Got zinc?

[G B.]

On page 62 of the March, 2006 "Car Craft" magazine, Jeff Smith dropped some disturbing news on owners of old performance cars. He said there have been some premature cam lobe failures in solid lifter engines because modern motor oils now lack a zinc additive that was previously common.

Jeff claims the oil additive was removed because zinc ash in the exhaust was fouling oxygen sensors and catalytic converters. He says running racing oil on the street might save a solid lifter cam because that oil is not formulated to meet modern emission standards.

Point #1: Yes, I know "Car Craft" has morphed into a humor magazine written BY children, FOR children. I read it for laughs, okay?

Point #2: Uh... I have noticed some pretty worn out cam lobes in the old engines I take apart. I wonder...

[Duke W.]

Re: Got zinc?

Using API service category CI-4 HD diesel engine oil will get you more ZDDP than spark ignition oils had 30 years ago. Modern SI oils (API SM) regardless of base stock - synthetic or mineral oil - have virtually eliminated ZDDP. Especially with aftermarket cams that require more spring force, modern SM oil, regardless of base stock (synthetic or mineral) could be a problem.

The whole synthetic - mineral oil argument is bull..., well, this is a family board, so I will say "moot".

Like I've been saying for nearly five years - ITAPS - it's the additive package, stupid!

Why do you think I keep harping about using CI-4 oil in vintage engines?

Bottom line: If you use OE design cams with OE spec valve springs and CI-4 oil, you need not worry.

Duke

[Jean C.]

Re: Got zinc?

Jerry, I had a look at the Chevron website and find that their motor oils for diesel contain zinc in varying amounts dependent upon the service for which the lube is intended. Also on the Chevron site, Texaco Havoline motor oil for gasoline engines contains zinc. If there has been a change to accomodate cat convertors, perhaps it is the amount of zinc that was changed, e.g. reduced. I am sure Duke will comment.

Best regards,
Charlie

[Scott Marzahl]

Re: Got zinc?

I usually use Kendall GT-1 because it does have one of the higher Zinc contents, at least according to their spec sheet as does Havoline. Am I reading those correctly Duke?

[Duke W.]

Re: Got zinc?

Brand doesn't mean jack. If the API service category is SL it has much less ZDDP than CI-4 and the new SM has even less than SL.

I use Chevron Delo 15W-40 (CI-4), and buy it by the case (six gallon jugs) at Costco. Delo is also available in 10W-30, but I've never seen it in stock in Southern California.

Don't use SM oil in a non-catalyst vintage car. If you have any remaining SL, go ahead and use it up, then switch to CI-4.

Duke

[Pieter Kanitz]

(Message Deleted by Poster)

Message Deleted by Poster

[Alan Drake]

Re: Got zinc?

First listen to Duke! The CI-4 will most likely be the best price, however if you still want another flavor;
try Valvoline,#205, VR1 Racing Oil 10W-30
or Valvoline, VV850, Racing Oil 10W-30.

[Clem Z.]

duke what is the difference in these 2 oils ?

mobil 1 API SM,SL/CF,1LASAC GF-4 and walmart syn oil, API SM/CF,1LSAC GF-4,ACEA A3,SL,SJ,SH,1LSAC GF-3 thanks

[Clem Z.]

just add a can of GMs EOS

which is high in zink. never use it in race engines after cam break in because the ash can cause piston burning.

[Duke W.]

Re: duke what is the difference in these 2 oils ?

API - American Petroleum Institute

ILASAC - International Lubricant Standardization and Approval Committee

ACEA (translated from, I think, French) Association of European Automobile Constructors

All three of these organizations promulgate various standards, including motor oil. The API is the oldest, and in the last ten or twenty years ILASAC and ACEA have promulgated their own standards. Most of the standards overlap and many motor oil manufacturers now cite all standards used worldwide.

The API has traditionally established oil performance specfications in consortium with North American auto manufacturers. A test suite must be passed to achieve API or other organization specs. The latest API spec for spark ignition engines is SM, but SL and SJ are still considered "current".

The lastest spec for four-stroke diesels is CI-4, but CH-4, CG-4, CF-4, CF-2, and CF are considered current. The CF standard goes back to 1984 and after that the diesel standard was split into four-stroke (-4) and two stroke (-2). The lastest two-stroke standard, CF-2, dates to 1994, and since two-stroke diesels have all but disappeared from automotive applications (cars, trucks, and off-highway equipment) it has not be updated. About the only two-strokes diesels I know of that are currently being produced are EMD locomotive engines, and they have their own oil specification.

For vintage spark ignition engines I recommend CI-4. For modern cars that don't specify a synthetic, SL or SM is okay, but I'm concerned about SM and may switch my older modern cars to CI-4. Of particular concern is the near elimination of the ZDDP antiwear additive from SM and lower viscosity grades to meet fuel economy standards. Modern engines have fewer sliding surfaces than vintage engines, so they need less ZDDP, and the combustion byproducts of ZDDP are believed to be a factor in catalyst degradation. But our vintage Corvette engines have lots of sliding surfaces like flat tappet cams and rocker balls. That's why CI-4 is better for vintage engines. The additional dose of ZDDP will protect sliding surfaces, and catalyst degradation is not an issue on pre-'75 cars.

If you have a modern car that requires a synthetic, follow the manufacturer's recommendation for oil specification. The modern specs like SM and GF-4 also have some "fuel efficiency" specifications, which is probably why I have not seen any 20W-50s at the store that meet SM.

Anyone seen a 20W-50 labeled SM?

The ILSAC GF-3 and GF-4 standards are probably roughly equivalent to API SL and SM, but I haven't studied the ACEA standards since I don't own a recent vintage European car. If you google on API, ILSAC, and ACEA, you can probably find as much information as you want including the complete test suites, standards, and chemical analysis specs.

If you've asked this question in the context of your C6, I'm not sure of the answer. GM has their own spec for modern Corvettes, and the only oil manufacturer I am aware of that has tested to the GM spec is Mobil with their Mobile One. That doesn't mean that other synthetics won't pass the GM spec. It probably just means they have not gone through the process of certified testing to the GM spec.

As far as your specific question is concerned, both of these products look the same as far as API and ILASAC are concerned. The Walmart product doesn't list the ACEA specs, which in the case of a non-European car doesn't mean much as North American and Japanese brands use API and ILSAC specs.

Duke

[Clem Z.]

i still use mobil 1 in the C-6

but i was checking to see if the walmart brand which cost 1/2 the cost of mobil 1 was a good oil to use in my 88 silverado which i have used mobil 1 for 130,000+ miles.

[Duke W.]

Re: i still use mobil 1 in the C-6

I doubt if your '88 Silverado calls for synthetic, but doesn't it have a flat tappet cam and rocker balls?

I'm switching my '88 Mercedes and '91 MR2 to CI-4 because I'm not comfortable with the additive package of SM. It's fine for new cars, but not necessarily vintage cars.

I don't need the longer life and better low temp flow of synthetic since both of these cars see only a couple of thousand miles a year in temperatures above 40F and they each get an annual oil and filter change before they go into storage as I swap them every six months - usually April and November. The Merc is my winter car and the MR2 is my summer car.

If the Silverado has lots of margin on emission testing (or doesn't need to be tested) and doesnt' have high oil consumption, I would use CI-4. It's available in both mineral oil and sythethic base.

Duke

[Paul L.]

Re: i still use mobil 1 in the C-6

Is 15W-40 GM GoodWrench oil CI-4? It is recommended for the DuraMax engine.

[John L.]

Re: Duke when you change to Cl-4

Duke, when you change to use the Cl-4 type oil is there a problem switching the type of oil if you have been running for years a conventional current oil?
Is it just a matter of switching oil or is there anyting involved? I mean you are putting diesel oil in a gas engine. I understand the additive package is richer for diesel over gas engines, am I reading too much into this?
Thanks for your input. John

[Clem Z.]

Re: i still use mobil 1 in the C-6

it has the flat tappet and rocker balls but it does set outside in the winter here,sometime to -10 degrees over night. it does not use much oil,i use 5W-30 mobil 1,about a quart in 3000-4000 miles. i change once a year,10,000-12,000 miles but i change the filter every 4000 miles. the inside the rocker cover looks like brand new looking thru the oil filler opening. i was just wondering if the walmart oil would be as good as mobil 1.