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Message
Rusty,
Thanks for the info…..It is Wayne’s engine. I
would like to ask you a couple more questions about them. I could email you
privately if that OK? Also, I ran across the site in AU. They have some
interesting ceramic seals. http://www.selectmaz.com.au/apex_seals.htm.
Thanks
Dean
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Russell Duffy
Sent: Sunday, April 04, 2004 6:26
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Apex
seals
I’m trying to back track and gather some info on the
engine that I purchased from a previous group member.
I'm guessing you bought Wayne's engine, or maybe Gordon's? Both
were modified by RX-7 specialties. I think I can put my hands on a set
of mods that each of these had.
I have one of the 13b’s that was (as I was
told) part of a group purchase (members of this group) from a company called
RX7 Specialties out of Canada.
I don't know of any group purchase, but I
do have one of these engines. Below is pasted from a message that I sent
someone back when I bought mine. It explains where the engines came
from.
First, Mazda will sell brand new engines to
anyone who orders at least 120. That's really more engines than the
average person can use, so these "new" engine deals are pretty
rare.
These engines were destined to be used
by the natural gas, rather than oil business. It seems that some
natural gas is contaminated, and is called "sour
gas". The best I understand, you can't avoid getting
some bad with the good. The problem is that the contaminants in sour gas
is toxic, and poisonous in high enough quantities. The gas
company must not be able to filter out the contaminant, or it's just
not feasible to do it, because they end up with a certain quantity of
sour gas that they have to get rid of. If it were up to the gas
company, they would just burn it off, but the environmentalists won't let them
do that. They're only allowed to burn off (flare) a certain amount,
and they would have to pay to have the rest disposed of. The
loophole in the rule is that it can be burned if it's being put to some
productive use. Enter the rotary. The gas company realized
that they can burn this sour gas in rotary engines, and
run generators. They use the electricity for their needs, and any
extra is sold back to the power grid. Amazingly, they turned
something they had to pay to dispose of, into something they can make
money from. To give you some idea of the scope of this, each engine
is running a 75 kva generator 24/7, and the company that's buying these engines
wants a contract to be supplied with 900 (!!!) more engines.
Specifically, the engines are running at
3600 rpm, under a fairly heavy load. The company used to
use 454 V8 engines, but the sour gas eats the valves up and they
don't last long. For sour gas use, these rotaries
are modified for durability with ceramic apex seals, ceramic coated
rotors, and additional hardening of the rotor and
side housings. With these modifications, the engines show zero wear
on the apex seals, and less than one ten thousandth wear on the side seals,
after 3000 hours of operation. One engine ran 16,000 hours,
which is about 2 years of continuous operation. Others are as
high as 8000 hours, but they don't know the average hours of
operation before failure. Lest you think these engines
are cared for in any special way, realize that they run 24/7, and only
stop for oil changes. Also, they don't run oil coolers! They just
run a bypass hose were the cooler should be, and they're just sitting out
in the open running...all over the countryside.
I am especially looking for info on the ceramic apex
seals that this engine contains. I would also like to discuss the engine with
others here on the group that bought them.
I ordered my engine "as is", so
they shipped the engine without doing anything to it. I wanted the
ceramic seals, but since I was going to run a turbo, they advised
against them. They said the seals would not withstand turbo
usage. The story was that they had these ceramic seals specially
made, which is why there were so much cheaper than most. Hard to say
where they really came from.
The only problem with these engines is
that Mazda test ran them, then didn't drain the water. After a couple
years of sitting around, they form some layers of rust and crud in the
water jackets. Since yours was modified, you should be good to
go. Mine eventually got sent to Bruce Turrentine for 9.7 rotors, porting,
and mods, so it got cleaned out there.
Hopefully, that helps some.
Rusty (still too windy, tomorrow should be
better)
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