RE:Synthetic Oil & Flat Cams

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

From: "Joe Cabibbo" <joe_cabibbo@domain.elided>
> Subject: RE:Synthetic Oil & Flat Cams

> >>I have heard of more than one case of rapid cam lobe
> deterioration (in under, say, 10K miles) after switching
> to synthetic oil from conventional oil on Alfa V-6es 
> with around 60K - 80K miles.
> 
> My experience seems to support this. I switched to synthetic when I 
> bought my Milano 2.5 at ~60K miles, and had significant wear on my stock 
> cams when I changed to 164S cams at 86K miles. The wear was especially 
> bad on the #5. 

My experience, and the owner's manual, don't support this conclusion. The
owner's manual specifies synthetic oil.  The V6s come from the factory with
synthetic in them.  The oil change intervals specified by the factory require
synthetic oil (and would be catastrophic with conventional multi-grade oil).

If your cams showed significant wear after 80k miles with synthetic, they
would have shown the same amount of wear after 30k to 40k miles with multi-
grade.  Likewise, if non-synthetic oil was used for a significant portion of
an engines life, the wear on all parts would be increased (not just cam wear).
> 
> Even though I used synthetic I do not allow long change intervals, and 
> also never rev when cold. However, the miles after switching to synthetic 
> were definitely hard and fun, for the car and me, respectively.

When multi-grade oils came out and the manufacturers moved the oil change
intervals from 1k miles to 2.5k or 3k miles, there were lots of guys who
mistakenly believed that extended change intervals could not work.  This is
just more of the same.  If you are changing synthetic oil more frequently than
the 7500 miles specified by Alfa Romeo, you are throwing away you money just
like those guys were.  

And if you switch from synthetic to multi-grade oil, you are accellerating the
wear rate of your engine.

Chris Prael

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