Originally Posted by racin4ds
Originally Posted by ofelas
One valve cover lets you access both camshafts?
Me thinks he was being facetious...
Yes. I was speaking of my DD13 which is a straight 6 with overhead cams and a one piece valve cover.
And yes, I was being silly about swapping out the cams at each oil change. I saw this thread and "bit my tongue" for a few days but today I couldn't resist. My Detroit has over 400k miles on it now, with the last 317k miles running with Chevron's CK-4/SN oils. I recently finished another 58k mile OCI with Delo XLE. I will update my UOA thread when I get my results on the last OCI.
The OP mentioned that he's using CI-4 oil that has all that wonderful phosphorus and zinc. Back in the days of CI-4 oils, I was trying to get close to 30k miles (was using 4000 gallons of fuel as my determining factor) between drains. During my summer time OCIs the hard work would thicken the 15W-40 viscosity into the 17-18 cSt range at 100C. Now I'm getting 55k-58k miles without breaking a sweat.
Twenty years ago, one million miles without an overhaul (speaking of heavy duty diesels) was a decent target. Since CJ-4 came along (around 2006 if my memory serves me right), one million miles is nothing. Obviously, there are plenty of issues that can mess that up; bad metallurgy, losing coolant and overheating, driver errors, etc. The point is, the oils may look different on our VOAs and UOAs now, but the formulations are clearly working well. The tests required to pass CK-4 are tougher than the previous categories and the engine manufacturer's related tests are tougher yet. There's obviously more to an oil than what we see on paper.
CK-4 provides improved shear stability, oxidation stability, better control of aeration, and maintains cold weather properties longer. That's all good to me.