Toasted Cam Shaft - Cummins ISX 870

I see most camshaft/rocker failures happen if someone has taken the top end apart once already, lots of mechanics aren't aware of the proper torque procedure of the valve rocker shafts, if not installed properly, it starts with improper engine brake running clearance, which wears out the rocker shaft engine brake detent pockets to an oval wear, and causes your jakes to be weak, then proceeds to cam and rocker premature wear, regardless of proper valve lash, if the shaft is not located properly it doesn't provide proper lubrication.

 

The rockers were all bad, i found on the forums that this is a common problem for cummins ISX
we did an overhaul, keeping same injectors
when we started the engine,it was running good.
but when pulling the trailer even empty, it runs tight.
It feels like somethings holds on the turbo or the wheels, it does not pull like before.
Yesterday In Oh for example, just south of Dayton claiming the big hill @ mm 40-ish, did not go better than 30 mi/h. that with a 80k lbs load.
Is this tight something normal until breaks in? i have a 475 HP ISX , turned to 525 by dr Diesel.
thanx for the imputs.

 

"proper torque procedure of the valve rocker shafts" its all in the book, how can anyone tight them not to the specific torque?

 

You have to have all the adjusters backed off, turn the engine over till the shaft sits on the pedestals and then torque the front bolt to initial torque to locate the shaft then you can proceed to torque the rest of them, I've seen too many people suck the shafts down with the bolts, then torque them.

 

it was done this way, yes.
i will have a dyno test tomorrow, we may have a EGR problem, since engine runs smooth, even accelerated, when push hard it does not respond the way it should (also considering that i have 1800 took and 525 HP).
will come with updates as soon s we figure it out the problem.
Thank you

 

Could be egr issue, the 870 egr valve was a bad one for sticking and if it is unplugged it can cause boost loss, because it need voltage to hold it closed, found this out when testing intake systems.
If all the rockers were replaced then these most likely are the wider roller ones as Cummins had a TIB about them, more contact area less loading sort of thing.

 

EGR is only an outside shale, speechless.

 

black smoke, low power, long cranking, engine won't stop, running for 4-6 seconds after turning the key. often lightly shaking. Changed 2 of 4 of timing valve for cll 4-5-6, as well of the shutoff valve. still doing the described symptoms. could be the injectors?. they were all ok before overhauling the engine.

 

You answer is in your question my friend, injectors... One or more injectors are leaking fuel in the cylinder causing it to run on like it does, especially for the amount of time your claiming its running on for, there is a way to try to figure out how to find which one is leaking, but depending on the mileage you have on the present injectors, it might be wise to go ahead with a six pack, while you treat yourself to an eight pack to change them lol Are these the original injectors to this motor even prior of the overhaul? and how long ago was the engine overhauled?

 

Does this sound related?