X15 overhead suprise

[ChickenHawk]

2350 x15, 348k miles, getting around to doing the first overhead adjustment. Found this little surprise waiting for me. Oil always changed at 15k, local work mostly interstate but some city driving. No damage to the roller, normal wear. Lobe for intake #1 just after the apex of the lift. Anyone ran into this before(edit: let me rephrase, is this the start of the signs of crankcase filter not allowing the pressure out, that I have read is common, atleast on the older versions)? Truck used to sit in winter time so some slight surface rust on engine brake rocker arms for front 4 cylinders. Valves were on tight side but not “out of spec” by Cummins standard. All the other lobes looked fine and rollers. Demandated but has been fixed.

   

[Rawze]

Yup ..

#1 - Cause of premature wear to the overhead cam is due to oil starvation on the top-end. Crank case filter not keeping up with venting crank case fumes well enough is the biggest culprit.

#2 - Bad delete that is causing accelerated valve seat wear .. Makes the rocker start to riding the cam all the time.. eats it up. - Accelerate wear can be check by measuring the clearances.

#3 - Bad install of (one or more of) the rocker shaft retaining bolts, allowing oil to get past them and starving the cam of oil pressure. This can be checked by running the engine with the valve cover off it.

NOTE: It almost looks like #3 might be the issue?, as that retaining bolt is not covering the hole all the way in that photo. I would be curious if oil comes streaming out from around that bolt if you cranked it with the valve cover off it. If it does, then that was the issue. If not,. then its one of the others mentioned.

Either way at this point, .. it needs a new overhead cam and rocker(s).

[ChickenHawk]

Thanks for the reply Rawze. Good eye, that is something I did not notice. That is the plan, new cam and rocker/s.