[skyking]

Originally Posted by clarknova

I own some IDI engines and a common-rail. All of them have black oil, despite a disabled EGR and oil catch can. AMSoil sells a bypass oil filter that claims to remove soot and it's on my wish list.

We have a large mechanically-injected Cummins generator at work and the oil always looks pristine. I'm not sure what the secret is. Maybe because it never runs above 16% load except during semi-annual maintenance.

I drove a 2015 school bus with a Cummins 6.7 for two years and I never once saw the regen light turn on. Probably because I drove a rural route. I don't recall if the oil was black in that one.

The clean oil in the Cummins is a function of a properly broken in engine that is running a light fixed load. Throttling up/down for load induces more overfueling opportunities.
I worked as a deck engineer on a derrick crane that had a 350 Cummins for the hydraulics, and it was the same. At 250 hours it was a slightly darker amber color. It got throttled some, but the load was relatively light. The throttle applications were usually for just speeding up what you were doing at the moment.


In comparison, the 400 Cummins on the frictions had dark oil right after change, more the typical diesel pattern. It worked hard on a big load.


Ironically the 350 was swapped out for a Tier 4 Cat engine for an emissions credit with the feds. It had to be destroyed to get the $$ towards the Cat.
Here is the Cat in the same spot.


Here is a video of the 350 doing a little throttling, while picking up another crane off the bank and putting it on a barge. This is a largish derrick with 185' of boom and a nice 140 ton chart. The Bucyrus Erie 30B with boom and no counterweight was about an 85,000 pound pick at 65' radius.
https://youtu.be/2vJz6_Qr1BE