[AT] Related Engine Oil Question

[Ken Knierim]

If you look around there are some oils with ZDDP in them but as Steve
points out, this "high mileage" moniker seems to be a marketing gimmick.

I found a version of Mobil 1 that has higher Zinc and is labeled for flat
tappet engines as I run some flat tappets and the new oils are credited
with eroding them quickly. I had slight wear on one lobe of a roller cam
(and fairly significant cylinder taper of about 0.004) on a recent small
block Chevy overhaul (1988 Camaro) so I did some checking. I found this:

https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-oil-product-specs-guide.pdf

I'm now running the 15W-50 as it has 1300 PPM zinc which is "around" the
level necessary to keep them alive from my limited internet reading found.
You can get more zinc but opinions vary on how effective it is... and I
know I can get this oil from Oreilly's about anywhere if I run out. It's a
little heavier than the required 5W-30 but I also run it in stop and go
Phoenix traffic and the oil pressure stays at the top end of the gage and I
worry about other things. You can find the ZDDP additive at parts stores
too... and end up paying more for the additive than the oil. Not sure why
or if I was looking at the wrong stuff but...

I wouldn't run this oil in my 1940 Case DH... it's a bit pricey for that
due to the tractor's leakage and low usage. However, the Camaro gets beat
on regularly and it's still pretty solid for 225K miles and 31 years old.
The teardown was because of bad exhaust valves due to a bad TBI fuel
pressure regulator leaning things out. Changed rings while I was in there.
Crosshatching was intact on the bottoms of the cylinders but the top had
wear. I equated this to higher friction at the high pressure end of the
power cycle (and my lead foot) and increased metal to metal wear due to
lower zinc. I don't have any solid data to prove this. It's been running
Mobil 1 for the last 15 years and 100K miles and it was clean inside the
engine. It works for me.

Ken in AZ

On Wed, May 29, 2019 at 2:06 PM Stephen Offiler <soffiler at gmail.com> wrote:

> Short answer is no.  These "high mileage" oils are still rated to the most
> modern API standard, which is SN.  The ZDDP disappeared after SF or SG or
> thereabouts.
>
> If you are looking for ZDDP, you will find that the oils marketed as
> "Motorcycle Oil" are rated SF/SG and will typically contain some ZDDP.
>
> SO
>
>
> On Wed, May 29, 2019 at 4:36 PM STEVE ALLEN <steveallen855 at centurytel.net>
> wrote:
>
>> The topic of Zinc in modern gasoline-rated engine oils has surfaced in
>> the recent discussion of tractor oil.
>>
>> Does anyone know if the "high mileage" formulations currently on the
>> shelves contain the Zinc additives desirable for non-roller cam engines?
>> Since these oils are sold for use in older engines, I wonder if they are
>> already fortified in that way.
>>
>> The "original" Steve Allen
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