On Thu, 18 Jun 2009 21:25:18 -0500, dpb wrote:

wrote:
...
For 4 stroke engines do NOT use standard automotive engine oil as it
has no zinc compounds in it any more for extreme
pressure/anti-friction. It has been taken out for emission control
reasons - if the engine burns any oil with the zinc compounds in it,
the catalist is compromized. Apparently it is still allowed in the
heavier oils like 20W50, but that doesnt mean the brand you use will
have it.
The special 4 stroke equipment and bike oils still have it. Use them
for best engine life.

BS...a small 4-cycle engine has higher lubrication demands than an
automotive engine? I don't think so and B&S doesn't either...

Air cooled engines DO have higher lubrication requirements - and the
low TBO or lifespan of most small engines definitely affirms that.

"Briggs & Stratton lawnmower oil is formulated...and approved by Briggs
& Stratton engineers-Warranty certified and recommended in all Briggs &
Stratton manuals-A high quality detergent oil classified SJ/CD by the API"

The API classification is nothing different than that for most modern
automotive applications.

I seriously doubt you'll find any ordinary small 4-cycle engine have any
special requirements more stringent than the above.

About 98% of the older small engines will last a WHOLE LOT longer with
oils containing ZDDP. Any engine with flat tappets will have
significantly less cam wear with ZDDP. The only reason current auto
oil does not have it is because it can affect catalytic converter
life. Any SL or previous engine oil is acceptable for small engine
use.. Racing oil and Deisel or Multi-Fleet oil is also acceptable.They
all have about 12ppm ZDDP, compared to a maximum of 0.08%

Today's roller tapet engines are much less demanding lubrication-wise
than flat-tappet engines.