Paul, I Have 19 tension bolts in my engine ,all of which are in use.
Does this mean the housings are not suitable as p-port housings.Also I
included one of my apex seals. Can you tell by the pic if it is a
factory Mazda seal or after market.
Thanks for your time, Geir
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Your engine was built by Darryl Drummond as I recall.
Darryl is highly thought off in the rotary engine racing world.
I assume it is a 13b. Darrel also builds a lot of 12A.
Later rotor housings do not have that tension bolt.
I see no reason why you need it.
That looks like one piece apex seal. That is a positive thing for our
use.
Does it look like cast iron or steel? I don't think Mazda made
one pieces seals in metal. I could be wrong. Perhaps the racing
division sold them. I do believe they made some one piece seals
in carbon aluminum however.
I hope you know where each seal came from
exactly as many racing builders adjust the length of the one
piece seals to fit. To figure this out uses a 2 to 4 inch
micrometer and measure the length of each apex seal.
Are they 2 mm or 3 mm thick? If it is an after market
seal I am sure it is OK based on Darryl's reputation.
Was there some reason you took the engine apart?
As I recall the former owner never flew it.
It looks brand new.
Hopefully you can get in touch with Darryl by calling or
emailing.
Drummond Enterprises
Daryl Drummond
3590 N. River Road
Gold Hill, OR 97525
voice: 541-582-1786
fax: 541-944-5581
fastrotary@earthlink.net
Paul Lamar ...No rotor no motor.
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Paul, The motor was built by Daryl Drummond and I had no success in the
past in trying to reach him.I took the engine apart to proceed with a
p-port intake. I wasted 3 months trying to get a little cnc work done at
a local machine shop on a standard side port intake manifold.The slide
throttle and p-port seemed like a much cleaner install. So if I
understand you correctly I can eliminate the extra tension bolt and
proceed with p-port yes.
The seal is a light gray in color and is very light weight , almost
feels like plastic. Perhaps the carbon aluminum,I'm not sure. I did
however put a piece of string around the rotor before pulling the rotors
all the way out so everything stayed as it was.
I will try to email Daryl
Thanks,Geir
Sounds like a carbon aluminum apex seal. Standard in earlier
car racing engines. Works good. Jim Mederer said they wear
initially but settle down and last a long time.
BTW fill the gap just above the unneeded tension bolt
with a shaped bar of aluminum before boring as well as the bolt hole
itself. It need not fit exactly but it will fix the small hole
problem. You can die grind it out to almost a rectangular
shaped hole which will ease the shaping of the bar. That will clean
the surface so the JB Weld will bond the bar in better.
You would then be boring through nearly pure aluminum.
This is a one time thing folks as Geir has a very
rare rotor housing.
Paul Lamar ...No rotor no motor.
Isn't this a GSL-SE housing? A couple of guys I know who have built
lots of 13b racing engines both say these are "the best". Geir, if it
were my housing, I would go with a slightly smaller port tube and keep
that extra bolt. How much space do you have between those bolt
bosses? You could bore a sixteenth inch into each boss without hurting
anything.
That apex seal looks and apparently feels like a ceramic. Is there a
ceramic coating on the ends of the springs?
Aubrey
I don't buy that Aubrey. Early four port 13B's had that bolt
starting in 1974 with the RX4.
The reason Mazda eliminated the bolt is there is no load on it
and they needed the room for the six port engines. That part of
the engine has no pressure inside it so the bolt is not needed.
That is the side of the engine where both the exhaust and intake
ports are always open so no significant pressure can be maintained
inside the engine in that area.
Here is the tension bolt pattern on the 1991 and up
engine that generates as much as 280 HP in stock turbo form
sold in Japan in 2003 with only 18 bolts. So too the RX8.
Lots of people overhaul Mazda rotary engines while really knowing
very little about them from an engineering point of view.
Paul Lamar
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