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I have finished my restoration    ---I HOPE---of my 31 Plymouth motor that has been rebuilt   I am running 10w30 Pennsoil---I find it holds an more even oil pressure at the gauge that straight 30     ---I have read the posts about adding zink to motor oil and understand the reasons --------- the opinions are all over the place---- so  I guess I just would like an update from every one ,   could I add to much zink !!!!--I have used  ZDDP in the little bottles, should I go with an oil that already has it  ,,,,,I  do not drive my car hard --------Please let me know what your think----thanks


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From admiring this picture, and the two in your profile, that is one fine looking, beautifully proportioned car ! Sure, you don’t need to second guess the lubricant companies and brew up your own additive package. If having a little dab of ZDDP to do the peace of mind thing, why not use an oil which has it ? I do not know what the current state-of-the-art in motor oils is. Just a few years ago, it would have been Amsoil’s Z-rod. It has way more ZDDP than you need, or might think you need. Way under the overload threshold of O.D. ing on the stuff. But it is a very fine full synthetic with what at the time was the best lay up properties. Formulated for older cars which are not daily drivers. Please check it out, and if any better motor oil for our oldies has eclipsed this stuff, I would like to know. I am also over obsessed with lubrication minutiae. Make sure to use synthetic grease in all appropriate locations. Lots of opinions regarding motor oils, but no worthwhile dissenting opinions against synthetic grease.    -   Carl 

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I agree with Oldtech, an early car doesn't need it. The zinc is ostensibly for high spring rates that put extreme pressure on the flat-tappet lifters on a cam, and even then I'm kind of dubious about the need for as much as people claim. Your car will be just fine with just about any oil you prefer, no additives required. If, however, you do want the peace of mind, there are indeed oils with extra zinc already added. I like PennGrade1 oils (formerly Brad Penn, formerly Kendall) which have more zinc than the oils off the shelf at AutoZone. There are certainly others so you should be able to find something that suits you. Don't over-think it or worry too much about it, it's really a non-issue for a car of this vintage.


Hope this helps!

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