I was cruising around looking to see if I could find the ZDDP level in the Suzuki branded oil, and I found this good explanation of what ZDDP is and what it does.  It is absolutely necessary that you use an oil with a high (1,200 - 1,400 ppm) level of ZDDP if you want your cam and rockers to survive.

ZDDP is a single polar molecule that is attracted to Iron based metals. The one polar end tends to “Stand” the molecule up on the metal surface that it is bonded to by heat and friction. This forms a sacrificial layer to protect the base metal of the cam and tappet from contacting each other. Only at very high pressures on a flat tappet cam is this necessary because the oil is squeezed/wiped from the surface. This high pressure is also present on the gudgeon pin (wrist pin) in diesel engines, therefore the need for ZDDP in diesel engines.
Second part of the equation is Molybdenum disulfide (Moly). The moly bonds to the zinc adding an additional, very slippery, sacrificial layer to the metal. I found out that too much of the moly will create problems; lack of this material reduces the effectiveness of the ZDDP. The percentage, by weight is from .01 to .02%, not much, but necessary.

Dave wrote on 10/14/15 at 04:02:56:


Thanks