Dave, et al;

The Internet consensus seems to be that the bobistheoilguy website is
the 'resident expert' on automobile lubrication. I do not wish to get
into a long drawn out discussion rehashing information that is freely
available.  I have read the comments regarding ZDDP and modern motor
oils on the aforementioned website as well as various other sites
(including camshaft grinders such as Bruce Crower  and Dave
Schneider.) I have made, what is to me, an educated decision to use a
motor oil with the highest concentration of ZDDP in MY vehicles. You
are more than welcome to research the subject as fully as you desire
and draw your own conclusions.

< http://www.bobistheoilguy.com/motor-oil-101/> is a great place to
start then Google, "When Good Cams Go Bad" for contradicting
information.

Spend an evening doing the research and as I said, draw your own
conclusions. (BTW & IIRC, Bob is the Oil Guy recommends SAE 0W30 oil
as it flows well cold. Not in any vehicle I own, thank you.)

Ya pays yer money and ya takes yer choice.

Regards,

Jim

Right knows no boundaries and justice no frontiers.
--Learned Hand

On Nov 3, 2012, at 4:48 PM, Dave Mcneely wrote:

> Jim and others, my understanding is that the ZDDP concentration in
> modern oils is the same as it was in the 1950s (about 600 ppm), when
> it was introduced to protect the valve and tappet design then
> current.  The concentration was increased later for a different
> reason, having to do with detergent properties of oil.  Since
> catalytic converters have been required, the ZDDP concentration has
> been dropping to keep the converter functioning for 150k miles, but
> it is still adequate, with other changes in oil formulations, to
> protect the valves in older vehicles.  In fact, if I am not
> mistaken, I got that information from the same GM author that your
> citation references.
>
> I am stating this from memory, rather than from reviewing the
> original report I read right now, but I do think I am remembering
> correctly.  The particular link you provided only gives data on
> oils, but the report I read (same author)  discusses backwards
> compatibility of "star burst" oils (the modern service rated oils
> with the starburst symbol like), and the testing and results for oil
> service ratings
>
> Basically, the report referred to the "myth" that the ZDDP levels in
> modern oils are too low to protect older engines.
>
> Correct me if I am wrong.  If so, I hope you will explain more
> completely than I have.  mcneely
>
> ---- Jim Arnott <jrasite@EONI.COM> wrote:
>> Jack,
>>
>> 5W40 Rotella T6 synthetic. That big Arkansas box store. $20/gal. And
>> no.... the oil specified in the '84 owner's manual is no longer
>> manufactured. As engines have moved away from a flat tappet design,
>> manufacturers have changed the oil specifications. Typically removing
>> the zinc (ZDDP) necessary for reduced cam wear in our engines. Diesel
>> spec oils have the maximum in currently produced lubricating oil.
>> Rotella T6 synthetic has the highest concentration of all current
>> mass-
>> produced motor oils.
>>
>> < http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2330040#Post2330040
>>>
>>
>> Jim
>>
>>
>> Kindness in words creates confidence. Kindness in thinking creates
>> profoundness. Kindness in giving creates love.
>> --Lao Tzu
>>
>> On Nov 2, 2012, at 9:27 PM, Rocket J Squirrel wrote:
>>
>>> I'll need to bust out the owner's manual to see what they recommend
>>> for
>>> the Cold Season. Nights down to mid-teens (F), days up to 40s. Is
>>> this
>>> ca. 1984 manual still my guide to all things engine oil?
>>> --
>>> Jack "Rocket j Squirrel" Elliott
>>> 1984 Westfalia, auto trans,
>>> Bend, Ore.
>
> --
> David McNeely