This is an update to the Torque Talk article in the July/Aug '07 issue titled "Newer Oils". As the earlier article outlines, beginning January, 2007, most engine oil has to meet new API standards with lower amounts of  zinc (Zn) and phosphorus (P) which are critical anti-wear ingredients required in engines with flat tappet (both hydraulic and solid non-roller) lifters. Most 90's and later engines have roller lifters and aren't as affected. Flat tappet engines with high-performance cams and higher than stock valve spring pressures are especially affected. The generally accepted minimum level of Zn and P for high performance flat tappet engines is .12%, or 1200 parts per million (ppm).  The new API standards for SM (gas engine) rated oils are .08%, or 800 ppm Zn and P maximum. The new CJ-4 rated diesel oil maximum is .10% or 1000 ppm.
  This topic has been the subject of much discussion on the Team Chevelle website. One member pursued the matter by corresponding with oil companies (usually without much cooperation) and finally went so far as to recently have some oil and additive samples tested by Blackstone Laboratory. The results are surprising and are listed below. Keep in mind the accepted minimum levels of P and Zn 1200 are ppm each.

* VALVOLINE NSL 20W-50 - (P) 842 PPM /(Zn) 973 PPM /(DETERGENT)950 PPM

* VALVOLINE VR1 20W-50 - 684 PPM/763 PPM/1630 PPM

* PENNZOIL GT 25W-50 - 1483 PPM/1676 PPM/1901 PPM

* GM EOS BLACK BOTTLE- 5059 PPM/5850 PPM/5,800 PPM

* AC DELCO EOS WHITE BOTTLE - 5183 PPM/6095 PPM/5,900 PPM

* STP 4CYL IN RED BOTTLE - 151 PPM/171 PPM/139 PPM (WAS 2115 PPM/3932 PPM IN 2005)

    The biggest surprise is that STP red can has been effectively eliminated as a suitable Zn and P additive. It's probably safe to assume that STP blue can has been changed for the worse as well. It's comforting to see that GM EOS still contains very high levels of Zn and P and can be added to regular oils to substantially raise the Zn and P to acceptable levels. The other surprise is the Valvoline oils tested which are both racing oils. Neither cuts the mustard but the Pennzoil GT 20W50 does. That's a synthetic racing oil and is a little pricey.
  The newer CJ-4 rated diesel oils still have an ALMOST acceptable level. Chevron Delo 400 15W40 in the good  CI-4 rating is still available at Autozone and some other stores. Per tests it contains enough Zn and P. Another solution to attaining a minimum of 1200 ppm of Zn and P is to use the newer CJ-4 rated  diesel oils with an appropriate amount of GM EOS Assembly Lube or other zinc-rich additive added. To calculate how much to add, refer to the chart at www.sterkel.org/avanti/documents/HowMuchAdditive.pdf. A stock Chevelle oil pan holds 4 quarts (both big and small block) plus one quart for the filter. Allowing approx 1/2 quart for additive, use 4.5 quarts for oil capacity. There are some other additives listed in another chart at that website. At this time the Team Chevelle member is having some more oils and additives tested. I'll report the results in a future issue. Meanwhile, don't roll the dice on newer oil. You could be sorry.

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