> << In all oppsed engines, exceeding 4000 rpm for any lenghth of time will
>heat up the oil and
>>>pound out the main bearings.  This pounding even happens to Waterboxers.
>>>
>>>Dennis H.
>
>Why then do so many aircraft engines have horizontaly opposed engines? They
>run at that rpm for long periods.  Also why has porsche used horizontaly
>opposed engines for so long if there was an rpm limit so low?

Also why does it say in my owner's manual that the top speed of my 76 westy
is also the cruising speed of 72 mph (don't kow what rpm that is...)?

Eric
Maggie