I was reading a magazine article the other day that stated zinc levels have been lowered in motor oil to help with pollution. The article stated that several aftermarket camshaft makers have seen elevated wear on their flat tappet cams because of this. The article also stated this was not a problem with newer OEM cars because all of them have swapped over to roller cams. It was also stated that using GM EOS (ENGINE OIL SUPPLEMENT) would fix the problem because it had a high zinc content. I would like to know what you think on this?
ZINC IN OIL
- Thread starter nova1970
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SM rated oil have lower zinc and phosphorus. There are several posts around here discussing this with differing opinions. If you are concerned about cam wear, use an API SL or SJ spec oil.
How would you know what kind of cams you have? Like, say, a 2005 Hyundai 1.6 DOHC?
Short of being an engineer? Because the owner's guide mentioned "SL or later" oil, I asked em that one a few weeks ago about the roller vs. flat tappets, and they looked at me like I was from Mars, or worse. I have given up asking ANYTHING of the service manager at the dealer, they know nothing of details about their own dammed product. It's uncanny. What are they, sworn to secrecy? Strange.
I oughtta ask him what a valve adjustment costs (they're hydraulically adjusted automatically).
Short of being an engineer? Because the owner's guide mentioned "SL or later" oil, I asked em that one a few weeks ago about the roller vs. flat tappets, and they looked at me like I was from Mars, or worse. I have given up asking ANYTHING of the service manager at the dealer, they know nothing of details about their own dammed product. It's uncanny. What are they, sworn to secrecy? Strange.
I oughtta ask him what a valve adjustment costs (they're hydraulically adjusted automatically).
Current Hyundais have DOHC valve trains with flat bucket-type hydraulic lifters. All the manure about accelerated cam lobe wear from reduced levels of ZDDP aside (the hysterics continue to intentionally ignore the compensatory elevated levels of molybdenum), you'll wear the tailight lenses out before you trash the camshafts.
It is not true that modern engines all use roller cams. LOTS of overhead cam engines still use a cam rolling over a flat "bucket" on top of the valve.The oils that removed the ZDDP zinc compound to preserve the catalytic converter are now usung substitute compounds in its place. I don't know if the new compounds are necessarily "worse" than ZDDP but they do cost a little more. You are probably very safe with the new oils.
If you want an oil with tons of anti-wear additives, try a diesel oil, like Delo 400. They generally have much higher levels of moly, zinc and phosphorus and are SL rated.
And that accelerated cam wear in engines that they talk about regarding reduced zinc is directly related to how "high performance" if you will, the valvetrain setup is. older muscle car V-8 engines and modern high performance solid lifter engines have higher valve spring rates and create much higher loads on the cam.
With my Toyota Corolla, or any other OEM non-roller setup? I bet you could push the valves open with your hand! I wouldn't worry about it. If you had yourself a small block chevy engine with a solid flat tappet cam that could rev to 7,000 rpms, then ya! SM/GF-4 would likely be a bad choice. But not for your run of the mill street engine.
With my Toyota Corolla, or any other OEM non-roller setup? I bet you could push the valves open with your hand! I wouldn't worry about it. If you had yourself a small block chevy engine with a solid flat tappet cam that could rev to 7,000 rpms, then ya! SM/GF-4 would likely be a bad choice. But not for your run of the mill street engine.
Drew99GT hit the nail on the head.
I see the guy who started the thread has a username of nova1970. If you have a high performance 1970 Nova with high valve spring pressure, it might behoove you to use diesel rated oil, as it has retained high levels of ZDDP.
I see the guy who started the thread has a username of nova1970. If you have a high performance 1970 Nova with high valve spring pressure, it might behoove you to use diesel rated oil, as it has retained high levels of ZDDP.
I don't think EOS is necessary when using a diesel rated oil, as they still have high levels of ZDDP. But it would make a good addition to an OTC SM dino.
MolaKule
Staff member
They are sworn to ignorance.
Nissan service writers are even worse.
Hey, come to think of it, MolaKule's SX-UP from Specialty Formulations would also be a good additive to make a SM oil compatible with muscle car engines
I'm surprised he didn't mention it.
I'm surprised he didn't mention it.
MolaKule
Staff member
Thanks Brons2, indeed it is.
In modern times, dealership employees only know what the manufacturer tells them, basically, with all due respect. They are there to keep things running smoothly and profitably, not quite the way it was 40 years ago when they all typically had been mechanics before moving into service management or writing repair orders. Some are better than others, though, just as in prior times. Very few "car people" left in the business, it seems.
If a manufacturer recommends a certain viscosity of motor oil, if you ask them "Why not something else?", they probably can't give a decent answer or can give one tinged with their own experiences . . . or worse, what some "expert" has said. Ask a rep for a motor oil manufacturer and you'll probably get a much better answer, even Too Much Information.
If a manufacturer recommends a certain viscosity of motor oil, if you ask them "Why not something else?", they probably can't give a decent answer or can give one tinged with their own experiences . . . or worse, what some "expert" has said. Ask a rep for a motor oil manufacturer and you'll probably get a much better answer, even Too Much Information.
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