Big Cam 855

[Paychk]

Any one on the forum that works with these? I have a few questions.



My brother has this engine in his truck and at 400,000 miles it burnt a hole through the piston. Apparently the injector started to dribble, is there any way short of pop testing the injectors to detect when one is dribbling? I figured one way would be to put a pyro on each cylinder and monitor the exhaust temps..... but that is a lot of gauges to monitor.



I would appreciate any and all help!



TIA

 

[truckstom]

Which ever piston is burnt, that's the injector to check, ... is this engine still set to factory specs??? Sounds like someone "turned up the pump" You can get massive horses and torque outa that NTC, but the stock pistons will not hold up... .

 

[Paychk]

It is turned up. This occurred in one hole only, anyway he did an in frame major, the only parts reused were the crank, cam and followers. All the injectors were replaced. I suggested that it might be worth it to pop check the injectors annually. Is there any way to monitor the engine, to prevent this from happening again?

 

[jmeehan]

The 3500 series Cat generators that I work around use pyrometers on each cylinder and alarm systems to notify you when one cylinder is getting hotter then the others. I don't know if anyone makes a system for over the road trucks but you may be able to make a marine type system work.

The Cat panel also has one gauge and a rotory switch so you can turn it and check each cylinder.

I can see where you wouldn't want to do this to much while driving but even an occasional glance at the gauge and turn the knob would be better then nothing.

 

[power grizz]

if the truck misses on a cylinder when cold, feel the manifold with your hands to feel for the poor cylinder(injector). if it starts fine(no missing)then you would have to pull injectors. i thought you could test them for dribbling by pulling up and dropping the injector pushrod(with injector out and in your hand) back into the injector and if it didnt drop it was good or if it dropped in the it would push fuel out the end and be bad.



i think this is right, i haven't worked on a 855 ntc for a few years. or call a injection shop and ask them they should tell you what to do.

 

[truckstom]

Originally posted by Paychk

It is turned up. . Is there any way to monitor the engine, to prevent this from happening again?

Pyrometer. Drive by it. http://www.dieselinjection.net./



Check with Bruce also... He builds HIGH horsepower NTC's everyday

 

[Paychk]

The engine has one pyrometer on it, not sure of the location before/after the turbo, evidently there was little to no temp change leading up to the failure point.



Thanks for the suggestions!

 

[Camara]

When we had trouble with our engines (smoke or a skip) I would loosen up the exhaust manifold and back it away from the engine. Start the engine up and which ever hole smoked, that injector was the culprit. Believe me when you start them at an idle you can see a difference in the smoke between cylinders. Pay attention to the stacks. Not only do they let the smoke out they will tell you a story.

 

[jimk]

injectors

pulling the manifold is the way my father told me how to check the timing in a D6 cat older model. He said to pull the manifold to see which cylinder is running out of time by looking at the ports. He told me that it will be blowing smoke rings and missing.

I try to remember all of the tricks he tell me in case I need them.

I have learned that i don't have to learn the hard way all of the time. JimK

 

[Vaughn MacKenzie]

truckstom. . . Wow this is a dyno day I would've loved to attend. . . bigrigs putting around 1000 HP to the ground, I can only imagine the sound coming out those big chrome stacks



Oo. Oo. http://www.dieselinjection.net/alban/



Vaughn

 

[truckstom]

Originally posted by Vaughn MacKenzie

truckstom. . . Wow this is a dyno day I would've loved to attend. . . bigrigs putting around 1000 HP to the ground, I can only imagine the sound coming out those big chrome stacks



Oo. Oo. http://www.dieselinjection.net/alban/



Vaughn

No doubt about it!!! An awesome ground pounder... I know a guy that had Bruce build his KTTA Cummins. he said loaded out at 92000#'s it accelerates like his CTD. Empty it will chirp the tires at 85 mph...

 

[Gizmo 007]

We've had problems in the past with them cracking injector tips. I had one blow a tip completely off! I knew it immediately, cause the pyro went nuts, and it lit up the front of my trailer. It happened at night on a long road trip, and another driver came over the radio laughing, said he liked the flaming stacks... I didn't think it was funny :{



As far as testing individual cylinders, you can use an infrared thermometer (thermal gun) and shoot the individual cylinder exhaust ports. Of course, this method doesn't help on the road. I'd almost put money on a faulty injector. They can and do break / wear out.



Good luck!