Re: oil consumption

["Barton P. Chambers" <bchambers@atlantic.nos.noaa.gov>]

> >   Carl DeSousa sagely replies:
> > 
> > > You can start by switching back to regular dinasour oil.  
> > > Synthetic oils burn faster because more of it gets by the rings
> > > especially during the first cold start.  
> > > The benefit of synthetic oils are better realized in turbo motors anyway.
> > 
> >   Bart Chambers chimes in with his "me too":
> > 
> > Most knowledgable folks I know agree that clean fresh oil is the most 
> > important thing for keeping your engine happy and healthy for a long time.  
> > 
> > changing oil frequently (say 3000 miiles) is far more important than 
> > (arguable) 
> > gains obtainable from using *any* synthetic. 
> 
> Bob Kunz in *HIS* infinite wisdom replies:  :-)
> 
> It and the filter are changed at 5K intervals.

> In any event, sythetic oil has a higher breakdown temperature and more
> consistant viscosity over temperature range. This means that cold starts
> are easier and that heat drench after shut down will not oxidize as much
> oil if it's synthetic. Take a look at your camshaft lobes through the oil
> filler port and if you have been using mineral oil you'll most likely see
> coke buildup there. The smaller oil passages will coke up fast in this
> way.
> 
> Regardless of what engine manufacturers would have you believe there is
> a break-in period to get all the metal surfaces "used to" each other. This
> is the time to switch to a sythetic oil. If you wait until the engine is
> nicely worn expect oil loss when switching since you are effectively
> putting in a thinner oil. Perhaps this is what's causing Graham's oil
> consumption. I agree that using a mineral oil may be best in this case.
 
While Bart (never one to keep his yap shut and be thought a fool when the
opportunity to remove forever all doubt presents itself) further adds 
(probably unnessecarily, at that):  :)

The things you say about synthetics are true, and we agree that Graham
would be best served by switching.  In *extreme* conditions (very-high 
output engines involved in endurance racing, etc.) synthetics might well 
be the appropriate choice.  Otherwise, however, we diverge on the implied
superiority of synthetics for a street engine, properly broken-in, kept in 
that blissful state of fresh, clean oil (changed every 3000 miles (I admit, 
I failed to mention that the filter should be changed with the oil)).  If 
you keep your oil clean, you are *un*likely to see any coke build-up, etc. :)

Cheers,

Bart Chambers
'77 Feline Varmint Felix, Gray Tabby
'86 Carrera Cabriolet, Guards Red
'87 Syncro (Stealth Quattro