Deuce multifuel engine damaged piston burned/ overheated!!

[tm america]

i would think a clogged injector which would caue a lean condition which could melt a piston due to detonation

 

[EveOfDestructionDeuce]

Sounds incredible that the engine will be damaged and the truck are not useful anymore in a mission of war, because of a defect injectorHear they designed the M-engine that it could also run with a faulty injector w/o probs.

 

[clinto]

Something no one has covered is cracks in the top of the pistons. I have pulled apart several multifuels and all of them had small cracks around the swirl chamber in the top of the piston.

I have some pictures at home and if I remember, I will post them after work.

I do not know if they are caused by inexperienced (or careless) drivers lugging the engine or the multifuel's 22:1 compression ratio.

 

[EveOfDestructionDeuce]

And faulty injection timing can`t do that? I adjust the pump as follows. TDC mark on vibration damper lines up with mark on timing gear cover (middle line mark which say LDT-465-1C), I turned pump driving gear slot holes so that the front timing mark at the pump also line up (sitting on top under the small angular cover w/4 small bolts) The other red tooth mark at the gear which drive the hydraulic head did not line up with the timing mark (sitting under cover near engine shut off rod at the side of the pump) and was far away over 1/4" from that position. There was no way to line them both up, I tried also 2 times 360degr. Friend of mine disassembled and cleaned the pump, may be it was possible to put in the hydraulic head drive gear w/shaft in many other directions.....

 

[EveOfDestructionDeuce]

...

 

[Coal Cracker]

i would think a clogged injector which would caue a lean condition which could melt a piston due to detonation

a clogged injector will cause a lean or no fire condition,a leaking injector will cause an overfuel condition. An injector is merely a valve of a sort, machined surfaces with a poppet and springs, if a part had gotten moisture on it, or maybe moisture was in fuel system, and sitting that long, it'll cause damage..


An easy way to tell if it is in fact injector related, you need to find an injection pump, injector rebuilder so they can be put on a flow machine, and you'll know right off the bat what's going on.


There's a company near me(Fuel Injection) in Allentown ,Pa. Phenomoninal people I've taken allot of thought faulty /leaking injectors to them, and either had them rebuilt or replaced, in eve of's case i would mark what jug they we're feeding, and have all of them taken to a shop.

 

[JasonS]

How can a "lean" condition in a diesel cause damage? Isn't that akin to a freewheeling cylinder? How about at idle where the whole engine operates lean?

 

[Chief_919]

That looks a lot like one injector was providing more fuel than the rest, leading to an overfueling that led to an overheaded cylinder. usually when I see that however the other cylinders will at least show some signs of overheating.

Now, why just one injector? I don't know. Do the part numbers all match on them?

 

[mistaken1]

I am not a diesel mechanic, I don't play one on TV and I did not sleep in a Holiday Inn last night but based on this statement and the photographs "the truck stops, engine knocks, no power, black smoke and goes out," I think it is over fuel in that cylinder.

You said the IP had issues including a stuck fuel cutoff so I am thinking that the injector for that cylinder did not close properly and the excess fuel caused higher temperatures and pressures. Perhaps if all the fuel was not burned there could have been liquid fuel in that cylinder that does not compress leading to a damaged piston and bent rod.

The operators manual talks about turning the engine over before starting (fuel shut off out) to check for hydrostatic lock.

 

[EveOfDestructionDeuce]

I disassembled the injector completely and there was nothing wrong, no dirt/rust e.g..all looking fine and the jets/nozzles are free, I`ve tested with compressed air.It was also full with diesel, injection lines from the pump are also free.
A lean burn can`t do a problem like this, because the liners are oiled all the time from the engine oil.....

 

[littlebob]

I am not a diesel mechanic, I don't play one on TV and I did not sleep in a Holiday Inn last night but based on this statement and the photographs "the truck stops, engine knocks, no power, black smoke and goes out," I think it is over fuel in that cylinder.

You said the IP had issues including a stuck fuel cutoff so I am thinking that the injector for that cylinder did not close properly and the excess fuel caused higher temperatures and pressures. Perhaps if all the fuel was not burned there could have been liquid fuel in that cylinder that does not compress leading to a damaged piston and bent rod.

The operators manual talks about turning the engine over before starting (fuel shut off out) to check for hydrostatic lock.

I remember reading that but had forgotten since mine is not yet on the road. As little as I start mine now and probably in the future, I probably go through the manual and creat a laminated check list for start up and shut down like pilots have untill its ingrained in memory and to educate anyone else that may drive it. Thanks

 

[dk8019]

It's sounding like they think it was injecting too much fuel, not to little if I'm understanding this correctly.

 

[EveOfDestructionDeuce]

Yes that`s right, but both of this could not do this I think...Otherwise overfueling will produce black smoke and there was nothing before the engine begins to stop

 

[clinto]

Something no one has covered is cracks in the top of the pistons. I have pulled apart several multifuels and all of them had small cracks around the swirl chamber in the top of the piston.

I have some pictures at home and if I remember, I will post them after work.

I do not know if they are caused by inexperienced (or careless) drivers lugging the engine or the multifuel's 22:1 compression ratio.

These are out of engines that were under 2K hours and were both running perfect.

Who knows what causes this-Kenny? M-35 Tom?

 

[2Deuces wild]

Wow those cracks look bad. I second hydrostatic lock as the possible culprit.

 

[Parker2]

That melted piston looks like one I just pulled out of my Dodge Cummins. I had a cracked injector nozzle that overfueled big time.
I would suggest having your injectors professionally pressure checked. Also check the exhaust manifold port for that cylinder and see if it has been washed clean. That would be a good sign that it overfueled.

 

[EveOfDestructionDeuce]

Clinto thanks for the pics, really disturbing, the question is was it an individual case

@Parker2 Does the the piston from your cummins same looking ike this one, you change piston/liner and injector and everything was fine?

 

[cranetruck]

What if all cylinders were over-fueled and this one simply the first one to give?
The amount of fuel fed to each cylinder is metered by the IP and should be the same for all. Yes there is an overflow line, but the amount returned to the fuel tank from the injectors is only a small fraction as I understand it.
An EGT temperature would have been useful (pyrometer).

Interesting images Clinto, reminds me of the stress fractures in my flywheel...some are acceptable, some are not...

 

[Parker2]

Clinto thanks for the pics, really disturbing, the question is was it an individual case

@Parker2 Does the the piston from your cummins same looking ike this one, you change piston/liner and injector and everything was fine?

I figured since I had to pull the engine I may as well rebuild the hole thing. I sleeved the cylinder and bought one new piston. All is well and running great. Yes your piston damage looks alot like mine except mine was a little worse.
As for a pyrometer - I have one and was watching it. It turns out if one cylinder is overfueling it doesnt really show up on the pyrometer. The pyro is showing the total of all cylinders not just one.

Looking at the pics of your head. It looks like the valves on #2 are pretty clean. If thats true maybe fuel was washing into that cylinder and cleaning it out. In my case the exhaust ports in the head for #1 thru #3 were spotless. No carbon at all. The fuel luckily didnt hurt anything else, but did clean the head.

Oh I almost forgot that I did have to replace a valve as the metal and heat had damaged it.
I would also suggest hot tanking everything to make sure that there is no metal in your oil system or head. Chances are there isnt any. It probably blew out thru the exhaust, but you never know.

 

[cranetruck]

.....
As for a pyrometer - I have one and was watching it. It turns out if one cylinder is overfueling it doesnt really show up on the pyrometer. The pyro is showing the total of all cylinders not just one.........

Well, the exhaust manifold is divided, so you can install one thermocouple in each and display the two readings on one gauge (center gauge in image below). This arrangement provides a reference in case one cylinder is misbehaving...