Oil ratings, API classifications and oil integrity

[33 IMP]

I was gifted a bunch of high-zinc SG racing oil, I think about 30 or 40 quarts. The trouble is its all crazy thick stuff, straight 50 weight. I'm using it anyway, a couple quarts at each change in my 440 bracket motor, along with 6 more quarts of 10/40 diesel.
(This stuff was originally used in a twin 454 racing ski boat)

 

[XS22J8R]

It seems to be widely reported in various places that motor oil has a "shelf life" and the "use by" date I usually hear is 5 years.
That is why I would be concerned about using a stash of older oil in my vintage cars.
Containers of oil don't have a expiration date printed on them, so it is hard to know for sure if the concerns over a shelf life are legit or an old wives tale that gets repeated. A chemist who worked at an oil company would have to chime in about if additives in the mix drop out or maybe their formulas break down over time.

 

[moparedtn]

I'd be at least passively curious if there's a settling out of additives in the bottom of a can...

 

[4speed68rt]

Its already millions of years old, so whats a few more decades going to matter...

 

[RemCharger]

Fwiw I asked my uncle who was a longtime chemical engineer for imperial oil (ExxonMobil esso, S-O ,whatever) and he felt there was no shelf life on oil.
We were discussing old cans

 

[Kern Dog]

I understand the suggestion to change the oil in our cars even once a year despite mileage. The engines are open to the atmosphere somewhat. The repeated cooling and warming cycles create condensation from the metal parts and that condensation builds up in the oil.
However...
Oil in a sealed container will not see the same condensation, especially if the bottles or cans are kept in a stable environment.

 

[moparedtn]

Well, crack one of those puppies open and let's see what's in there!

 

[The Capitan]

What about Arco Graphite?

 

[33 IMP]

Well, crack one of those puppies open and let's see what's in there!

I have used a couple quarts of my 30 year old 50wt, along with six qts of diesel, in my 440. Guess what it looked like?
Looked like perfectly fine, really heavy new oil. Nothing fell out of suspension that I could see, no residue in the bottom of the bottle. Last oil out of the bottle looked identical to the first.
I'm gonna keep on using it, a quart or two at a time, depending on the application. I used it to break in a solid flat tappet cam..... and I'm gonna do it again.

 

[Don Frelier]

I understand the suggestion to change the oil in our cars even once a year despite mileage. The engines are open to the atmosphere somewhat. The repeated cooling and warming cycles create condensation from the metal parts and that condensation builds up in the oil.
However...
Oil in a sealed container will not see the same condensation, especially if the bottles or cans are kept in a stable environment.

Changing at least once a year is suggested since the oil gets acidic after exposed to the gases in the crankcase.
I usually change mine in the fall run it enough to get it hot (at least 20 minutes of driving) and then shut it down and cap off the exhuast and carb opening for the winter.

 

[Darrah]

especially if the bottles or cans are kept in a stable environment.

And that right there is the key. My experience is more in the industrial maintenance world, where we've placed enormous emphasis on oil quality. For many applications, oil is required to be stored indoors in a controlled environment from the time it arrives on-site. Similarly, that brand new oil is filtered as it's added to the machine through a 2-stage filter cart and run in a kidney loop once installed. BUT... we're talking about extremely expensive gearboxes that keep machines making $20k+ an hour. For a car... if the oil was stored properly, I don't see the issue.

 

[70bigblockdodge]

The way I understand it is.
When manufacturers went to roller valvetrain components the need for as high of zinc (ZDDP) level decreased. With less zinc and demand for zinc in the oil helped to make the catalytic converter last longer, arguable because fuel metering with better fuel injection also would contribute. With less zinc the detergent package also changed helping the cat along. This is why I understand that adding zinc to new oil is not a good long term solution because the different detergent package will decline the zinc level over time.
I would not say newer oil is bad it is just not right for older cars and/or stiff valve springs on a flat tappet.
I do believe that tappet and cam failures are due to bad manufacturing, and not helped by oil.
The ZDDP provides a coating/insurance against low lube, high friction situations, like a lot of idling. I would use any of those oils and drive the crap out of the car, not idle around parking lot pimping with your lumpy cam.
That's my rant for today, your welcome.

 

[SlinktRR]

The SN classification is just newer API standards to keep up with the changes in the industry and extended drain intervals. I wouldn't use anything SN in a Mopar with flat tappets but the new formulations are far superior for your modern daily driver. I wouldn't use 30 year old oil in my new stroker but in my tired old 383, I probably would. If it's a motor you care about just get Gibbs.

 

[Eric Johnson]

I made an error. Almost half of the oil is SG rated.

View attachment 1575373

View attachment 1575374

Check these out… if nothing else, they’d be garage art.

View attachment 1575375

View attachment 1575376

View attachment 1575377

Most of the oil you have (SG or older) is "Garage Art" as you put it. SG was obsoleted by API in 1993. So, your engine oils are 30 years and older. Probably not suitable for any car due to age (additive dropout may have occurred among other things). Your Red Line oil you have in the first pictures has the API donut? If not, it is not licensed by API. The SN category was issued around 2011. There has been decreasing phosphorus levels in engine oils (ILSAC and API) for about 30 years now. There was a flat tappet test (Seq. IV) using a Nissan engine that is/was part of the subsequent oil classifications to ensure backward compatibility for engines using flat tappets. Most of the changes in the categories (ILSAC GF-5 and GF-6/API/dexos1) in the past few years have to do with LSPI (Low Speed Pre-Ignition) and Timing chain wear that can be a concern in Direct Injected (DI), Turbocharged engines. Hope this helps.

 

[Krooser]

Today I stumbled upon a small stash of UNused oil in bottles that had no date code on them but did have the SAE API circle with ratings of SD and SF.
I thought that I was told that the higher in the alphabet the second letter was, the higher the detergent level.
In short, an oil like this:

View attachment 1575278

View attachment 1575281

...with it's SN rating is a MUCH higher detergent oil.
If this is true, what other characteristics could be said about this older oil? Is it possible that it may have a higher Zinc count as well?
I ask because I suspect that as the oil market adjusted to meet new car emission standards, they also included roller lifters that didn't need the cushion effect that was crucial for flat tappet engines.
I have 20 quarts on unopened "classic" oil that have either the API SD, SF or no rating at all. The oldest oil that I got is in cans!

I don't intend to use this in my red car. I use "Driven" oil simply because of the stiffer valvesprings and solid lifter cam.
I have a few other lower performance flat tappet cars out back that may benefit from an older formula of oil. They do all have softer valvesprings which probably saves the lifters and camshaft from excessive wear.
What say you? Do you think the lower detergent oil may carry a higher amount of Zinc/ZDDP ? How would it even be determined without an oil analysis?

Several years ago I bought 80 cans of motor oil with the old SF rating.

Despite all the hand wringing some of my friends displayed about using this "old" oil I used as much as I liked in all of my various cars, trucks and machines.

My son's appropriated a lot of it so I likely only got to use 1/2 of it.

I thought it was funny that I was warned about using 30 year old oil that was made millions of years ago.

That newer bottled stuff will kill anything that needs zinc...

 

[Sixpactogo]

I don't believe there is a shelf life on oil. A Shell oil Guru once told me. "Oil don't ever break down. It only gets contaminated from use."
I have no idea about all the additives though.

 

[Kern Dog]

For the cars I have that I'd use this oil on, I doubt any damage could happen. They aren't daily commuter cars, they don't get raced. If they see 200 miles a year, that would be surprising.

 

[FASTEDDIE1960]

THIS was what I was after.
The part where you wrote "By Federal mandate, the arrival of SH spelled the end....."
THAT was what I suspected. It was because of that, that I suspected that this old oil could be better to use than the newer stuff in a flat tappet classic.
I didn't stumble into a dormant refinery...I only got 9 quarts of the Pennzoil and 9 of the Castrol, plus a few "cans" of stuff made before the API system was used.

the Pennzoil is good for Chainsaw chain lube

 

[Fury Fan]

I have no idea about all the additives though.

The additive package is *everything*" when it comes down to what the oil is intended for and capable of. (not picking at you Sixpactogo, I read thru this in one sitting and several other folks mentioned the additives also)

An oil guy I worked with years ago told me about mixing oil - if you know everything about both additive packs, and if they'll play well together - go ahead. They might not work well together, and you won't know that you're getting less protection than if either one was used alone.

There needs to be a whole website just about lubricants, where we could learn about them first-hand from industry insiders and experts.

 

[Photon440]

The additive package is *everything*" when it comes down to what the oil is intended for and capable of. (not picking at you Sixpactogo, I read thru this in one sitting and several other folks mentioned the additives also)

An oil guy I worked with years ago told me about mixing oil - if you know everything about both additive packs, and if they'll play well together - go ahead. They might not work well together, and you won't know that you're getting less protection than if either one was used alone.

There needs to be a whole website just about lubricants, where we could learn about them first-hand from industry insiders and experts.

There is such a site. https://bobistheoilguy.com/forums/