous history of valve adjustment on the engine..? Are the valve stems above the head all in one piece, no broken valve springs or missing keepers, & valve rotators in good condition..?

Personally just based on that one photo I'd say the valve on the RH side has failed first and a piece or pieces broken from it have been caught in between the piston and the other valve which in turn has taken out the valve on the LH side of the photo.

 

[Scrub Puller]

Yair . . . From the evidence presented I think Nige's theory is pretty right, it would be unlikely that the hot end of the turbo didn't have at least some scars.

Cheers.

 

[qball]

termites.

 

[rafi]

hi all.. Im new member in this forum. Many cases damaged parts like on pictures caused of valve gattering, agree with nige. But i have question, did there is no other damaged part on others cylinder or push rod bent, sign of lack lubrication on rocker arm or maybe any sign of overspeed ?

 

[BRIEV7]

Hi , I agree with DPETE, because I 'd same experience with my dozer 850J

 

[Axle]

Nitrous involved in this?
I'm going to guess some sort of coincidental injector and valve failure dumping fuel, causing the solidified lava look, dropping the valve somewhere early in the process. If it was just a valve I'd expect only a mechanical beat down.

 

[gabsgarage]

Looks like a valve seat got loose in the head, rattled around and broke into pieces, I can see curved pieces beat into the piston dome.

 

[alrman]

Alot of heat required to make a piston look like that ...... The question is what happened first? - the valve failure or the super heated piston? Like Axle says some type of fuel problem.

 

[Nige]

Looks like a valve seat got loose in the head, rattled around and broke into pieces, I can see curved pieces beat into the piston dome.

I can't see anything in those photos that suggests a dropped valve seat. From what I can see both valve seats are there. The curved piece embedded in the piston is a piece of valve.

Alot of heat required to make a piston look like that ...... The question is what happened first? - the valve failure or the super heated piston? Like Axle says some type of fuel problem.

Aluminium piston crown + loads of fuel from the injector that got destroyed when the valve debris hit it...? Depends how long the engine ran after the failure before being shut down.

 

[rare ss]

I'd be thinking maybe the injector failed, leaned out and melted the pistion, what does the bore look like?

 

[MrKomatsu]

Water on top of a piston can really mess it up....just sayin......

 

[gabsgarage]

The intake valve seat is gone. It got loose in its bore and fell out. It got trapped by the intake valve and when the piston came up and hit it, the seat fragmented, That's what bent the intake valve. The pieces of hardened valve seat got beat into the piston crown-which mushroomed the piston- which now is too tight in the bore and generating heat. I've seen it happen dozens of times. No fuel problem, or detonation problem, or advanced timing causes damage like this. This engine dropped an intake valve seat. NO mystery here.

 

[gabsgarage]

You can't see that the intake valve seat is missing? Better look again.

 

[Hendrik]

Does this engine have piston cooling oil jets.