View original topic: Anyone ever run Royal purple engine oil? Page: Previous  1, 2, 3, 4  Next
bucko Thu Feb 21, 2008 7:05 pm

tencentlife wrote: Wel, Bob IS the Oil Guy, after all.

And you TENCENTLIFE for most everything else.

tristessa Thu Feb 21, 2008 7:23 pm

msinabottle wrote: STP red, which is officially known as 'STP 4 Cylinder Motor Oil Treatment' is MUCH cheaper and has more ZDDP in it. I've been looking for it at multiple FLAPS for some time, and haven't found it once. Still looking.
Look at a True Value hardware store. Some may carry it, any of them can order it (willing to is another issue); it's in all the distribution centers. Item number is 175-620, and since it's not an "f-pack" you shouldn't have to order an entire case. Might be able to find it at an Ace or Do It Best hardware store as well.

Disclaimer: I work for a True Value store, and just checked the catalog .. from home. On my day off, WTF is wrong with me? :lol:

tencentlife Thu Feb 21, 2008 8:11 pm

bucko wrote: tencentlife wrote: Wel, Bob IS the Oil Guy, after all.

And you TENCENTLIFE for most everything else.

Thanks, bucko, for the very kind words.

msinabottle Thu Feb 21, 2008 11:39 pm

That makes you a very thoughtful person, Tristessa, I haven't been checking the hardware stores. I only know of one TruValue left in the Denver area, but I can have a look at any of several ACE stores.

I'll keep checking and hunting... At least we're all aware of the problem and out to save our engines while there's time to do it.


tristessa Fri Feb 22, 2008 12:03 am

msinabottle wrote: I only know of one TruValue left in the Denver area, but I can have a look at any of several ACE stores.
The store locator at lists five stores near the 80001 zipcode, for whatever it's worth -- one of the "stores" listed for Portland carries a few odds & ends of paint supplies and miscellaneous stuff, but it's mostly a lumberyard.

There's a whole bunch of stuff I never would've thought to look for at a hardware store before I started working at one. :lol:

msinabottle Fri Feb 22, 2008 10:53 pm

Checker/Kragen/You're Nuts to Buy Parts Here had the STP Red 4-Cylinder Oil Treatment for $2.99 a bottle, I bought two. Not sure if a bottle of that will add sufficient ZDDP for Big Dodge, my '70 Dart's magnificent Slant 6, but it should take care of Winston.

The local Ace Hardware didn't have the STP. I walked over to the CarQuest across the lot... They didn't have the STP, but they did have BG MOA and BG RF-7, both of which mention that they reduce internal engine wear and cost 3x as much as the STP at Checker/Kragen/You're Nuts to Buy Parts Here.

Had a chat with a young mechanic at the CarQuest about how we're not very sure of how much of what is in those additives. He mentioned trying to get ahold of MSDS (I think that was the term) 'spill' sheets, that are used when a chemical spills to figure out cleaning techniques and to calculate hazards. That was clever, but I have no idea how to get those.

Data passed along as I stumble into it...


tristessa Sat Feb 23, 2008 9:44 am

MSDS is the Material Safety Data Sheet. They're available, but sometimes it takes a bit of calling & waiting to get them. Some manufacturers have them
available online, like the STP 4-Cylinder Oil Treatment MSDS at

Couldn't find one for the BG MOA at their website, might have to call 'em up to get it.

Perales Sat Feb 23, 2008 9:48 am

Manufacturers must, by law, provide MSDSs on request. Some will post them for easy access, but the have to provide them if you ask.

tristessa Sat Feb 23, 2008 10:01 am

Found the BG MOA MSDS online, but it's at a registration site and had to play some funky tricks to get it downloaded. Need someplace to host it, it's a PDF file....

tencentlife Sat Feb 23, 2008 12:59 pm

Once again, I can't stress sufficiently the need for people contemplating the use of oil additives to gain some education first regarding this complex issue. As a layperson, you can't do much better than to review Navarro's work to clarify the topic. Start here:

but please go on to read the entire article. By reading this far in this thread, you've already spent as much time as that would take.

I'll provide a little glossary for those who may get turned off by the plethora of acronyms in just that one FAQ answer:

ZDDP- we covered this.

GM EOS-GM's Engine Oil Supplement, which has been around forever, and gets taken off, relabelled, and put back on the market as often as I take out the compost.

TBN- Total Base Number. Base as in "basic", as vs. acidic. This is the number you really should be attending to. It is broadly a measure of the acid-buffering capability of the lubricant. It also represents, among other things, the level of potential detergency in the product. Oil tends to turn acidic as combustion byproducts, primarily carbon in gasoline motors but also sulfur in diesels, both of which are strongly acid-forming, dissolve in the oil. If the oil swings into acidic territory the wear surfaces will be chemically etched; not good. But if it is too actively detergent, the cleaning effects will also strip oil from wear surfaces where it should cling by viscosity; also very bad. TBN is a combined figure and essentially measures the ability of the product to deploy detergent effects in usable proportions without overwhelming and stripping the oil film, while neutralising acids as they accumulate in solution. Complicated enough for you? What do you think happens if you upset this delicate balance?

If you want to boil down TBN, though, you could look at it as an expression of how long the oil will be serviceable inside the motor. For racers, this matters very very little. For drivers who have bought into and adhere to the foolish and wasteful industry-promoted 3000mile oil change, it matters only a little. For fleet operators and drivers who take a more responsible approach to their lubrication schedules, it is paramount. Fleet operators do Used Oil Analyses regularly with samples from their vehicles, and although they are looking at many things as indicators of engine wear, most schedule oil changes when TBN reaches half of the levels they saw in the product's Virgin Oil Analysis.

TAN-Total Acid Number. The opposite of TBN. As TBN falls, TAN is going to go up.

I'm not presenting this as an advocate for any additive over another. If I were to advocate anything, it would be to reiterate Charles' assertion that you really should find a motor oil product that provides the anti-wear protection and long oil drain intervals we are looking for for this type of motor, at an affordable cost and with sufficient availability, and stick with it. Such products are available still, although the API's SM/CJ4 ratings change has narrowed the field considerably.

To begin that search, throw out any attachments you might have to using synth stocks over organic or vice versa. There is a reason that that is an unending argument that polarizes people, and the reason is that neither is definitively better than the other. When you see people become overtly passionate in their advocacy, whether it's oil, politics, or religion, that is generally a reliable sign that they haven't sufficient evidence to prove their point. So if your mind is made up that one is better than the other, that limits your choices. Get your mind un-made-up and your choices broaden. Then start looking at the things that actually matter much much more in your selection of oil for this type of motor: adequate but not extreme ZDDP levels, not less than 1100ppm but not more than 1600, and a high TBN.

If for some reason you're still convinced you need to boost your oil's anti-wear protection, then try to understand what you are doing.

I'll try to simplify the ZDDP vs. TBN relationship, if it will make that any easier. High levels of ZDDP deplete the TBN. So if you look at an additive and it has high ZDDP levels, you should also look at its detergency levels before you make a choice. If it doesn't add detergents at the same time, the boosted ZDDP in the additive will bring the all-important TBN down. This is OK for racing motors with very short oil drain intervals. It is not OK for road motors with long ODI's.

I'm not going to look at Product Data and MSDS sheets to make that analysis for anyone, so please don't ask my opinion, because my opinion is that you should study the choices, select a good oil product that has sufficient protections built in, and stick with it. It's also my opinion that you should do the environment, your motor and your pocketbook a favor and go to a 5000-7000 ODI, with a mid-period filter change and top-off for those with extra concern. So don't ask my opinion if you don't find those ideas appealing, because those are my opnions, and they travel as a pair.

For those who want to use one of the newer API-rated oil products, due to price and availability, and wish to boost its protection by the use of additives, I say it is doable, but here's my advice: when your favorite mechanic, best friend, or someone on this board says "I use this and haven't had any issues", ask them if they've ran 100k miles with that program and then done a teardown and inspection of their valvetrain and other engine internals. In the unlikely event that they have, given that the SM rating is less than 2 years old, and things held up well, their word is gold. If they haven't, run like hell. Then do the research and come to your own decisions.

tencentlife Sat Feb 23, 2008 1:15 pm

Oh, and the Royal Purple products that this thread was supposed to be about? Their products generally meet the required specifications, and are of very high quality. If you don't mind the price, or in some instances having to mail-order your motor oil (Pep Boys carries it in my market), you could hardly do any better.

Perales Sat Feb 23, 2008 1:38 pm

The more I read about ZDDP the more I understand that there are a complexity is issues related to it's use. Too little: engine damage, too much: cat damage, etc. I have decided that based on my reading I will supplement my oil to bring it up to a recommended ZDDP level but not higher. One of the problems is that adding a full bottle of ZDDPlus to an oil change will increase the levels way too high. For example one bottle of ZDDPlus to an oil change of Castrol GTX 20w50 will increase the ZDDP level to 0.27. Way higher than the levels of around 0.13 as recommended in earlier posts. A level of 0.27 will undoubtedly affect premature cat damage and modify the TBN more than necessary. Calculating the level changes by adding an additive to an oil is a bit fussy, so I have written an EXCEL spreadsheet calculator to make the calculation easier. You can try it by downloading it here if you want:

I made this for my own use but figure that if anyone else wants to try it, please be my guest. (although I assume no responsibility for it's use)

My goal is to achieve an ZDDP level of 0.13, which, based on my calculations can be acheved by adding about 1/4 of a bottle of ZDDPlus to an oil change of Castrol GTX 20w50. The good news is that this makes a product like ZDDPlus very economical as one bottle will serve four oil changes. The bad news is that it is hygroscopic and once the bottle has been opened it shouldn't be stored for any length of time. This suggests two options. 1) re-bottle it into smaller, one fl.oz. bottles and keep them sealed up tight, or 2) share with your friends. Get together with a few buddies to all change your oil and share a bottle to get to the correct levels. (Oh yeh, and split the ZDDPlus too :) ) Anyway, it becomes a very economical solution either way.

If I have completely missed the mark with this calculator, please let me know and I will remove it.

tristessa Sun Feb 24, 2008 10:23 am

I've read Charles' piece on the subject; it's good, recommended reading for sure. But this is a complicated subject, and the ground rules keep changing underneath us as oil formulations, additives and regulations are constantly being tinkered with. We need to keep ourselves informed.

Aside from the prospects of Information Overload and It's Too Much Work, it's not at all a bad thing to have the information available so that people can make their own informed choices about what to put in their engines. I'm not the type of person to take something as gospel just because there's a book, article or web page about the subject. And I'm sure I'm not the only one...

Mr. Electric Wizard Wed May 27, 2009 11:33 am

tencentlife wrote: Oh, and the Royal Purple products that this thread was supposed to be about? Their products generally meet the required specifications, and are of very high quality. If you don't mind the price, or in some instances having to mail-order your motor oil (Pep Boys carries it in my market), you could hardly do any better.

Does this still hold water?
I run Royal purple 10-30 in my Nissan, and I'm thinking about using 20-50 in my Vanagon.

jdbs3 Thu May 28, 2009 2:23 pm

1990 Vanagon GL

I've been reading with interest the various threads on oil, their zinc diethyl dithio phosphate (ZDP) content, and the importance of using such oil.

Possibly it says somewhere in my Bentley, or in one of these threads - Do all vanagons have flat tappet engines? Or more specifically, do 1990 vans have such engines?


tencentlife Thu May 28, 2009 3:10 pm

All the wbx engines, and the inline OHC engines, gas and diesel, are 2-valve, flat-tappet.

Mr. EW, that post was awhile ago, and things change, but RP markets to more of a racer/tuner crowd and seems less concerned with having the latest API standard, so they probably haven't dropped their ZDDP levels. Not using their products myself i wouldn't know, so to be sure you should contact them, or look up their product data sheets. Or look up your product at the BobistheOil VOA forums, or LN Engineering's oil page.

Wildthings Thu May 28, 2009 6:07 pm

Oils that have a W number of 15 or higher can be made with more zinc and still meet the SM standard, while oils with 0,5,10 W numbers (like 10W-30) can not. It is the GF-4 standard which really kills the zinc. An oil like Royal Purple does not meet SM specs at all, at least the bottles I looked at this past week didn't.

Here is a good link

As of 4/7/09 Mobil 1 Turbo Diesel and Mobile 1 15/40 still had 1200 and 1300 PPM zinc respectively. But I noticed just last week that the Mobil 1 Turbo Diesel oil was now labeled differently so I grabbed the oil stock from the back of the shelf when I bought it. The old stuff did not meet SM standard while the new did. :cry:

badgerb0b Fri May 29, 2009 1:35 pm

Since I cannot find Royal Purple where I live.

Redline 10w-40 looks like it is well suited to flat 4's with lots of ZDDP.

Has anyone used this stuff before?

you Fri Jun 05, 2009 6:38 am

just a heads up for yall.....pepboys has discontinued sales of rp 15w-40 and is selling it at $4/qt....ive been trying to find a more recent analysis than charles' at ln but with no luck...emailed rp last night and they were very prompt with the replies, but wouldnt discuss the blending or packages since its proprietary, also didnt provide an msds...david stated that ci-4 zinc content is capped at 1300ppm but should not be the deciding factor for wear protection, its all in the package, but if your looking for more zinc out of their lineup the xpr has 1600ppm zn

Mr. Electric Wizard Fri Jun 05, 2009 6:45 am

I ended up buying a case of Brad Penn 20W50 partial synthetic (all their oil is partial).
I should be good to go, after all, it's green. :D

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