What about zinc?
You'll have to forgive me for asking, but what does "flat tappet cam" mean? I know I have solid ( non hydraulic) valve lifters that need periodic adjustment, but I really don't understand what a flat tappet cam is. Can you help? Thanks.
Flat tappet=non roller lifters. In other words, what you have.
I like to run higher zinc content than what's "off the shelf" in anything flat tappet anymore. Just my personal preference. I can link to thousands of sites and tech articles that support my opinion, but you can also find information that says it's not needed.
My opinion is, the zinc content in oils when these cars were new(er) was much higher. The engineers didn't put it there on a whim.
I personally use Lucas 10w30 Hot Rod and Classic oil with 2400 PPM of zinc. I've broken in and run several flat tappet cams with it and not had a failure yet. The "ZDDP" compound is a combination of zinc and phosphorus and provides both additional anti scuff wear protection as well as extra cooling. There's real science and history behind it, it's not an opinion. It's scientific fact.
Flat tappet camshafts scrub the bottom of the lifters and the lobes making contact and need that extra protection. Some say once the camshaft is broken in with ZDDP oil or additive, after that, it's safe to run modern oils with much lower content. My personal opinion is to continue running ZDDP oil for the life of the flat tappet engine.
ZDDP was in the original oils for flat tappet engines and I believe that's what's best. That's my opinion and I stand by it.
