[tirebird]

Since most of us don't care about the cold cranking or other cold weather tests, I thought the most interesting comparison posted in the AMSOIL test was the "four ball wear test". It's where, at high temperature and pressure, the scientists measure the wear on four ball bearings over a set period of time. Even with the new oil formulations without ZDDP, AMSOIL and Mobil 1 test pretty well.

Also, back in April, I wrote to Mobil 1 asking which of it's oils still had high levels of ZDDP. Here's it's response:

"Mobil1 MX4T 10W40 and Mobil1 V-TWIN 20W50 motorcycle motor oils, Mobil1
15W50 Extended performance and Mobil1 5W40 diesel motor oils contains
the higher levels of zinc and phosphorous for your cams. The new energy
conserving motor oils do have reduced levels of zinc/phos however, they
typically do not have any adverse effects on cams unless you are
running
higher valve spring pressures. I would suggest you stick with the
product listed above if you are concerned about the phos/zinc issues."