Re: oil consumption

[Bob Kunz <bkunz@hpbs114.boi.hp.com>]

>   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:  :-)

I've used Mobil 1 15W-50 in my '86 5000s wagon since the 10,000 mile mark.
It and the filter are changed at 5K intervals. For me this translates to
once every 9 months or so since I ride my bicycle to work. It used to
help that my dad worked for Mobil in the Princeton labs (used to get the
stuff for free) but he's now retired.

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.

--bob