Re: [Amc-list] Fwd: Oil requirements/filter by pass valve

[adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)]

" From: ksiroonian@xxxxxxx
" 
" 
" Also , on the oils and the zinc- I went to wall mart- saw the pre 1988 10w 40 oil for 1.39 a quart, and also the chevron, shell and mobil 10w 40 diesel oils, about 9.19 a gallon, all very reasonably priced. I have been using the valvoline high mileage stuff in my cars, none are for racing or other than light driving, going to a car show, under 500 miles a year.
" ?so for the reader's digest condensed version... is it still better to use these above oils with the extra zinc in them, or is it not needed, and are you guys recommending that stuff only for engine rebuilds and racing and such? Or is the GM EOS ok or even needed? I know in the AMC repair manual it does say to coat new engine parts in a rebuild with the AMC EOS, and I know for years dealers would add it to each oil change, though I always thought it was just a profit builder, like the 3 most profitable words in America.... lather. rinse.. repeat. I know many of you are into the racing and the performance and things so just wanted to get the readers digest condensed version. 
" Regards, Ken.

i agree with the experts; your engine was designed to use high-zinc
oil.  btw the sae set a spec on it [the first?  anyone know?] in the
late '70s by testing production engines with various zinc levels and
measuring wear.  mega-zinc oils like the joe gibbs break-in stuff,
well that's self explanatory - you don't and shouldn't run them all
the time.  adding eos on top of high zinc oil would accomplish much
the same thing, not routinely necessary.  adding it to today's low
zinc oil isn't the same.

i'd use the walmart stuff.  i'm tempted to run it in my '94 4.0.

do the diesel oils have an 's' rating at all, or just 'c'?  and btw be
aware not all diesel oils have high zinc any more either.  api 'ci'
and 'si' were the last high-zinc specs, but some diesel oils are now
rated 'cj'.  iirc still more zinc than 'sm' car oils though.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh@xxxxxxxxxxxxxxxxx                       and think what none thought
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