Re: Synthetic oil for 60's/70's cars?

[Chris.Prael@domain.elided (Chris Prael)]

> Date: Tue, 30 Mar 1999 11:27:53 -0500 (EST)
> From: "C. Peter Audet" <paudet@domain.elided>
> Subject: Synthetic oil for 60's/70's cars?
> 
> With this oil thread dripping along: are synth oils ok for the 60/70's
> 1750/2000? seems to me the older P-cars don't like it unless a modern
> gasket set has been installed during a rebuild...orig. gasket material 
> prone to deteriorate with synth.?
> 
> Peter, not an authority on this subject...
> London, Canada

Actually, it is a little more interesting than that.  Any change of oil
brand or type tends to result in steadily increasing oil leakage.  

The reasons for this are that every oil refiner uses a different mix of
detergents in their lubricants.  As an engine ages, it tends to acquire
a fine layer of laquer-like deposit on all the inner surfaces, including 
all of the joins.  When you change the oil type or brand, the different
detergent mix disolves the deposits and the engine starts leaking oil
at every seam.

So, once you start using a particular oil, you want to stick with it!

Another thing to note is that synthetic oil is much more slippery than
single or multi-viscosity refined oil.  (On a race track refined
doesn't become a surface hazard until there is enough to be see from
the side of the track.  With synthetic, a deposit so finely misted that 
it was not visible right next to it has been slippery enough to put me
on my butt!)  

Auto manufacturers required that single viscosity oil be changed every
1000 miles.  The required that multi viscosity oil be changed every
2500 or 3000 miles.  With synthetic oil, Alfa recommends that the oil
be changed every 7500 miles!

So, when you rebuild the engine, use refined oil for the first 1000
miles to break in the engine.  Then switch to synthetic oil.  The
engine will last a lot longer.

chrisp

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End of alfa-digest V7 #602
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