New Oil For Old Cars & Classic Cars
 

AMSOIL Z-ROD? Synthetic Motor Oil is specially engineered for classic and high-performance vehicles.
It features a high-zinc formulation to prevent wear on flat-tappet camshafts and other critical engine components,
along with a proprietary blend of rust and corrosion inhibitors for added protection during long-term storage.

Here's the 'rest of the story' with technical information so you can compare it to the 'competition'
10W-30 https://www.amsoil.com/storefront/zrt.aspx
20W-50 https://www.amsoil.com/storefront/zrf.aspx

Re: New Oil For Old Cars & Classic Cars
 

i know with my chevette we gotta use a zinc additive, usually orileys oil treatment like $3 with whatever conventional oil

model A theres a HUGE debate on what oil to use. the consensus is most people say ANY oil nowadays is 100X better than what they had back in the late 20's, alot run the same zinc additive with any 10-40W oil

Re: New Oil For Old Cars & Classic Cars
 

I've never heard of zinc additive requirements for older engines. How would I determine if my engine needs it? It seems ok on regular 10W30.

Re: New Oil For Old Cars & Classic Cars
 

70's and earlier?

Re: New Oil For Old Cars & Classic Cars
 

Zinc in the oil harms catalytic converters. Zinc used to be commonly used before emissions regulations hit in the mid 70's. Motorcycle oils still have Zinc though. Even if I had a car old enough to be able to use an oil with Zinc, I'd still use Mobil-1.

Re: New Oil For Old Cars & Classic Cars
 

And the blankety-blank exhaust valve seats will still recede, regardless of oil.

Re: New Oil For Old Cars & Classic Cars
 

they only recently took zddp (essentially zinc) out of oil like 5 years ago...

i know for a fact any chevette needs it (build 76-87) because of the flat tappets, without it the camshaft lobes wear down then ya need a new cam.

its not a matter of "if its able to use" zinc or not you NEED to use zinc or you WILL be replacing tappets or cams, if your car has flat tappets (usually older OHC or flathead guys) then ya need to use zinc.

the holy cow - find out if your engine has roller lifters or not, if it does then no need to worry (altho it cant hurt, your buicks were made when they still had zinc in em, just dump a $3 bottle of STP or Orileys oil treatment in, should list zinc or ZDDP or somehting as the first ingredient) i noticed once i dumped the bottle in and ran it to get it all mixed up good the car seemed to run happier and burn less oil (or leak i dunno hard to tell haha)

clencher - there are lead additives for gas to stop the exhaust seats from burning up :P if your car is old enough to need leaded gas tho haha that WILL clog a cat VERY fast


i see the EPA's reasoning for prolonging the life of cats but i dont think weve ever have one clog... they usually freakin broke (crumbled up inside) by themselves or rusted off...or we took them off...thats another bag o worms haha

i belive diesel oils also still have zinc but i think thats on its way out too...

Re: New Oil For Old Cars & Classic Cars
 

Holy Cow's Buick is not an OHC, its a pushrod V-6. I guess the reason I don't have problems in my older vehicles, is all of my older vehicles have V-type engines with pushrods instead of overhead cams. I don't think I've ever owned a vehicle with an OHC.

Re: New Oil For Old Cars & Classic Cars
 

Yup, I have pushrods and hydraulic flat tappets.

I did a bunch of googling, reading BITOG and other forums' threads on the issue, and came to this conclusion: There's no need to worry if you're using common oil in a stock engine. There may be specific engines where it's a concern even though it shouldn't be (such as those OHC Chevette engines), and for those you still may not need an additive.

If you have an aggressive camshaft, cheap aftermarket lifters bought during a time when supply was short (due to manufacturers going out of business and the others not taking up the slack), or are using weird oil, you should research the issue to see if you need an oil containing higher than normal ZDDP or an additive.

This is the most thorough writeup I found. It also has good research cited (at the end in fine print) and is written in language I was able to understand.
https://www.corvetteactioncenter.com/tech/oil/index.html
It's a long read but worth it. There's no fluff; it's a complex issue and you have to read it all.