No, this thread can't die.........
So I found that elusive technical paper from SAE but it just says to make an engine study.
Now I search for the newest SAE "study; laboratory engine test".
SAE technical paper below.
Cam and Lifter Wear as Affected by Engine Oil ZDP Concentration and Type
1977-02-01
Technical Paper
770087
Loren G. Pless, John J. Rodgers
The recent increase in excessive camshaft and lifter wear after extended service has shown that some SE-quality engine oils do not provide adequate protection. To determine the effects of oil additives on wear, controlled tests were run using 1972-1974 model cars, unleaded gasoline, and either SE commercial products or experimental formulations. Field experience with 1970-1975 model trucks, leaded gasoline, and SE/CC or SE/CD oils was also investigated. With some commercial oils, in both controlled tests and field experience, excessive wear sometimes occurred after extended service, even with recommended oil-change intervals. Generally, protection from excessive wear was best provided by those oils containing pre-dominantly alkyl ZDP (zinc dithiophosphate) antiwear additive instead of aryl ZDP. These results show that a laboratory engine test is needed to evaluate the long-term wear protection of engine oils.
I know it is from 1977, so what if it only took me three weeks to find a 38 year old comment?
I have a 46 year old truck. Maybe one day I'll catch up and watch color movies too.