Well, that's a whole other debate too I suppose - this one being about zinc and such...but ok, for the record:
My experiences with engine oil for lo these 6 decades above dirt was started like most - from what I was taught
young in life, which typically involved cars of the 50's-up - and they all were based on using multi-grade dino oil,
since that's what was around then.
My father, along with mechanic uncles and later on, garage owners I worked for in my teen years would only use
"straight weight" oil in higher mileage rides (the belief was it helped with oil consumption) - and of course, in most
anything industrial or agricultural, too.
Before the advent of synthetics, the debate seemed usually over detergent or non-detergent in those days;
as I recall, that was usually settled according to what the original engine supplier recommended.
That's a pattern I continue to this day on both auto engines originally designed with dino oil (my '68 GTX, for example)
and my ag stuff (like my tractor, which runs straight 30 wt. as recommended by the Japanese engine builder).
That said, I'm also a big proponent of synthetics - because I've SEEN what they can do when used in engines designed
for them (the first for me being the little "Shelby" 2.2 critters of the mid-80's, followed later by other rides including
a brand new 5.0 Mustang I bought in 1988). There was literally zero wear in those engines at 100k miles; heck, the
Ferd was at 250k when I sold it years later and the guys who bought it (to restore - imagine that!) were incredulous
at the condition of the drivetrain, even though it never had an easy day with me, pounding on it like I did for years.
Those engines were designed to take advantage of synthetics - and they did so with amazing results.
Nowadays, dozens of cars and a whole lot of years later, I've never had an engine failure where I've used the oil that
an engine was originally designed for.
Ever. Never ever.
The only engine failures I've ever either owned or witnessed all involved those older (60s-70s) engines like ours in
these cars where someone thought they were doing the engine a great service by using the "best" oil in it -
synthetic.
I've seen cams and/or lifters wiped in short order before my very eyes from this...
And I'll never make that mistake again.
So, current roll call time here:
- 2012 Charger 5.7 hemi - full synthetic from new, Hastings filter - 100k, zero issues
- 2004 Ram 5.7 hemi - full synthetic from new, Hastings or Mopar filter - 190k, no issues
- 2003 M-F (actually Iseki) 4wd diesel tractor - straight 30 wt., Iseki filter - 1400 hours, zero issues
- 1968 GTX with 440 number who knows, bought used - 484 purpleshaft + lifters - 15W-50 Driven oil + Hastings -
zero issues
This has all always worked for me; further, I've never experienced a case where it didn't.
Think I'll stick with what works, regardless of whatever "science" there might be to the contrary.