Originally Posted By: junebug
I studied this ZDDP issue about 6 months ago. I have a 1979 Chrysler slant six 225 flat tappet engine. I'm of the opinion that ZDDP is beneficial in these older engines,esp. ones with "heavy"(ie iron,not aluminum),valve trains,higher spring pressure,and mechanical lifters. The STP red bottle has more zinc than the blue.I think it is being dicontinued,but there is still some around. SLOB is probably all gone from Big Lots.GM ENGINE OIL SUPPLEMENT is an option,but is $10. a pint.If it's not necessary, why does Crane and others recommend it when installing a camshaft? 99% of people do not drive a 30 year old car,and do not seem to understand our dilema.Hope this helps.THX.
Back when I was doing the cam change game, I talked with some local tweaks, and one engine builder. Some used STP, and GM's EOS for the cam and lifter game. I was not aware of anyone recommending this stuff for breaking in a new cam. All I ever saw from the cam grinders was a moly paste that was used for initial break in while the surfaces mated. Most grinders recommended that the engine not run under 1500 rpm for the first fifteen minutes with the rpm varying during that critical break in period. It was important to vary the rpm as the cam was splash oiled, and different rpms put the oil in different places. Most well read oil fanatics will tell you not to use additives as you may upset the additive package. I tend to agree. The grinders also stated that if the cam survived the first fifteen minutes, it would probably live a very long life. I hope this helps.