Re: [AMC-list] High Zinc Oil

[Frank Swygert <farna@xxxxxxxxxxx>]

Date: Thu, 14 Mar 2013 19:09:47 +0000
From:amcngmc@xxxxxxxxx

Really now ? ! Most oils today have 25% less then the ones I found at AMSOIL. I been hearing that diesel oil isn't even a good go to oil any more.

Since 2009 I had been reading that diesel oil has drastically dropped the Zinc/Phosphorus levels.
============================

Yes, zinc and phosphorous has been cut even from diesel oil, though diesel oil still has more than regular automotive oil. There are some high pressure wear replacements in diesel oil too -- it should still be better in that respect than regular oil.

I had a discussion with an oil engineer from Warren Oil. He stated that stock engines should have no problems with regular oil even with the lower ZDDP content AFTER BREAK-IN. He did state that a break-in oil or additive was needed, but after that there should be no appreciable increase in wear. If you're running much stiffer than stock valve springs a racing or off-road oil, or a ZDDP additive is necessary. The key is valve spring pressure. He stated that regular oil will be fine for any stock valve spring pressure in a normal engine. Some of the early 60s hi-po engines might have springs that are a bit stiff, but no factory AMC engine came with stiff springs and should be fine. I had asked specifically about a Warren blended oil that stated it was for pre 88 vehicles (indicating a higher ZDDP content). I think it was an SF rating. He confirmed that it had higher ZDDP and met the older SF rating, and was intended for pre catalytic converter vehicles. He also stated that he w
ouldn't personally run it, as the newer SM rated oils are a much better formulation. He has a couple old cars himself, late 50s/early 60s IIRC, and runs regular oil in them since they are basically stock. One was a mid 60s muscle car, don't even recall if he stated what make/model it was.

--
Frank Swygert
Editor - American Motors Cars Magazine
www.amc-mag.com


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