Re: Zddp question

Posted by su8overdrive On 2022/9/29 13:46:30
Dear Icarus! Thou art soaring too close to the incessant glare of the bolshoi. Heed JW, Tim Cole, Fish'n'Jim. Let the facts in attendance always be seated before hearsay.

We'd thought the ZDDP business long since vanquished by stake through heart.

The below is from a post made several years ago after discussion with major oil company techs, themselves owning various flat cam engines, one relating that he'd also owned a '41 Packard.

But first, everything from Packard's publications through MoToR's Auto Repair Manuals of the '30s, '40s, '50s lists 20W winter, 30 summer for Packards, and for nearly all other cars.

20W/50 is better suited for a worn out engine flogged in Arizona. Its thickness prevents it reaching all the critical metal-to-metal wear spots on cold start up.

Herewith, sir:

ZDDP/zinc is a another red herring. Today's zinc levels were "lowered" back to where they were in the '70s and before, after too much zinc hindered catalytic convertors. And we didn't hear all this zinc hysteria back then. You can trace it to a couple curmudgeons in the CCCA with flathead Cad 346-ci V-8s which use, unlike Packard's hardened steel, a chintzy bronze timing gear. They had trouble after rebuilds, so of course, it's the motor oil. Some Joe Sixpaks w/ the usual backyard hot-rodded SBC 350s had problems after their rebuilds, and also blamed the motor oil. The internet can be akin to shouting fire in a crowded theater or Fox "News."

Let's try some vetted journalism, engineering savvy.
"Just the facts, ma'am."

A Kendall/Conoco-Phillips engineer, himself with a highly-tweaked '67 Camaro with -- like many of our Packard engines (the big '30s seniors had the quality of a roller cam, but then even Packard/R-R Merlins have flat cams)-- a flat cam engine with m u c h higher valve spring pressures, explained that a friend of his was the one who produced the Indiana Region of the CCCA's 15W/40 "Classic Car Motor Oil," (advertised in Hemmings, etc.) and that even Kendall started marketing some oil with higher zinc because, he laughed,

"If you want to stay in business, you either give people what they want or think they need."

This petroleum engineer and gearhead himself uses the same off-the-shelf Kendall GT1 10W-30 i use in my '47 Super Clipper's inline eight lawnmower engine. I use Kendall because i came of age on the East Coast, liked the smell and old color (since abandoned), akin to Packard engine green, being a sucker for marketing, but an exhaustive Consumer Reports feature compared various major brand motor oils of the same weight used 60,000 miles in a fleet of NYC cabs and found little or no discernible difference among any of them.

ZDDP additives only settle at the bottom of your sump. And too much zinc unleashes other woes:

Much ado about naught. The cheapest off-brand motor oil available today streets ahead of the best from the '60s, let alone the '40s. By extension, a Chevron or ExxonMobil petroleum engineer explained to a lifelong auto/aero machinist/mechanic pilot supercharged '37 Cord Phaeton, Auburn 12/Marmon 16-owning friend that the black molybdenum/graphite chassis grease, whether those brands or Sta-Lube, a factor of eight times better than the orange fiber grease around when our cars new into the '70s. And that exchange was in the late 1970s/1980.

Finally, and pardon the verbiage but not being retired as many here gathered, when i do post include what i can, thrice annual oil changes, certainly at 2,000 miles, are excessive and pointless, given the superiority of modern detergent motor oils, providing the owner not make the common mistake of firing up his car in the garage to show it off for a few minutes to visitors, then letting it sit for weeks or months.

Never start an engine lest you intend to drive it at least 18 or so miles highway to equalize temperature of block, manifold, head, stave off the formation of sludge, varnish, carbonic acid. A local fire dept. used to fast idle their trucks for 15-20 minutes then shut them off, only to discover they were only wearing their rings.

An old mechanic's test was to place your hand on the bottom of your oil pan. If too hot to keep there more than a split second, you got your oil hot enough.

I like a stone simple device provided by, which captures your engine's peak oil pressure in an aluminum cylinder, which you can release via hidden toggle to pressurize your engine before starting, when according to McDonnell Douglas, Continental, and the SAE, 80-90% of all engine wear occurs.
Tell Kerry McCracken a '47 Super Clipper in Walnut Creek,CA and a quartet of '50s Ferraris near me referred you.

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