Due to the many misconceptions for the need for 1600ppm of ZDDP (Zinc Dialkyl Dithio Phosphate) in motor oil, Collector Automobile Motor Oil has produced this fact sheet. Each statement lists the location of the source of information.

November 2007 Technical Bulletin: TB #2333R

The current engine oils used by engine manufacturers in new car production are not applicable for initial flat tappet camshaft break-in. Those newer oils are less desirable than older formulations which have better wear additives than the current SM category oils. With the advent of roller lifters/cams as well as roller rockers, the need for those expensive elements has diminished. Emission laws have caused the reduction of Zinc and Phosphorus in the current oils because as they pass through the exhaust they plate themselves to the inside of the catalytic converter. This plating action does not create a restriction or increase back pressure but it renders the function of the catalytic converter useless. Eventually, this non function will turn on a check engine light for emissions failure. Numerous AERA (American Engine Rebuilder's Association) members report premature flat tappet camshaft failure during or after break-in.

The full report is located at: Oregon Engine Rebuilders website.

Subject: Flat Tappet Camshaft Failures (Hydraulic & Solid/ Mechanical) 1/29/10: Recent changes in oil and engine technology are likely the cause of premature camshaft failure.

COMP Research & Development Tech Bulletin...

November 2008

The lower ZDDP content is not harmful to late model engines with roller lifters or followers because the loads are much lower on the camshaft lobes. But on push rod engines with flat tappet cams, the level of ZDDP may be inadequate to prevent cam lobe and lifter wear. In some cases, cam failures have occurred in as little as a few thousand miles of driving! This is even more of a risk in engines if stiffer valve springs and/or higher lift rocker arms are used.

AA1CAR.Com page2 para2...

January 2008

I have a new 460 bbf I put $7,000.00 into and no zddp in my oil wiped out my camshaft. I spoke to Comp Cam reps and they said per battem: "WE HIGHLY recommend using VR1 racing oil it has a high particulate count of zddp. Also said we DO NOT RECOMMEND SYNTHENTIC OR SYNTIC-BLEND in flat tappet applications. Reason being synthetic does not allow the lifters to properly travel the surface of the camshaft lobe." This is from a rep at Comp Cams. Who also builds race motors for the last 20 yrs. P.S. my oil pressure never dropped and I used synthetic blend oil, and I had 7000 miles on the motor.

September 2009

Why can't we use Racing Oils?

There are some racing oils which maintain a level of ZDDP. Racing Oils are optimized for short term severe duty, in contrast to an oil that has been designed for day in, day out street operation. The additive package in a racing oil does not have the same detergent characteristics which are designed into extended service oils. As a result, racing oil may not have the capability of neutralizing acids and keeping contaminates in suspension. Also, the breadth of choice of viscosity, so important to correct street engine operation over a broad temperature range, is not available in racing oils. Visit the ZDDPlus website for more information...

February 2011

Unfortunately Castrol's oils formulations are proprietary information and are not released to the general public. However, we can tell you that the ZDDP levels have been reduced. We DO NOT recommend any of our GTX Dino oils for flat-tappet engines….
Castrol Consumer Relations

I called them to confirm this. They do not recommend any of their dino oils, (including 20w50 and 15w40 Diesel) for our air-cooled engines (or any engine with flat tappets).

February 2010

At the time, we presented a few long-term solutions that included certain off-the-shelf products, among them commercial-grade oil, and General Motors / Engine Oil Supplement (E.O.S.). All the well until we learned that most 2007 diesel engines were gaining an exhaust system catalyst, which likely meant oil reformulation, and that GM discontinued its highly-concentrated E.O.S. product-two serious blows that struck panic into the hearts of hobbyists who relied so heavily on these products.

November 2009

GM Engine Oil Supplement –EOS-Engine Assembly Lube-16 oz.

Detailed Description:

  • Specifically formulated as an engine assembly lubricant. EOS provides outstanding protection against run-in wear and piston scuffing as well as run-in camshaft lobe and lifter scuffing resulting from insufficient lubrication.
  • Contains concentrated friction fighting and anti-scuffing agents.
  • Use on all engine bearings cams and reciprocating parts.
  • Helps prevent scuffing of newly assembled components.
  • To be use as an assembly lube, not an oil additive.