When I bought my '70 DH43N in 1975, we'd always used Gulf motor oil and gas, but by that time, the Gulf stations had changed to Chevron and I wasn't so sure about their motor oil. When I got the car, the Chry dealer had changed the oil. With stories of 'don't mix brands" running around, I asked what they used. Quaker State, I believe.
It had an issue with higher rpm. Just before it'd shift at WOT, it'd start surging. Checked carb, checked timing, etc. So I gave up. Then I decided to try some Castrol GTX in it, which many called "motorcycle oil", back then. With that ONE change, it'd pull hard to the shift and keep on going. Obviously, it was flowing smoother?
When I bought my '77 Camaro new, I asked the service manager what oil to use, when it got 1qt low at about 1500 miles. He said Pennzoil 20W (which we happened to have in stock). He said that that's what he used to run in his engines. So I added that. When it went through that quart in about 1000 miles, I was worried that I'd bought another Chevy "oil burner". So, I opted to go with Castrol GTX 20W-50 for that first oil change. Suddenly, it was only 1/2 qt down at 4000 miles. Which was consistent for a very long time.
When I replaced the intake (2bbl to 4bbl) and upgraded the cam (Cam Dynamics 266), I was shocked to see how clean it was inside. As were some other hot rodders in the building complex. Any accumulation in the lifter valley, in the small indentations, was very soft and liquid and only in those indentations. Very clean in that respect. On the underside of the intake manifold, on the heat crossover shield, very few deposits. Smaller than I'd ever seen in a 100K mile Chevy motor and also less than others in the complex had obviously seen, too (from their surprised comments). So I dosed the cam up with the moly paste, poured two cans of GM EOS (thick) over the valley and cam lobes. Costed the back of the cam sprocket with cam lube, as well as the chain before I put the front cover back on. That was at 92K miles with a new Cloyer Plus Roller timing chain set.
As the miles accumulated well past 200K, oil consumption eased up a bit. When it got to a qt every 4000 miles, the oil was still "not dark", so I'd add another quart and change it next time it got 1 qt low. When zddp issues happened, I upgraded to Castrol semi-syn and later to Rotella T 5W-40. Pulled it out at 525K, due to all of the freeze plugs seeping. Put a 355 short block. Same cam specs, but with '86 Corvette alum heads. Break-in oil was Valvoline 30W (installer
s choice). At the first change, I went back with 20W-50 and felt the throttle response edge go away. With 10W-40, it came back. Then went back with the Rotella 5W-40 and stayed with that.
During those decades, I was in my machine shop operatives shop daily. Never did see anything "fail" from oil issues. Wear issues, like valve guide/stem wear, with accumulations on the back side of the intake valve head chunking off on a long trip, or a valve stem eroded to where the head was about to break off, in one case! A Pontiac 400, I believe? But now crank wear that couldn't be polished out or with a .10/.10 undersize cut (to true-it up, too). .030" bore cut got it back to "fresh metal".
Back in the '80s, a guy brought in a Chevy 400 small block for a rebuild. Still had the factory hone marks on the cylinders at part 100K miles. Amsoil with their recommended change intervals. Back when it was an expensive and hard to find oil and FEW people used it.
Back when Chevy had their 427/430 crate motors, I sold the last one in existence. I found the installation instructions for it in the crate. Then looked at the motor oil they recommended for it. At that time, the OEM-spec oil was SM, which was about 800ppm zddp. High lift cam, heavy springs, as the original 427HO engine had. But they recommended SM oils for it! BUT, it had THEIR cam in it, which meant it had a thick enough layer of Parkerizing on it. It was also built "quickly" on their normal engine assembly lines, and they also ran it in on their dyno stands in the plant. So THEY knew how to do it, so was completely run-in for about 30 minutes before it was "hot tested" and crated. So it had a good start on life.
On my other laptop, I have a copy of their GM Powertrain engineering study on valve lifter "weight loss" when using SM oils on a flat-tappet camshaft. The decreased zddp levels did not cause any more lifter wear than normal, under that criteria. When they ran that test, they were still building small block Chevy flat-tappet crate motors and also flat-tappet V-6 replacement crate motors. BTAIM
I believe the Kendall motor oil brand is now owned by Phillips Petroleum? It's still around and was one of the first I saw to tout "Liquid Titanium" in its oil. Many Firestone service centers use it as their oil change oil.
Granted, current motor oil standards are driven by current OEM needs. Fuel economy, emissions, etc. Yet there are still some oils in the heavier viscosity ranges in these oils, too. So as always, use the viscosity applicable for your climate. There used to be some neat information in the back of the Mobil 1 website. Giving the zddp levels of their various motor oils. Similarly, in the back of the Exxon website was a USA map of what fuels were mandated for which areas of the nation, as a "minimum spec" sort of thing. Quite interesting as to how many variations there are! Obviously, more changes in the future!
Other than the decreased zddp levels, I believe that any modern motor oil is far superior to anything even dreamed of in later 1960s, when viscosity improvers began allowing 10W-60 "super oils" to be produced. And . . . the beat goes on . . .
CBODY67