I'm lazy.
Is there some way to find out what zinc ppm is in these oils in question now without a lot of work?
I skimmed the article and I see a few API codes from 2006 and before.
API Oil Designation/Brand Year Zinc Phosphorous
SH 1996 0.130 0.120
SJ & SL 2001-04 0.110 0.100
SM 2005 0.087 0.080
Shell Rotella T 2006 0.140 0.130
Pennzoil 20W50 Racing 2006 0.196 0.180
I've got visions of buying a zinc additive.
Assuming it gives me the concentration in the bottle, I would have to do the math to figure out how much that would be in five quarts of oil.
And then I would have to know what was in my oil to begin with.
Sounds like work.
Actually, the only thing I'm really curious about is what oil do you use that you can say that you are using 1200ppm? (Out of the bottle?)
Is this on the containers somewhere. I've never looked.
I'd be surprised if the oil companies would tell us this.
STP says it has zinc.
I read the article's author as having some issue with the answer he got from STP.
(Follows)
What about STP
Oil Treatment?
STP (“Scientifically Treated
Petroleum”) is a well
known brand in the United
States with a long
automotive history.
The reference to ZDDP on
its label suggests that STP
(now owned by Clorox)
could be the most widely
distributed and the most
conveniently available additive.
Of STP’s Media Liaison/Technical
Advisor, OMC asked:
STP Oil Treatment claims on its label
that it ‘Contains ZDDP’, can you state
how much ZDDP is in your product?
STP Oil Treatment and STP 4 Cylinder
Oil Treatment contains 1 to 1.5% of the
ZDDP additive per bottle.
For clarification, if STP Oil Treatment
was to be added to 4 quarts of the standard
current grade SM engine oils,
which is regulated to 870 parts per million
ZDDP, can you tell me what the
overall ZDDP levels will be, and would
that level be safe for engines requiring
SE grade oils?
Response: Unfortunately, we do not have
that specification.
After this brief conversation speaking
with STP’s technical representative,
I regret to inform readers that I can
not endorse using STP (for ZDDP
additives) over other specialty products.
All motor oils have ZDDP, just the newer specifications call for less. There are no hard and fast rules here or magic limits as no one is doing the appropriate testing to see exactly how much is needed for an old engine. I have been using 1200ppm zddp oil (0.12%) on my 71 383 HP with flat tapper .484 lift cam and it has survived. anecdotal evidence, and some will claim that it needs 0.2% zddp. Will it last 100k miles? don't know, I drive daily and it is still chugging. SN rated oils like mobil 1 and GM dexos rated oils are fantastic lubricants for modern gasoline engines, have extended drain intervals...and have limited zddp so me personally would not use them in a flat tappet engine. you can use them and add zinc but my preference is having it pre-blended. again this is my opinion only, we all have to make our own choices.
Disclaimer: I'm not an expert. Here is a good in-a-nutshell guide to API ratings and oil for old engines. not too much marketing slant except I will say that there are other choices besides Amsoil and rotella T. API SJ and SL are the older specifications that are still in use by lubricant companies.
http://opelclub.com/ZDDP2.pdf