Thread: Break in oil

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Originally Posted by Bob Parmenter

Jay, as usual, you are at the front of the knowledge curve. Ironically I was commenting on the 302 pressure thread about the same thing at apparently the same time. Just a couple of "clarifications" if I may.

In your pp4 I don't think you meant to say what it looks like it says about zinc "ruining" flat tappets. As is apparent in the previous statement, it protects flat tappets. Just didn't want confusion.

To expand on the emissions comments, it's the phosphorous component of the zinc primary additive that "contaminates" cat converters. It's not necessarily an initial polution measure problem, but rather long term degredation of the cat converter............manufacturers are on the hook for emissions performance for longer time/mileage accumulation than before.

As for using Mobil 1 for older, flat tappet engines, as long as they have a current C class API rating that may work, but if they are also SL rated they may at best be border line for sufficient zinc level. See comments in the other thread to save me some typing. Diesels are highly likely to employ cat converters down stream and when they do, qualifying diesel engine oils too won't help. Sadly we in the "old car" world will have to move to "specialty" oils........................I hate that because it will foster an environment for exploiting the uninformed.

Bob,I made a post a couple of weeks ago about the zinc additive.
Check -out www.joegibbsracingoil.com this should clear up anything and everything about zinc.
Click under oil bulletin's.
I see you have already found the site.