I cirlced the area in red where it appears part of the valve seat is missing.

 

That is the exact spot I was talking about but on second look while zoomed in I'm not sure. If you zoom the pic way in it looks like maybe carbon is built up everywhere but where you circled.Making it look like part of the seat is missing when really it's just a clean spot. I really can't be sure though. I'm wondering if the spot just above the circle is really the problem because the carbon build up is the worse there indicating a possible leak?

 

Yes there isn't missing a part of the seat that is carbon. I want that to tell you but I didn't know the right word. But it's carbon

 

I would still remove the valves from that cylinder and inspect them as well as the springs and retainers. I bet the valve that sits above the damage on top of the piston has a problem you can not see in these pictures. Under the head of the valve there is a "seat" that the valve seal against. These seats are pressed into the head, and on these engines are know to fall down and hold a valve partially open causing it to contact the piston. Keep searching.

I also still suspect the injector for that cylinder unless it has been tested on a bosch test stand for proper operation.

 

Looks like the piston was overheated from fuel and started to deteriorate.

 

you have pyro gauges?

if yes how high was it?if not to high pyro temp?

to much fuel on this piston? if banks six gun the problem?

chris

 

Take the valves out of the head. The seat could have just reseated and is moving in/out of the head when the valve opens/closes. It probably just hung up and hit the piston.

How high of temps had you seen on your guages?

 

That area you circled just looks like a place where the carbon build up fell out.

Mind you the carbon build up is combined with aluminum particles.

 

That injector was over fueling, you can see from the pictures looking at the top of the piston where you have the carbon lines running from the center outwards. You have four definate lines and one missing.
This tells me that your injector is not spraying properly, one hole is clogged and the others are over spraying.

Have the injectors bench tested especially the one for that cylinder. If you need a recommendation as to who to send them to I can PM you one. or find a local Cummins shop or diesel injection shop locally.

I agree about the valve looking like carbon fell off.

 

The EGT's where somewhere around 1100/1150.

I will give al this info to my neightbour.

Does anyone know what the price is for an new block? Because that's maybe cheaper then getting this one repeared.

 

That cylinder does not look to far gone from the pictures. How deep are the scores in it? I don't believe a new block will be less than fixing one hole. Keep us updated.

 

We are gonna take the motor out and then let them give a price what it would cost.

My neightbour say's they need to drill and put can's in there.
I don't know if this are the right word's but this is how we say it in dutch.

 

Cummins does have a salvage sleeve kit made for the 5.9. I would pull the suspect piston only and inspect that one hole. If it is not all scored up then mic the cyl, if it is still good then hone clean it and put a new piston in it. It can be done in with the motor in the truck. I would most definitely send the head out for a complete disassembly and overhaul.



Tim