API oil service category update

[Duke W.]

This is just an FYI. It should not affect owners of vintage cars who are using the proper API service category oil.

API has replaced SM with SN, and this is done in conjuntion with an ILSAC update from GF-4 to GF-5.

S-category oils, SL and above, are NOT SUITABLE for vintage engines with sliding surface valve trains due to reduced anti-wear additive. Don't use S-category oil even if it's ten-buck a quart super-duper synthetic that the marketer claims will make your engine last a million miles.

Continue to use C-category oils in vintage engines. I'm not aware that the current CJ-4 spec that dates to 2007 is due to be replaced anytime soon.

If you're interested in all the bloody technical details on SN, you can start here:

http://www.api.org/certifications/en.../new/index.cfm

Duke

[Stuart F.]

Re: API oil service category update

Thanks for the info Duke.

Stu Fox

[Duke W.]

Re: API oil service category update

You're welcome!

ttt

[Ray G.]

Re: API oil service category update

Hello Duke;

Thank you for bringing pertinent information.

Ray

[Jack H.]

Re: API oil service category update

Duke.

Are there any additives in a Rotella CJ-4 over say a Walmart CJ-4 oil that make Rotella better for an engine with 125,000 miles?

[Duke W.]

Re: API oil service category update

No. As I emphasized in my engine oil article in the Summer 2008 Corvette Restorer, brand name is NOT IMPORTANT.

Just buy the least expensive CJ-4 you can find. That's what I do.

Private and "house" brands like Walmart's SuperTech are API certified C-category products produced by API certified blenders and are most likely a major brand purchased in bulk and retail packaged for the various private brands.

In order for ANY product to carry the API certification donut, it MUST be a formulation that meets the formulation specs and has passed all the API certification tests. Walmart and house brands don't have enough volume to blend and certify their own engine oil products, which is a multi-million dollar effort, so they just buy, in bulk, a certified product from a major manufacturer - which includes the big oil companies like Royal Dutch Shell, Exxon Mobile, and Chevron Texaco.

I don't understand why the people keep plugging Rotella. It's far from the only game in town. It's essentially the same formulation as any other C-category oil - no better, no worse.

Again, for the umpteenth time, brand is meaningless. The only thing that counts is the API certfication, PERIOD!

If anyone has any questions on this issue, I suggest you reread the article to refresh your knowledge.

Duke

[Michael J.]

Re: API oil service category update

I don't understand why the people keep plugging Rotella. It's far from the only game in town.
Duke

Agreed, I don't know about anyone else, but in my neck of the woods (high mountains of New Mexico), the only game in town is Rotella. I have looked at many auto suppy places within 50 miles, and the only CJ-4 they carry is Rotella. Last time, at a NAPA dealer, they had it in the back out of sight, they wouldn't even display it out front since it is so rare anyone wants it anymore, the guy at the desk looked at me like I was crazy when I asked for it. Other supply places could order other CJ-4s, but why wait? My WalMart has only one CJ-4, Rotella. I envy you guys that have dozens of CJ-4 choices in the big cities.

[Jim W.]

Re: API oil service category update

Thank you also. I'm wondering when the government will totally outlaw our Corvettes ? Motor Oil changes, Brake fluid changes, Paint, Tires, the treatment of nuts and bolts, Emission laws, what's next ?

[Stuart F.]

Re: API oil service category update

I buy the Rotella as well mainly because of it's availability both at Walmart and their warehouse "Sam's Club" affiliate. The Walmarts even carry it in quarts which are handy to have around for top ups in between changes (yes, old original engines do burn and leak a little).

Stu Fox

[John C.]

Re: API oil service category update

Thank you also. I'm wondering when the government will totally outlaw our Corvettes ? Motor Oil changes, Brake fluid changes, Paint, Tires, the treatment of nuts and bolts, Emission laws, what's next ?

Government has nothing to do with motor oil, something better comes along and the auto manufacturers adopt it. It's just progress.

[Paul Y.]

Re: API oil service category update

I bought Tech oil in the Wal Mart at Taos a couple of days ago.

[Duke W.]

Re: API oil service category update

Government has nothing to do with motor oil, something better comes along and the auto manufacturers adopt it. It's just progress.

...partially correct. The government has nothing directly to do with establishing engine oil standards, but are indirectly involved by demanding longer warrantees for emission control system performance including catalytic converters.

API establishes engine oil standards based on the needs of CURRENTLY PRODUCED ENGINES, few, if any, of which have sliding surface valve trains, so they don't need as much anti-wear additive; and phoshorous has been implicated as a possible cause of accelerated catalyst aging. Thus, less anti-wear additivie in current S-category oils than a decade ago, before SL went into effect, which was the first time P was limited.

The API membership includes all the big players in the automotive and petroleum industries, worldwide, and they are the folks who set the standards.

Even though most marketers claim that their current S-category oils are "backward compatible", that's a rather vague statement.

I believe one of the S-category anti-wear tests is done on an old Buick 3.8L V-6, but when those engines are no longer economical to maintain, they may be replaced with modern "roller everything" valve train engines, which means sliding surface valvetrain wear will not be tested.

As long as C-category oil retains the current level of ZDDP anti-wear additive, which is nearly equal to what it was before P limitations went into effect beginning with SL, we don't have to worry about finding readily available, reasonably priced engine oil for vintage engines with sliding surface valve trains.

Duke

[Michael J.]

Re: API oil service category update

I bought Tech oil in the Wal Mart at Taos a couple of days ago.

That's great, but since it is 80 miles from me, and gas is $4/gal., I doubt it is priced enough lower than Rotella to justify a trip

[William G.]

Re: API oil service category update

Greetings,

Hehhumm?? Question for Duke. So.........after reading your post above I went out today to buy my flat tappet cam 327 some oil.....and guess what? It is still confusing! The Rotella on my farm supply store shelf states on the API logo "Spec CJ-4/SM"! Now how can that be? CJ-4 with enough zinc or Phosphorus to protect the tappets AND still be acceptable for cat. converters? On the front it states "CJ-4" but on the back it states as noted above. Duke states "S-category oils are NOT suitable in sliding surface valve train engines", so how can the label state CJ-4 and SM both--it would seem to be one or the other? Duke, help me out, please. Thanks.

Bill

[John H.]

Re: API oil service category update

Greetings,

Hehhumm?? Question for Duke. So.........after reading your post above I went out today to buy my flat tappet cam 327 some oil.....and guess what? It is still confusing! The Rotella on my farm supply store shelf states on the API logo "Spec CJ-4/SM"! Now how can that be? CJ-4 with enough zinc or Phosphorus to protect the tappets AND still be acceptable for cat. converters? On the front it states "CJ-4" but on the back it states as noted above. Duke states "S-category oils are NOT suitable in sliding surface valve train engines", so how can the label state CJ-4 and SM both--it would seem to be one or the other? Duke, help me out, please. Thanks.

Bill

Bill -

I'm not Duke, but when multliple API service categories are shown, it's the first-listed one that matters.