Big Engine Damage

[gatotom]

daepp, you got to not treat that truck like your Porsche easy on the throttle not pedal to the metal.

[afterburn 549]

The bent push rod says something stopped upstairs , It might be an over rev .
Most todays modern computers will tell you as in " tell tail" if Over speed was a problem.
It certainly looks like a couple different problems synchronized as in structural failure with the cam.
One may have exasperated the other?
Sorry ma it sucks
I have not ever had any luck with cummins either just for 20 20 hind sight...(cumaparts) I have owned about 3 855s and one ISB , they have all been delightful awfull .

The best one has been Detroit Series 60 ! By a million miles with out pulling the heads ! i have owned 3 of those

[daepp]

Thanks for all the good info. The truck had begun to experience problems when we took it to a reputable diesel repair shop. It came back with a new knock. So whoever suggested there were two problems I think that is probably the case.
While a miss shift is always possible, I have a pretty good driver for this particular rig. And since he's paid by the hour, I seldom catch him speeding
Finally, oil pressure was never a problem.

[KevinP73]

Looks like oil starvation caused the roller in the lifter to seize up. Overheating the cam. Would need to see pics of other related pieces to know for sure.

[Arizona_928]

That is crazy. Is it possible it's an aftermarket cam?
I would suspect Navistar's QC department to be higher, as these engines are generally considered bullet proof. At least the earlier ones.

[afterburn 549]

Like I said and afaik you can look inside the computer for details of oil P, RPM and etc.
Or at least, that is what i was told by a tech several years ago.

[Nostril Cheese]

Oil starvation up above would be my guess too.

[DanielDudley]

I have seen oil starved valves weld to the guide. In an overhead cam engine they get pounded free. Someone needs to look at the oil galleries. That engine was either run really dry for a fairly long period, or there is some other oiling issue. That did not all just happen in a day.

[daepp]

Originally Posted by KevinP73

Looks like oil starvation caused the roller in the lifter to seize up. Overheating the cam. Would need to see pics of other related pieces to know for sure.

Hey Kevin - what other images would help. I may be able to get some.

[wdfifteen]

It's been a while since I was in materials class, but isn't that spalling a result of surface overload? And aren't those striations in the pit evidence of fatigue?
I'm still going with bad metallurgy in the cam.

[porsche4life]

Originally Posted by AZ_porschekid

That is crazy. Is it possible it's an aftermarket cam?
I would suspect Navistar's QC department to be higher, as these engines are generally considered bullet proof. At least the earlier ones.

The early Dt466 is a bulletproof diesel, used in about everything. Great engines. The newer ones have issues with emissions and electronics, bit not mechanical. Something else is going on. That cam was faulty, or something..,

[Tobra]

So was that cam made out of playdough or what?

[KevinP73]

Originally Posted by daepp

Hey Kevin - what other images would help. I may be able to get some.

Pics of the failed lifters would help. The wear marks appear to be made from roller lifters. And maybe a pic of the rocker assembly might give a clue to what failed first.

[daepp]

I think the only parts I have left are a couple of lifters, and I didn't keep track of where they came from. What little I saw of the lifter from the bad lobe it didn't (to my untrained eye) look bad.

My mechanic did say that the engine had at a minimum had the head gasket replaced before.

And as to Sid's comments, I agree on both fronts - the DT466 is an awesome engine, but the emission control systems ruined them. Over 50 sensors, two water coolers for the egr, the particulate trap and the regeneration system. They conspire to make the thing very unreliable.

And all that on a diesel that can run and run without so much as an ignition system...

[aigel]

How does the pushrod get bent from poor cam oiling / wear? It just moves up and down with the lifter / lobe. Something smacked the valves. The lobes look worn on some images but others it looks like something hit them.

G

[KevinP73]

I would suggest that the bent push rod, providing it came from an adjacent cylinder is more likely collateral damage after the main event disrupted normal operation. Main event was lifter failure causing the cam to stop suddenly, timing chain fails or at least slips allowing the next cylinder in progression to experience valve to piston contact. Causing the push rod, being the weakest link in the assembly, to bend.
It's all just speculation not seeing the engine for myself.

[unclebilly]

Assuming this has a non-synchro trans, I doubt it was severely over revved unless there was a big hill and no brakes.

You can't rev match to do an accidental downshift in a big truck - it won't go into gear.

When was the last oil change?

[Dansvan]

Let me start by saying I know nothing about THIS engine. The bluing around the lobes is from heat treating. But look at this pic...




See the bluing around the lobes on the top two styles? None on the lower roller cam... Did someone install the wrong cam or the wrong lifters? I don't know if all the roller cams are built this way for this engine, but this pic leads to some questions.

Oh and they also repair them

[daepp]

Originally Posted by KevinP73

I would suggest that the bent push rod, providing it came from an adjacent cylinder is more likely collateral damage after the main event disrupted normal operation. Main event was lifter failure causing the cam to stop suddenly, timing chain fails or at least slips allowing the next cylinder in progression to experience valve to piston contact. Causing the push rod, being the weakest link in the assembly, to bend.
It's all just speculation not seeing the engine for myself.

- What I saw of the pistons they had no valve/piston damage. Timing chain looked normal as well.

- The engine idled fine even with all this damage. Maybe a bit of smoke but nothing to write home about. It simply lost power and sounded bad.

- In the last 6 month it threw a lot of emissions codes, and went into "regeneration" mode quite a few times. Regen is when the brain detects excessive back pressure in the particulate trap, revs up and dumps raw diesel into the trap to burn it out. The turbo had a bit of oil residue on it that the pros said indicated that it needed re-sealing - which we did. Another expert, however, said that since there is not crankcase vent on these newer diesels that all the turbos get oily reburning the crankcase gasses.

- While I've owned it the oil has been changed every 5000 miles on the dot. But I bought it used.

[daepp]

Originally Posted by Dansvan

Let me start by saying I know nothing about THIS engine. The bluing around the lobes is from heat treating. But look at this pic...




See the bluing around the lobes on the top two styles? None on the lower roller cam... Did someone install the wrong cam or the wrong lifters? I don't know if all the roller cams are built this way for this engine, but this pic leads to some questions.

Oh and they also repair them

The top two cams look blue around the shaft, but the lifters ride against the lobes right?

Perhaps I'm just not experienced enough to understand your point.