[quote=Chev Nut]
Zinc in motor reached a high point about 20 yeas ago with 1600 parts per million .Then it was reduced to 1200 PPM and then down to 800 PPM. The 800 is more than sufficent for 6 cylinder cars runing a well broken-in camshaft. Too much Zinc is also bad.
Gene,
I try not to over think the confusing subject of what oil is best, but any thoughts as to just how much zinc could be harmful ?
I bought a case of detergent 15W-40 Classic Car Motor Oil
http://www.classiccarmotoroil.com formulated for vintage engines with 1500 ppm as ZDDP. I was going to use this in my rebuilt 194 whenever it's done.
I see Lucas Oil has a 20W-50 detergent with a whopping 2100 ppm. Shell even has a high zinc product for classic cars, X-100, unknown ppm.
Maybe to be safe, just use the aforementioned 1500 ppm oil for a break in period,
then replace with something a little lower on the zinc scale ?
