Camshaft failure Cummins isx15

[RichHomie27]

Replacing camshaft and 12 rockers due to scarring cam and rockers, was some metal shavings under valve cover obviously. Mechanic is going to check mains and rods, and take an oil sample and do PM service.. is there anything else needs to be done? Do I HAVE to change oil cooler?

[Rawze]

Maybe find out why are the rockers got chewed up?..

If they have more than a million+ on them ok.. but otherwise... something caused it.

#1 cause = Neglect of the crank case filter.. and allowing crank case fumes to build up in the engine and starving the top end.

#2 cause = some fool not doing oil changes based on fuel mileage and going too long between changes. Oil changes should be based on this chart...
http://rawze.com/forums/showthread.php?t...9#pid76569

#3 cause.. some fool using synthetic oil in the engine .. and then not doing oil changes but every 28- 30k mile or more intervals.. or relying like an idiot on oil sampling and bypass filters garbage that these engine killing XM radio shows try to tell people to do.

#4 cause .. excessive blo-by and the crank case circuit cannot keep up with the fumes building up any more... allowing pressure to build inside engine, starving the top end of oil.

#5 ... no one ever adjusting the overhead valves every 2 years or 250k miles like they should... and the rockers are riding the cams all the time.


take your pick.

[RichHomie27]

(08-01-2023 )Rawze Wrote:  Maybe find out why are the rockers got chewed up?..

If they have more than a million+ on them ok.. but otherwise... something caused it.

#1 cause = Neglect of the crank case filter.. and allowing crank case fumes to build up in the engine and starving the top end.

#2 cause = some fool not doing oil changes based on fuel mileage and going too long between changes. Oil changes should be based on this chart...
http://rawze.com/forums/showthread.php?t...9#pid76569

#3 cause.. some fool using synthetic oil in the engine .. and then not doing oil changes but every 28- 30k mile or more intervals.. or relying like an idiot on oil sampling and bypass filters garbage that these engine killing XM radio shows try to tell people to do.

#4 cause .. excessive blo-by and the crank case circuit cannot keep up with the fumes building up any more... allowing pressure to build inside engine, starving the top end of oil.

#5 ... no one ever adjusting the overhead valves every 2 years or 250k miles like they should... and the rockers are riding the cams all the time.


take your pick.

I had to replace camshaft due to ticking noise back in February, when mechanic did this he replaced the camshaft and only ONE rocker. 3 months later I come back due to a knocking/clunking noise and it ended up being 2 more rockers, so he replaced those 2. Now once again I’m back bc same knocking/ ticking noise. So new mechanic says it’s due to not replacing the 12 rockers at once the first time I got new camshaft. I take care of my truck pretty good I would say, since the short time having it. I don’t do oil changes to to often bc I haul sand. So it takes me awhile to even just put 10-15k miles on my truck, but maybe I should stop going by miles and maybe go by engine hours bc my APU has been out for awhile so I do IDLE. I try to do oil change on average every 15k I would say but it can take me time especially if work is slow to even hit that 15k+!
Oh and last time I got the 2 rockers replaced, old mechanic I was dealing with did use a Mystik Synthetic Blend oil when I did PM. Before I always tried to use Mobil Delvac.

I do have minor blow by. At 693k miles now. Besides this issue engines runs really strong, never lose oil pressure. And blow by hasn’t gotten any worse the last 60k miles.

[tree98]

If your rockers are worn out, so are you rocker shafts. Make sure those get replaced along with all the rockers and both cams. 693K isn't very many miles to have worn out rockers and cams. Maybe it's from all the idling at a low oil pressure.

[RichHomie27]

(08-02-2023 )tree98 Wrote:  If your rockers are worn out, so are you rocker shafts. Make sure those get replaced along with all the rockers and both cams. 693K isn't very many miles to have worn out rockers and cams. Maybe it's from all the idling at a low oil pressure.

Only have a single cam Cummins.. but yeah I didn’t know its good to idle at high rpms til about a month or 2 ago. So I’ve been doing that. And rocker shafts?

[RollinCoal]

Sounds like someone didnt adjust the valves properly on the first repair

[RichHomie27]

(08-03-2023 )RollinCoal Wrote:  Sounds like someone didnt adjust the valves properly on the first repair

believe it or not the second time i went to get the 2 new rockers they put it back together and sure did forget to adjust the valves, i noticed cuz truck was making same noise when i went to pick it up. and mechanic said " you know we forgot to adjust the valves come back tomorrow to pick it up".

[RollinCoal]

Might want to look around for a different shop, I mean its 2nd nature to me if I remove the rack they get checked on install at the least

[JimT]

have you checked/rebuilt your fuel pump head? you didn't mention exactly which engine, but if there's only one cam then you have a common rail with the high pressure pump that is subject to failure, usually around the 400-450k mile mark (or equivalent hours in your case). They are known for sending ceramic (on the original ones) or metal debris into the oil and through the engine. chewed up cams are a common result. Plenty of info about them on this forum if you search.