Engine/Transmission (1998.5 - 2002) Comments on Cummins Overrev?

[DieselB59]

Suppose when the mechanic who pulled the head, upon putting the head back on, didn't seat the ball end of the pushrods back into the seats of the tappets on that cylinder. The tappets could cause the pushrods to jam up and bend inside their passages and force them up high enough to hang a valve open. Look at at the S shape of the pushrods in the pics. It is possible. It could have been driven for a while like this until it really got bad and hung up for good. The final wrecking ball comes in when Mr. Piston comes up and slaps the valves, which are jammed open, bending them, breaking the rockers and bending the pushrods even further. No other reason in the world of logic can substantiate why that happened. I have personally seen a 12 valver lose governor control and rev to what was going back to the zero mark on a tach. After throwing a block of wood over the throat of the turbo, she was brought back to life without any mechanical failure. Maybe the mechanic who doesn't know anything about cracking the injector lines loose to initially fire the engine after putting the head on went way overboard and tried starting the engine with starting fluid and that was when the high overrev was recorded.

 

[Extreme1]

Lots of possibilities...

But the facts are:



The valves on #2 are bent.



The valve train is damaged.



That's all I see FOR SURE. There seems to be some confusion as to what work was done. As for the codes, after a failure like this, there are going to be all kinds of erroneous codes. You can't necessarily determine turbo or injector pump problems from an engine with this kind of damage.



So, lets stick to the facts. Well, gee, something had to cause the piston to contact the valves. A broken cam, failed cam drive (would also not drive the pump) or broken crank would all do this. (saw a small block chevy do it once, ran on 6, shook bad, when he shut it off and tried to restart, it only turned over the rear 2 cylinders and not the cam!) Killer dowl pin anyone?



Another consideration: a dually has lots of traction in a pull start situation, dirt road or not. Especially if a working posi and weight in the bed. It could have been in 4 wheel drive.



As for the bad repair possibilities, since we don't know for sure what was done, we can't speculate. The customer should have the slip (or have access to it) and it will show the parts charged to the repair. I agree, the head should have been replaced if the valves were bent at the first repair. A close examination of the repair slip should show what Chrysler thinks happened. Unfortunately, a teardown is required to determine the effect from which a cause might be able to be determined.



As for the actual mode of failure for an over revved engine, the reciprocating section (crank, rods, pistons) will be the source of damage. The rods will stretch and allow contact before the valves would float that far. After stretching, the rods would break unless the forces on the crank got too high and it broke. The pistons probably wouldn't "fail", but they sure wouldn't survive either.



Doc, we need more info! Get the info from the repair slips, this could provide the direction we need.

 

[Doc Tinker]

I think DieselB59 hit a good point, with his comment on the starting fluid. That could very well be what caused the over-rev.



I believe that the mechanic replaced the turbo and injection pump in a 'replace and see' scenerio. These items probably were not bad, but the codes indicated they had problems. I found out how easy it is to trip codes the other day, when I got a P0100 from messing with a relay. See: http://128.242.249.86/forums/showthread.php?s=&threadid=21605



Doc

 

[Doc Tinker]

Here's the latest in the saga of the over-rev story.



The Colorado mechanic's RO is entirely handwritten. Here's what it says:



"Check knock noise in engine compartment. " (that would be all he shows as the owner's complaint. ) Then he writes, "found rear pistoin slapping cylnder. replace short block. not necessary to remove trans. "



On the parts list, if read correctly, the items used are:

"1- R5015092AA - block

1- 5011933!! gskt pkg - C

1- 5014528AA - gskt pgk - L

1- 4425015 filter change The number is marked through and written underneath it is another number

- 5016547AA

11- con 15-40w - npn

2- 4267020AG - coolant

2- 4669020 - lmbel (sp?)- fluth(sp?)

2- 4275066 - label -"

 

[Doc Tinker]

I just heard from the lawyer, on this case, and he's finalizing his investigation and will be finishing up in court. He's certain that it will end up on a possitive note for his client. He wanted me to thank those who've contributed information and opinions on this thread.



Doc

 

[Jetson]

So do you think the mechanic that replaced the block had the cam out of time? That could cause the poor running condition. I have had a piston hit the valves because the rings seized in the cylinder which tore the piston in half(in a gas engine). The top half would get knocked into the valves by the bottom of the piston. A broken camshaft could also cause the piston to hit the valves, but it doesn't seem likely in this case.

 

[NScott]

96' with the same problem?

I just bought a 96' Cab& Chassis 3500 with 5 spd. and 4:10 ratio.

It was sold "as is" and I knew it had motor trouble before hand. It was used as a service truck by a petrolem pump company and they said it had problems while on I-24 and they had to have it towed in. They took it to Southeast Diesel and had it checked out.

Southeast said that both push rods on #3 cylinder were bent, so they replaced them but the engine still had a dead miss on #3. They ran a compression check on #3 and found that it was down.

The engine seems to run ok other than a dead miss on one cylinder. The oil pressure is okay, there is no abnormal noises or grinding that I can here. There is no oil in the coolant or coolant in the oil. The only thing I know to do at this point, is to take the head off and see what everything looks like. I don't know what else it could be other than a bent valve. It seems to me that if it was piston trouble (cracked, come apart,etc. ) that you could here noises from the area. Would'nt it be raising *ell? Any other ideas??