Toasted Cam Shaft - Cummins ISX 870

It shows how fundamentally flawed oil sampling theory is - one of my mechanics told me he did camshaft replacement on a truck - well not exactly, Volvo it was - with about 350,000 miles on the motor and after that oil pump went due to pieces from the cam contaminating whole oil system. Now, when he does cams on ISX he insist on checking/replacing oil pump and roll the bearings. Yet there are still plenty people who keep oil for 36,000 miles and brag about it - like they are all bums from under the bridge who didn't eat in days. How can one own a truck yet can't afford $260 oil change - it really escapes me

 

If you cut the oil filter open and squeeze out the paper and find metal in it, on a warrenty covered engine they will tell you to replace the oil cooler and inspect main bearings 2 and 5. Checking the oil filter is something that is easier to do then an oil sample, the results are right there. Have seen lots of cams and rockers looking like the ones shown here, does seam to be a common issue. Would be a good time to inspect the rocker shafts for worn/oval jake detent holes, as they cause weak jakes when worn.
Also there is a new procedure to check the timing when reassembling that improves some performance but mostly helps with premature oil filter plugging, turbo sticking etc, but thats another subject...

 

So, whats th word about quality of materials used to make the cams ? Besides that they need good lubrication - they sure are not lasting like one could expect they would. I have two friends with Series60 who put 2.500.000 miles on their camshafts. What else could be at the root of the problem? And what is that new procedure about, do you mind to post something about it?

 

Not sure if the cam/follower failure are more common on the egr engines from the higher carbon content in the oil or if its just a hardsurfacing issue of the components. always have believed that the cleaner the oil the longer the eng life.
The new engine timing procdure for the 570/870/871 engines (twin cam) is that cummins found the timing can slowly move and it always goes to ######, which causes oil filter pluging, turbos to stick/carbon up, performance issues as well. So they now have a set up to check the timing where you pull #3 injector and measure #4 injector travel and check it to QSOL to see if its still in spec or requires adjustment. If adjustment is required they have new timing wedges for the injector cam that are in 0.25 degree incerments, so both cam gears need to be reset.(may take 4 to 5 hours). Drivers are saying that throttle response is better, increased fuel milage, way fewer regens etc. so it is good to see cummins doing something about this when most of these engines are off warrenty. so if you are having the top end open for any reason you might want to have it checked if you have had issues with oil filter, regens and turbos etc. just saying this is what we have found and hope it may help someone.

 

Because these cams aren't wearing out, they are crumbling. The pieces are to big to be suspended in the oil. Also is seems that when it starts happening , it happens very quickly.

 

we are having that issue with oil filters plugging, etc. but our company refuses to do anything, dont know if cummins is doing anything to help fleets out or what, but they arent trying to do anything about it. we have probably 2-300 trucks in our fleet that are doing this, mostly pb/kw with a few prostars, and I'm the 1 that brought it to their attention but they just keep changing oil filters, so I'm not worried about it if there not. have had several cams fail like above, and my personal opinion is too much soot in oil and too long of oil drain interval, they were running 50k oil drains with synthetic oil and around 350k the cam issues started showing up, so they went to dino oil and 36k oil drains. still having some problems still showing up from previous extended oil drains.

 

Thanks a lot for this info - here is another question: do you see a differences in cam wear between CM870 and CM871? I know there is much more soot involved in latter one thanks to increased level of EGR, more backpressure from clogged DPFs could be a factor too - but are CM870 any more resistant to the cams problem? Any other observations between those two generations? Also, which cam is more prone to wear and why?

 

With the isx injector cam wear ive been told its the low oil pressure operations common in isx my pressure at road speeds never hits 40 lbs hot and at idle at stop lights etc its 20 lbs, low compared to most engines, allthough mine made 1 mill 250,000 mile thats a lot of miles, but what is the norm for cams ?

 

The norm is that they go and its lubrication related. I'm at 970k and have 3 first, early scores on valve cam discovered at 955k. Cummins said come back in 20-30k to look at them again. That low oil pressure was on purpose, not sure what purpose was though. My dealer says they discovered lots of problems on ISX start with broken oil bypass valve - during cold starts oil pressure is so high it bypasses oil filter until it get down to working range but after so many cold starts the valve itself might quit working properly and you have no oil filtration and don't know it. Problem is, this guy really knows what he is talking about - they are top experts in my area