Oil life - Semi synthetic, etc.

["Daegrigg (Don)" <daegrigg@domain.elided>]

The data Tom sites re. low contamination rates for synthetic oil is
impressive.

I would like to see a discussion/experience of SEMI synthetic oils which is
what Alfa specifies for the 91-93 V6s.  I started using semi synthetic about
two years ago in a effort to improve oil consumption on my 91 S.  The
consumption improved perhaps 15-20 percent to about 700 mi/U.S. qt.

If I use Alfa's 10K change interval, I more than "change the oil" in that
distance.

Would this periodic replenishment of the chemicals in the oil keep the
contamination down to an acceptable level -what ever that is.

How would my 10,000 mi oil replace by 120 percent compare to a brand new
sump full of semi synthetic oil?

 Assuming filter changed at the correct interval. Interested.

Thanks,

Don
---- Original Message -----
From: <Iopsycheng@domain.elided>
To: <alfa@domain.elided>
Sent: Sunday, March 02, 2003 9:38 AM
Subject: Re: alfa-digest V9 #304


> Karl,
> The biggest part of your problem is not being aware of the product you are
> using. Synthetic oil does not have to be changed every 3000 miles. I am a
> defense contractor and during a diesel engine maintenance contract for the
US
> Coast Guard I had the opportunity to work very closely with several
petroleum
> engineers. Because of the large amounts and multiple duties it must
perform
> lubricating oils on shipboard diesels are not changed frequently. What is
> done is the oil is analyzed for contamination. Without getting into great
> detail the condition of the oil is inspected chemically and then any
> decencies are corrected either by chemical addition, replacement of the
oil
> or physical repairs to the engine. Not being any happier with the cost of
> synthetic oil than you are I asked about the claims of 25,000 mile
> protection, cold/hot weather stability etc. What I learned would fill
volumes
> but in a nutshell synthetic oil is many times more stable chemically than
> parrafin/asphaltic based petroleum oils. The contaminates which normally
> affect these oils have minimal affect on the chemical bonds in synthetics.
> To test what I had learned I decided to risk an Alfa V-6 engine. At the
time
> my GTV-6 had about 7,000 on a rebuilt engine. I had lost a timing belt at
> 53,000 miles and had just completed the first year back on the road. (I am
a
> machinist by trade and the GTV-6 has had Mobil 1 15W-50 in it since it had
> 16,000 miles. During the rebuild I measured ALL moving pieces for wear...
> Nothing was out of factory specs...) I changed the oil and drove the car
as
> my daily driver for the next 11 months. I drove through 100 degree stop
and
> go June traffic in Virginia and I slogged through 19 degree winter and
> everything in between. After 7500 miles we took an oil sample and compared
it
> chemically to a sample taken from a new bottle of oil. There was less than
5%
> degradation of the used oil, well within safe operating parameters. I ran
the
> oil another 6300 miles before the next test. It had still only dropped 8%
> total. According to the petroleum engineer the oil in my car at 13,800
miles
> was still a better lubricant than most of the other oils available. I
asked
> about filtration and was told that using the largest, best quality filter
is
> a must as the filter helps trap not just solid contaminants but some
chemical
> ones as well. I was also told that the filter could be changed and the oil
> level simply topped back up. Jacking the car up on the filter side and
> letting it sit overnight will drain the filter and reduce the mess
factor...
> Anyway, I run all of the Mobil 1 products in all of my Alfas, there are
> eleven, and in my Toyota and in everything else, mom's Dodge, the outboard
on
> the sailboat, etc. Currently my 164L has Mobil 1 15W-50 in the engine and
> Mobil 1 ATF in the transaxle and the power steering system. I use the same
> oil year round in all cars and I use the various ATFs or gear lubes as
> applicable. I have never had any lubrication related problems. None of my
> four V-6s have the oiling mod to the head and all have 55psi or better at
> 3,000rpm and all are over 100,000 miles. Removing the valve covers reveals
> honey colored aluminum and absolutely no sludge anywhere. Oh, the Toyota
has
> over 300,000 miles!
> If you change the oil every 7,500 your cost will be about the same as
normal
> oil changes every 3,000 miles. One other thing I learned. Because of the
> synthetics unique properties, solid contamination is significantly reduced
> and chemical contamination is more easily burned off during long runs,
> therefore filter life is also extended. I cut open one of my oil filters
> after 7,500 miles and it looked better than one I took off of my in-laws
year
> old Chrysler. I would suggest going to 7,500 mile oil and filter changes.
Of
> course all of this assumes an engine in good operating condition. No
> lubricant is going to repair a damaged engine and abusing a cold engine
still
> isn't a good idea but today's synthetic lubricants are light years ahead
of
> regular oils.
> Thomas A. Gonnella
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