RB wrote:
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...
"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.
Air-cooled engines always have hotspots, no matter how well-designed.
That's why even Porsche and VW eventually gave up on air-cooled engines.
Briggs is not going to spec anything other than regular oil.
It would be a marketing nightmare for them, and a warranty issue.
"Don't buy a mower with a B&S engine. You have to use B&S oil, and that
stuff is expensive." They know that the original owner is rarely going
to put enough hours on the engine to wear it out, and even then it won't
be blamed on anything in particular. How many people are going to run a
mower 10 years until it just won't run anymore, then realize "If only I
had used motorcyle oil I'd get another 5 years out of it." ?
As to wear additives, it's true that the best of them has been
eliminated for the sake of emissions, specifically catalytic convertors.
That's a great tip on using bike oils. I'm going to check with my Lucas
rep and see if their Motorcycle Synthetics will work in my non-catalyst
cars. I think racing oils should also still have the anti-wear zinc and
other additives.
Yabbut the thread was for small lawnmower engines, not racing or other
extreme duty applications. There's little need nor anything to be
gained from using anything greatly exceeding the OEM's API
recommendations in normal use.
Virtually any quality automotive oil of proper viscosity rating of the
last 20-30 years will be more than adequate since the advent of the
higher-temperature running auto engines beginning in the 80s for the
emission controls. In the 50s thru say 70s the requirements were pretty
minimal and some might show some temperature breakdown in air-cooled
engines I'll agree but that's pretty much gone by the by...
Again, high performance bike engines, etc., etc., aren't/weren't the
subject. Using such won't hurt anything and the small quantities
required means it won't really cost a whole lot extra but it generally
isn't really going to make any difference ever be able to tell.
As noted upthread, we're running some 30-40 yr-old small engine
equipment regularly. For most of their lifetimes (until Farmland Co-op
closed their refinery and quit manufacturing it) they ran on an
all-purpose API SE/SF/SD multi-grade that included full engine warranty
(including the turbochargers) service and a drained oil sample test kit
returned at every change for all of the trucks and tractors. After that
went away and w/ the arrival of the larger crankcase capacity tractors
went to bulk JD multi-grade but not synthetic -- JD did not recommend
switching to synthetics on engines formerly not on them. Use it in
everything...
--