Bill, I ported my turbo block using the
Racing Beat (MazdaTrix) port template and carbide bit grinder as well as a valve
porting sanding kit (you know with all the sandpaper grinding/smoothing burrs).
You get the outline of the port on a piece of metal which you then have to cut
out (at least you did when I go mine), but it does have two holes in it for
alignment using the dowel pins of the rotor housings. Paint the iron side
housing with the “blue” machine drawing ink and then use the
template to draw the outline of the port.
Remove the template and I recommend
covering the side plate with a layer or two of duct tape (or something similar)
around the area you intend to grind – the carbide bit can make a nasty
burr across the face if it gets away from (don’t ask me how I
know). I experimented with a junk side housing until I felt
comfortable. I did this on a 91 turbo block and you do need to exercise
some care not to carve into a EGT port that runs close to the intake port in
the casting.
This porting changed my timing from the
stock 32 IO and 50 IC to 25 IO and 60 IC. It made a difference of 200 –
250 + rpm static on my engine, so I considered it well worthwhile. This
91 street ported turbo block turns 6000-6200 static (depending on OAT) swinging
a 74x88 prop with a 2.85 gear box.
Ed
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Bill Eslick
Sent: Monday, January 26, 2009
10:20 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Frying
pan into the fire....Arrgh
I sure hope somebody comes up with an explanation for coolant in the
rotor housings, as I can't find one! I tore down my engine because of
that, and could find NO o-ring leaks. If it leaked, it didn't leave any
evidence. The system would hold 15 psi pressure for a week or so, but
would slowly leak into the rotor housing. Up to temp, it would
blow air into the coolant system (equal opportunity leak).
Didn't find the coolant leak, but did find about 3/4" of one of the side
seals missing. Now I am gathering parts to put it back with '91 rotors
(need a rear counterweight), and looking at street porting. Does
anyone know if there is value in street porting if 6000 rpm is the highest you
will see? Lynn??
Bill Eslick