toasted cylinder #1

[DieselB59]

Well, now I've seen it all. I had a truck come in on a tow truck... the owner said he was taking the head off because something bad happened and it was beyond his ability. I popped the hood today and just lifted the head to see inside... cylinder #1 is mangled, and the piston looks like a half melted candle. I will get some pictures posted as soon as we get the engine out. This one is impressive, don't know if the injector failed and stayed open to get a secondary pulse of fuel or what.

 

[Cummins Corvette]

What is this guy's settup?

 

[DieselB59]

Bone stock with only 100K. Pump is not touched, and all is otherwise stock too. :--) I don't quite know what to think, but haven't gotten a close enough look to see what else can be pieced together into this mystery.

 

[Cummins Corvette]

Bone stock what?

 

[DieselB59]

Bone stock our brand 1995 vintage.

 

[Don M]

Im wondering if the candle, so to speak was caused from the cooling nozzle being blocked. My understanding is the piston will sieze not melt though.



Maybe he had a piece of trash in a nozzle seat and the thing just rolled in too much fuel to that cylinder causing the overheat.



Cant wait to see what it is.



Don~

 

[DieselB59]

It may take me a couple days to get the engine out and dissassembled, due to a couple of sick-fives tying up the bays, but when it is out and apart, I'll get some photos posted.

 

[R.ebel]

Toast

Chris,

Have you tore it down yet???

 

[dseabaugh]

piston meltdown

i had a four wheel drive tractor do that with only 300 hrs on the engine. One of the injectors started peeing a stream for some reason and it just melted down one side of the piston. what a mess.

 

[DieselB59]

the plot thickens.......

At lunchtime, I went out to the lot with another tech and I lifted the head so he can feel around. Along with some alloy balls, we found the intake valve, minus its stem. It looked quite melted along with the rest of the piston and cylinder wall. Strange thing..... the stem is still sitting pretty in the top of the head, spring and all. The 6. 5 is still in my way of progress, but hopefully, I'll have that running by 10am so I can bring in Three Mile Island Cummins and start ripping it apart.

 

[Don M]

Chris, pop testing the injector might give ya an idea if the injector was hangin up and poorin' the coals to it.



Don~

 

[DieselB59]

The thing that the injector could have been doing is injecting properly, then, when slamming shut, the shockwave of fuel suddenly reversing direction could have opened it to cause a burn that was out of time. But, until I see further inside, there's no telling what else could have contributed to what very well could be a multi-faceted problem.

 

[Don M]

I had an injector that was pooring fuel in like crazy. When I removed the head, there was about a tablespoon of fuel and half burned fuel in the top of the piston chamber. Prolly more than a tablespoon now that I think of it. The little dome inside the chamber was nearly under fuel. The injector had a piece of trash in it causing the injctor to never close up. The seat was blocked from closing to the needle.

Just some thoughts.



Don~

 

[Pthomas]

:-{} could be this could be that .

cant wait ? me either i love to learn.

did i understand one of the valves broke off in the cylinder?

 

[DieselB59]

I don't know if it broke off or melted off, the remains of it definitely show that it had been molten. It's inside now and the motor should be out by tomorrow evening.

 

[dseabaugh]

meltdown (chernobyl truck?)

What usually happens is the injector nozzel get plugged from unclean filter change, something coming apart or nozzel looses its pop off pressure and pees a stream the fuel lays on top of the piston and burns instead of being vaporized. piston starts to melt down. then balls or globs of piston try to go out with exhaust gasses and get caught between valve and head. valve pops off stem if piston doesn't hit it first. Major mess. lot of times wastes the turbo too. :{

 

[DieselB59]

And the diagnosis is......

Okay, boys and girls..... here is what I can figure out. The truck came from another shop, where the guy gave up on it. It looked like a bomb went off in cylinder #1. I talked to the shop today after I ripped down the engine. The shop owner told me that it came in with a broken exhaust valve spring. I took that info and figured out a short list of what happened.

1. Valve spring breaks in a freakish accidental manner.

2. Exhaust valve plummets into never never land, then gets smacked by piston.

3. The valve, bent and hung open, gets smacked several more times until it breaks free from the stem.

4. The valve, along with several clumps of aluminum pummelized piston material, does the mambo with the remnants of the piston, breaking off the injector tip and breaking the head into a non acceptible core.

5. The piston, from the impact, becomes bell-shaped and cracked along the skirt, similar to the liberty bell.

6. The cylinder bore, from the pressure, succumbs to the oversized piston, and cracks vertically, four inches long.

7. Net result, unrepairable engine, head and blown apart turbocharger.

New engine's on the way.

Pics are taken and will be posted as soon as I get a minute of feedom... . as a KDP injury has arrived and that means another busted B series will be dissassembled side by side with the first engine.

 

[Cummins Corvette]

Is cummins gonna cover that?

 

[DieselB59]

Unfortunately, the engine was just over the 100K mark. Rare, but shocking to see.

 

[Cummins Corvette]

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