Been a while since we've had an oil thread

[MikeSchinlaub]

Man, oil is a touchy subject, isn't it? I guess it's a good thing I'm not an engine nerd, just the regular kind!

 

[nola mike]

Guess you missed the part about better reduction in foaming and corrosion protection in humid environment

I must have missed that as well. The merc and Yamaha/Honda oils were on different ends of the spectrum for foaming, and also corrosion, and weren't great for shear stability. T4 did well on everything.

 

[Pmt133]

And still a worse performer on flat tappets. Go figure.

 

[Scott Danforth]

And still a worse performer on flat tappets. Go figure.

Where do you get that?

 

[tphoyt]

I was wait for this to blow up.

 

[nola mike]

Where do you get that?

He has another video breaking down that more zinc =/= better protection. I'm see if I can find it
Around 8:00

 

[Pmt133]

Where do you get that?

There was a white paper done a while back. Took a bunch of cams in, I think small block chevys. (Note lake cites this test constantly) and then run and put under a scope and wear and particle counts measured. The diesel oils constantly had ~double the wear rate vs even current API formulations at the time. My own testing indicates the same, diesel tends to show the worst performance in gas engines and it's kind of why API went and reformulated current oils for lower detergent levels, particularly calcium. Current formulations have more than enough zinc and lack of calcium to support flat tappet engines. I would still use a break in oil for a fresh break in, but the required film strength at the interface is strong enough to support any engines already out there, broken in, with them in it.

The higher detergent loading that isn't needed in a gas engine present in diesel oil competes with the zinc on the surfaces on a chemical level. The soot loading on diesels dispersed the calcium enough where it works as needed. It's functionally always been a chemistry problem.

Now is double the wear actually a problem when, even though you can measure it, we're talking about microns? No, not really. But it's been consistently demonstrated that dropping the calcium levels is much more effective then ridiculously high zinc levels. I had read the paper in college, can no longer find it.

Delvac and rotella sheared down to a thin 30wt in my 4.3 in the boat in under 50 hours. I'm also seeing chrome and aluminum from the rings and pistons in the samples now. Tried merc this go around to see what happens. While I expect it to shear, I suspect it didn't exhibit as great of a drop in viscosity. If I do see elevated wear metals in the oil again, then something else is going on and I can't blame the diesel oil.