Peter Arakelian wrote:
>> Mobil now claims their 15w-50 is now engineered for older vehicles...
>> It has a lot of ash (1.2%) to prevent
>>
> ring
> sticking and oil analysis is showing it be well over 1,200 PPM zinc
>
>
>
> The problem isn't only zinc, the phosphorus is just as important. that is why
> the ZDDP additive or oils that have high zinc AND phosphorus.
>
> Peter Arakelian - '71 TR6, Daily Driver
>
>
I was wondering with all this discussion on proper oils - that maybe
someone explained previously - exactly what are the differences in our
older engines composition - ring to cylinder wall, valve stem to guide,
valve to seat, bearing journal to bearing, cam shaft to follower that
makes new oils - apparently completely unsuitable for older engines?
So I suppose the question is, what are the changes in metals and changes
in the oil composition lubricating those metals that makes the oils
destructive to older engines? It seems a logical question that motor
oils are developed to lubricate metal to metal contact, reduce friction,
and carry away impurities.
Anyone have any definitive facts with actual testing, or are we dealing
with the usual "someone put it up on their web site so it must be fact" ?
I think this is something that needs to be pursued by the automotive
engineers on these lists and given a complete report. This information,
substantiated or debunked, can make a real difference in the longevity
of our old LBC's, and once properly investigated should be made
available and properly footnoted with reliable references.
--
Glenn A. Merrell
Chairman, Triumph Stag Club USA (2007-2009)
The best trophies are miles on the odometer, stone chips in the paint, dead
bugs on the windshield!
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