Robert et al: What I think I was trying to convey was my simple approach to
this confusing issue. While some folks do take enjoyment from digging
through the data for a thorough understanding, I prefer finding a simple
solution that will keep me out of trouble. While just about every facet of
this has exceptions, there are some simple rules that will help avoid
problems. For instance, I will avoid any oil rated "M" or later. Knowing
nothing more, "L" or earlier is safer if you're in a spot and need to select
something. When in doubt, add an appropriate amount of EOS or STP (red or
blue - I don't remember, but it is important to choose the right one). I
have taken from the LN Engineering site a ratio as follows: "By our
calculations, between .5 and .66 oz of GM EOS has to be added to each quart
of oil to raise the Zn and P by 100 ppm each." . I don't know if STP is the
same or not.
As a regular oil choice for your shelf, oil changes, on-board supply, choose
one that you're comfortable with and trust and stay with it - but keep your
eye on the API rating should it ever change.
I had been okay with Valvoline VR1 Racing oil until I saw that it had the
double SL/SM rating. The fact that SM showed up on the label to me implies
something must have changed. I did see that the spec sheet says "ashless".
Well, I don't want to find out someday that we need ash. I'm going with
Brad Penn. In a pinch I'll add some ZDDT to something else. There are other
good choices, I'm sure.
Regards,
Mike Lempert
From: "Robert Blair" <rnbmail@yahoo.com>
Sent: Tuesday, February 05, 2008 8:27 PM
Subject: Re: [Healeys] Oil article abour ZDDP
> Hi listers, The beat goes on on the oils discussion - interesting
>
> [First appologies - VR1 is of course Valvoline - not Chevron]
>
> Second, oil is a competitive market, and is just another target for
> confusing and in many cases false advertising. Most consumers are not
> chemists or metalurgists and so the marketing message has to be reduced
> to a very few simple codes.
>
> The catalytic degredation by Phosphorous is real, and so the downward
> trends of ZDDP levels is justified for newer engines with newer design
> tolerances and metalurgy, plus huge cats.
>
> So for us older folks with older engines we must maintain 'adequate'
> levels of zinc - metal surfaces are not as tolerant/smooth and the
> tolerances/gaps are designed to be larger. Adding to the problem is
> that weighs have dropped to match the smaller tolerances - typically
> 5W30 for a modern engine - adding to the tolerance/gap problem of older
> engines.
>
> My take - keep the weight up, make sure there is 'enough' on board
> ZDDP, or add 'enough' ZDDP to a modern cat saving oil, change often.
>
> Robert.
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