I run Mobil 1 or Mopar filters and use Rotella T 10w30 diesel oil. The diesel oils still have the zinc and phosphorus the flat tappet design engine needs, modern oils/gas engine oils do not have the additives. I did a TON of research on what oil to use and after many, many articles it looked like the common choice was Rotella T in 10W30.
Here is an article from Hotrod magazine regarding flat tappet cams:
Around the time of the flat-tappet lifter shortage, motor oil was experiencing its own changes. Engines with flat-tappet cams have extremely high pressure loading at the contact point between the liftercrown and the cam lobe. According to Mark Ferner, team leader for QuakerState Motor Oil Research and Development, "Even stock passenger cars can see pressure in excess of 200,000 psi at the point of flat-tappet/camlobe contact." To prevent excess wear, traditional motor oil included a generous dose of antiwear additives, primarily zinc dialkyldithiophosphate (ZDDP). "The chemistry is such that the additive is a combination of zinc and phosphorous," says Rockett Racing Fuel's TimWusz. "Typically the phosphate amounts are about 75 percent of the zincamounts. For example, if there was 0.100 percent zinc by weight in the motor oil, then the phosphate is about 0.075."
Ferner adds, "The zincreacts with the cam lobe's iron surface. That creates a sacrificial chemical coating strong enough to keep parts separated to reduce the wear." Although great for keeping a flat tappet alive, as an engine ages and develops blow-by, some of the additives flow out the exhaust where they can degrade oxygen sensor and catalytic converter performance.Faced with ever more stringent emissions standards and the governmental mandate for extended emissions-control- system warranties, the OEMs got together with the motor oil makers and decided to reduce the amount of ZDDP in street-legal, gasoline-engine motor oils. After all, they weren't needed with modern roller lifters and overhead-cam followers.The reduction first started in the mid-'80s, and it has been a gradual process, but the latest API SM and GF-4 specs have reduced ZDDP content to such an extent that the new oils may not provide adequate protection for older, flat-tappet-equipped vehicles running non stock, performance cams and valvetrains. And it will only get worse; projected future oil spec revisions will likely reduce ZDDP content even more.
And here is an email from Shell regarding Rotella T being used in flat tappet designs:
The reply from Shell:
Hello Paul,
Yes, diesel engine oils like Rotella T are also rated for gasoline
engines and have additional anti-wear additives at a content level that
is comparable to the level that passenger car motor oils had in 2000
before the current problems with flat tappet engines began. Gasoline
engine oils are currently at a level of about 800 ppm zinc.
See the link below for more information about Rotella.
http://www.shell.com/home/Framework?siteId=rotella-en&FC2=/rotella-en/ht
ml/iwgen/press_release_2006/zzz_lhn.html&FC3=/rotella-en/html/iwgen/pres
s_release_2006/cj-4_triple_1006.html
"Rotella w/ Triple Protection" meets API CJ-4, CI-4 PLUS, CI-4, CH-4,
CG-4, CF-4 for diesel and
API SM, SL, SJ, SH for gasoline engines. A data sheet may be found at
the following link:
http://www.shellusserver.com/products/pdf/RotellaT(CJ-4).pdf
For more information about the API classifications, you may want to take
a look the following link to API:
http://www.api.org/certifications/engineoil/categories/upload/EngineOilGuide2006.pdf
If you have any additional questions, please call us at 800-231-6950.
Thank you for your interest in Shell products.
Thanks for your email!
Regards,
Keith Perry
Technical Information Center
Customer Service: (800) 840-5737
Technical Support: (800) 231-6950
