jon@dakota-truck.net wrote:
<snip>
> I'd be curious to hear what an authority such as Blackstone would
> have to say on the subject. Speaking of which, I suppose you could
> send a sample of the oil to them and they could tell you if there's
> been any degradation of the additive package and such, though that'd
> probably cost you almost as much as what your Dad originally paid for
> one of those cases of oil. :-)
>
Ask and ye shall receive:
They don't specifically address shelf life in this email, but I sent in
a sample of red-cap M1 15w50 that I know for a fact is 8 years old
[still had the receipt taped to top for a refund I never sent in for]
and it tested exactly the same as my original baseline test.
------ Original Message ------
Received: Wed, 16 Jul 2008 12:03:23 PM CDT
From: Jim Stark <jims@blackstone-labs.com>
To: "Barry Oliver" <barryoliver@usa.net> (by way of Blackstone
Laboratories <bstone@blackstone-labs.com>)
Subject: Re: Oil age question
> Barry,
>
> You can't wear an oil out. The reason they have to be changed is
> they get contaminated or in some cases, the active additives in the oil
> (active in the sense of their ability to neutralize acids) may get
> depleted. We have a TBN test that measures this ability of an oil to
> neutralize acids. But the oil soldiers own, regardless. If you can
keep
> the oil clean you can leave it in use for a long time. If the TBN gets
> down near zero you can spike the additive group, though make-up oil
usually
> takes care of this chore. If you use no make-up oil than you can but a
> cocktail additive group to replenish the active additive.
>
> One more thought. The oil itself takes care of about 98% of
the job
> of lubricating, cleaning and cooling. The additives don't accomplish
much
> more. Aircraft piston engine oils work in the toughest environment
of any
> engine oil and they are pretty much sans additives. No zinc, no
detergents
> and they work fine. An aircraft oil doesn't have a TBN. They do
have an
> ashless dispersent in them (all except those labeled mineral, which are
> used for break-in) to help keep parts clean.
>
>
> Jim Stark
>
>
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