|
Well, George, appreciate all the engineering accolades you are
laying on me. However considering there have been a number of "Plugs UP"
installations in addition to mine that have never had any problem with
lubrication, I think your caution somewhat exaggerated.
The "bad" sump was (in my opinion) using a rubber hose
on the suction end rather than a metal tube. Any air leak at all and you
lose your ability to pull the oil up. If the hose lost stiffness due
to heat, it could partially collapse also restricting oil flow.
But that apply to the pickups in the auto orientation as well. If
you have a leak (didn't use a gasket, sealant, hole in the pickup tube,
stuff stuck on your screen, etc) on the suction side, you are going to have
trouble getting oil pressure quickly.
Now, I for one would consider it a problem if I couldn't
get oil pressure within 1-2 seconds of firing up the engine
(regardless of orientation) , I would cringe thinking of metal on metal rubbing,
heating, eroding, etc. I couldn't stand it and would have to fix it.
But, I try to avoid over generalization based on a case of one
instance. It would be like me saying that because I had apex seal
failure and was using a "Used" rotor that everyone should refrain from using
"pre-owned" rotors. Its like most other things in his "hobby", if you
don't pay attention to the details and look at the possible failure modes,
it may bite you. We now know to pay more attention to
the condition of the apex seal slot than we perhaps did before. Fuel,
cooling, ignition, etc are all equally critical (and some would say more
complex than lubrication - equally critical). So thinking about and
understanding your installation is the most time productive thing you can
probably do.
However, George, There is a very valid reason I can
think of not to go "Plugs Up"
All the vendors (motor mounts, PSRUs, exhausts, intakes,
etc) are building their products for the Automobile orientation (which is the
most common orientation). So if you want a compatibility with their
products, then clearly "Plugs Up" is a drawback. I had to adapt Tracy's
PSRU mount to my particular installation - not a big problem, but clearly one
due to my "Plugs Up" orientation. There are a number of advantages in my
opinion, but not trying to sell "Plugs Up", so will refrain from enumerating
them.
FWIW
Ed A
.
----- Original Message -----
Sent: Friday, May 20, 2005 1:08 PM
Subject: [FlyRotary] Re: Sized 13b
He
said that the engine was mounted "plugs up" with a home made dry sump system
that allowed the engine to run without oil pressure on start up until the
system primed itself. The results was that all the bearings in the engine
were "wiped out" completely (didn't size up really just stopped).
Geeorges,
It must have been a really bad "dry sump." Since the engine seized
there as a bad problem. This is a very unusual failure mode for a rotary, that
has actually started. A typical dry sump system uses a tank remote from the
engine that would always have oil above the pressure pump. I would also
suggest that unless you are real familiar with the engine to avoid plugs up
installation. With all deference to Ed A, most of us aren't ready to set up
that plumbing. I am not claiming that it won't work, Ed's obviously does, but
you are responsible for the configuration, rather than the original engines
engineers. Some people aren't that mechanically capable.
Bill Jepson
|