Re: Oil changes alfa-digest V7 #696

[C M Smith <cmsmith@domain.elided>]

The mystique of oil... marvellous ain't it?

Black oil means nothing other than the oil is doing it's job. Most of the
mystique of oils dates back to the days of non detergent single weight
oils, including things like Castor Oil (Castrol derives its brand name from
these WWI aero engine lubricants). Modern lubricants are light years ahead
of the old single weights, and synthetics are substantially superior even
to modern conventional multi-grades.

Black means the oil is picking up dirt from the engine and holding it in
suspension between (among actually) the lubricating molecules where it is
harmless. The filter is removing anything large enough to cause any
problems (unless you make your own filters or buy substandard cheapies, or
forget to change the filter!). The old non detergent oils just left the
crud stuck to the innards of the engine where we all hoped it would stay.
Occasionally a bit of crud would break off and stick in an oil gallery
somewhere on its way back to the sump and filter, before it could settle or
get filtered out. ( Older humans suffer from similar problems, we call them
heart attacks, red wine apparently helps flush our lubricating system like
a good modern detergent oil cleans oil galleries, price of Agip is close to
French burgundy come to think of it).

One thing that could be useful when you make a major change in brand of oil
to a superior oil is to shorten the interval to the next oil change. Better
oil may have stronger detergent or flow faster or further into the nooks
and crannies of your engine, cleaning up some sludge not carried by the old
oil. Clearly shortening the interval would be beneficial as if you were
encountering more severe service conditions such as stop and go driving.
Also, different brands have different formulations e g Castrol tends to
leave a greyish sludge in the upper engine supposedly part of it's
"superior" formulation.

I have to disagree about the J D Power argument. It is clear that Alfa
couldn't care less about such things, the cars don't even have cupholders!
The reason manufacturers are recommending extended service intervals is
because their extensive real life testing shows it to be cost effective for
their customers. Newer oils are much better than older oils, the SAE
standards just keep getting higher. Also, good old Uncle Sam has done some
things right when it comes to cars. The emission standards once thought to
be impossible to comply with have accelerated engine development to the
point where new cars deliver higher specific output, using less fuel, and
requiring almost no regular maintenance,....except for changing the oil!

Don't get me wrong, I love older cars. Alfa's exemplify how little the
basic engineering has changed. Alfa has been overdesigning engines for
street use since, well forever, but particularly beginning with the
incredibly advanced wet linered four cylinder dating back to the early 50's
that every Alfisti is familiar with. The beauty of these engines is they
are so advanced they benefit from all the advances in engine technology
made since their original concept was laid down. The newer oils, better
spark plugs, unleaded fuel etc. as well as factory improvements in computer
engine management, variable cam timing etc. have all been adopted by Alfa,
pushing streetable outputs ever higher.

BTW, we switched to unleaded fuel in Canada a number of years ago. I concur
with other writers and confirm Alfa's are fine with unleaded of correct
octane rating. Unleaded is superior to Tetra Ethyl fuel for street use. The
change in tailpipe colour is an indication of how clean the new fuels burn.
Your plugs will also be clean and should display a light reddish tan colour
on the electrodes. If everything is firing properly, unleaded makes the
plugs look a little "hot" compared to plugs run on leaded, but if the
insulator is not glazed or blistered and the engine doesn't ping under load
the plugs should be fine. 

We get almost no deposits on the plugs, in the combustion chambers, or on
the exhaust valves, and the exhaust system should last a little longer.
Catalyst equipped cars tend to have even less "black" tinge to the tailpipe
reflecting the squeaky clean exhaust, but the brownish tan colour of the
tailpipe of a perfectly tuned engine run hard is pretty well a thing of the
past, the best you get now is no deposits at all, kind of a dull light
almost rusty pipe look, unless you're using stainless! 

Paradoxically, the new cleaner fuels do tend to leave deposits on injectors
and intake valves over time. Fuel system cleaners are highly recommended as
a routine maintenance for intake systems, the ones the professional shops
use are much better than the moose juice in a can, but anything is better
than nothing.
Michael Smith
Calgary, Alberta
Canada
91 Alfa 164L, White, original owner 

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