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I certainly agree, Bill, and have said so many times -
even a small change can spell problems or if you don't really understand
what a particular subsystem is doing or how it functions, what problems it may
be susceptible to. Any leak in the suction side (for what ever reason) and
you are going to problems getting oil pressure up quickly. The
rotary can fly at least for a while with a cooked engine (coolant /pump
loss), but lost of lubrication will cause it to seize quickly like any
other mechanical device not properly lubricated. One small crack or pin
hole in the welding of an oil pickup tube is all it takes to cause a
problem.
The bottom line is if your system does not show oil pressure
within 1-2 seconds (or less) after firing the engine, then I for one would
immediately find out why and fix the problem. While the rotary bearings
can apparently take quite a bit of abuse based on Lynn's experience - every
start with inadequate oil pressure is (in my opinion) one start closer to a
possible bearing failure.
Additionally, there is some indication that the combination of
the positive pump pressure pulses and the high oil pressure of the pump (which
apparently can approach peaks of 156 psi- based the rating of oil
controller (not regulator) trip point) can cause oil coolers of less than a
robust design to fatigue and spring leaks. If you look at the stock RX-7
cooler and compare it to a number of automotive oil cooler you can immediately
see that the stock cooler is heavy and robustly built - one would
presume for a good reason. There are non-rotary oil coolers that would
appear to be constructed to the same standard - mostly build for the racers -
which would probably work just fine. However, many of the less expensive
oil coolers are of a less robust construction. I initially used one
of EARLS oil coolers of considerably less robust construction and while I
flew almost 60 hours with it - I am very glad (knowing what I now know) to
have switched to the stock oil cooler.
Ed A
----- Original Message -----
Sent: Sunday, May 22, 2005 1:40 AM
Subject: [FlyRotary] Re: Seized 13b
Wait Bill, I am not certain if you are referring
to MY oil system or what I reported on from Andy on
HIS oil system{:>).
Ed please rest assured I didn't mean YOUR system. Rather that of
the engine that seized!
Please know also that I don't mean to infer that plugs up can't be done
well. I do believe that many people don't understand the extent of what they
are taking on and when making the changeover.
Bill Jepson
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