| [GMCnet] Synthetic Oil [message #72786] |
Thu, 04 February 2010 10:36  |
fbhtxak
Messages: 191
Registered: April 2006
Karma:
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Senior Member |
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For N9KB:
Ken,
While I have had only a few courses in tribology (i.e., the
science of lubrication), I fully agree with your
observations (i.e., "Why Change", synthetics/old engine
technology and ZDDP/old engine technology, etc.).
I am amazed, however, that you have to add only one quart in
6000 miles at 90k miles on the clock. The "403" in my coach
has, since new, always required about one quart in 800
miles. 'Now has about 105k mi. I rent cars rather than tow
and set the cruise at 70 mph where speed limits permit. Not
surprisingly, less make-up is required at lower speeds
(about one qt. in 1000 mi. at 55 MPH). Maybe "455" Olds
engines were just made to tighter clearance standards than
the "403s"...
The old Airstream (w/Chev "454") in Alaska has about the
same make-up requirements as the "403" when driven
similarly. 'Not many roads, however, in Alaska where the
cruise control can be set - and maintained at 70 mph.
"454s", though, never did have a good reputation on oil
consumption.
Fred Hudspeth
'78 Royale - Tyler, TX
'82 Airstream Excella 28' Motorhome - Anchorage, Alaska
Date: Wed, 03 Feb 2010 21:04:37 -0600
From: Ken Burton <n9cv@comcast.net>
Subject: Re: [GMCnet] Synthetic Oil
To: gmclist@temp.gmcnet.org
Message-ID: <11c39.4b6a3944@gmc.mybirdfeeder.net>
Content-Type: text/plain; charset="ISO-8859-15"
My question to you is WHY change? Whatever the coach has
been using got it 100,000 miles in 30 years. If you are
not having oil consumption or other problems I would leave
it alone.
Synthetics run OK in a tight engine. If the engine is using
oil forget the synthetics. My engine has only seen Rotella
Dino oil since it was new. The coach had 2 POs and both
used Rotella. I use one quart in 6000 miles and the coach
has just under 90,000 miles on it.
Do not worry too much about the ZDDP as that primarily
affects new cams and lifters. After a few thousand miles
the modern (since 2008) lower ZDDP oils do not seem to be a
problem. I stocked up on Rotella before the government
formulation change. Newer Rotella still has 2/3 of the ZDDP
as compared to prior to 2008.
JMHO.
Ken B.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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