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[GMCnet] Synthetic oil. Just some thoughts [message #282713] Tue, 21 July 2015 16:27 Go to previous message
fbhtxak is currently offline  fbhtxak   United States
Messages: 191
Registered: April 2006
Karma:
Senior Member
Kerry,

"At market" = the lowest price for oils bearing the same API "donut" as
nationally/internationally branded oils.

The difference in price is due mainly to the latter's cost of promoting and
distinguishing themselves from their competition and "what the market will
bear". Some sell the same product to large retailers but privately labeled.


Correct - the API spec is the most important factor in my selection process
- not brand.

The most recent (2010) API Service Classification is SN but SJ, SL and SM
are still in production. I prefer SN 10W40 for my "403"(GMCMh) and
"454"(Airstream) engines as it is the most technologically advanced (but I
do not pay a premium price for it relative to the others).

The SN spec was effective in 2010 and is backwards compatible for
"conventional" automotive engines (including "old technology/flat tappet"
engines). I should have emphasized "conventional" in my earlier comments on
this subject as my XOM engineering sources did so. John Lebetski's note
below properly clarifies that for unconventional high revving/high output
engines.

Acknowledging Rob Mueller's comment below: while there is no documented
evidence that spiking current API spec oils with moly and ZDDP increases
service life for "conventional" engines, there is no apparent downside to
doing that (except for the extremes on ZDDP that John noted).

A couple of informative links on engine oils:

. API Classification for Passenger Car Engine Oil:
http://www.pqiamerica.com/apiserviceclass.htm

Note that the API Service Classification was SE during the time GMCMHs were
produced - now long obsolete.

. Knowing what Oils Not to Use:
http://www.pqiamerica.com/devilsindisguise.htm

Fred


Fred B. Hudspeth
1978 Royale - Tyler, TX
1982 Airstream Excella 28' Mh - Cooper Landing, Alaska


Date: Tue, 21 Jul 2015 05:59:56 -0600
From: Kerry Pinkerton
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Synthetic oil. Just some thoughts
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Content-Type: text/plain; charset="utf-8"

fbhtxak wrote on Mon, 20 July 2015 13:45
> Like Bob de Kruyff, I am also a proponent of buying current API-spec
engine oils "at market"(including "house brands"),...


Fred, what does 'at market' mean. Are you saying that you worry about the
API spec and don't care about the brand as long as it meets the API-spec
you want. If so, what API spec do YOU prefer?
--
Kerry Pinkerton

North Alabama



Date: Mon, 20 Jul 2015 16:18:21 -0600
From: John R. Lebetski
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Synthetic oil. Just some thoughts
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Fred I agree. Paranoia sells product. At first any cam lobe failure was
blamed on low ZDDP when there could be a number of reasons contributing to
the
failure. It's mostly about lifter foot pressures. High RPM muscle car
engines benefit with ZDDP as they run steep cam ramps and strong springs to
stop
float. We do not (or should not) run those valve train styles. Worst you can
do is add too much ZDDP as the phoshoric acid attacks and causes spalling
at about 2000 PPM and above.
--
John Lebetski
Woodstock, IL
77 Eleganza II
Source America First


Date: Tue, 21 Jul 2015 12:17:18 +1000
From: "Robert Mueller"
To:
Subject: Re: [GMCnet] Synthetic oil. Just some thoughts
Message-ID:
Content-Type: text/plain; charset="us-ascii"

Fred & John,

Add me to the list.

YES I know I've stated that I add ZDDP and Liqui-Moly but I do that from the
standpoint of "it won't hurt."

Regards,
Rob M.
The Pedantic Mechanic




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