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From: Jim Brewer <alpha@concordnc.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Date: Fri, 20 Aug 2004 18:00:11 -0400
Message-ID: <200482018011.636693@alphasys>
In-Reply-To: <list-372325@logan.com>
Subject: Re: [FlyRotary] Initial teardown questions...
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On Fri, 20 Aug 2004 08:55:00 -0500, David Staten wrote:
I have completed tearing down a 13B 2nd gen turbo and have pretty much
cleaned up the rear side housing, rear rotor housing and rear 
rotor....
with the other large parts on a soak cycle... I am intending to go 
ahead
and use Tracy's "Master Rebuild" kit with replacement of all the
internal seals, springs and O-rings.. partially because when the 
engine
was disassmbled, the case split in an unexpected fashion and some of 
the
side and apex seals came out in an uncontrolled manner, to the point I
am not sure exactly where they originated from... I know which side of
the rotor they came from, but not which "groove" they belong in with
certainty.
 
After cleaning the rear rotor, I observed a small "ding" in the face 
of
the rotor adjacent to the apex seal groove.. I am estimating it is 
less
than 1 mm wide and minimal in depth. It will catch a fingernail. I was
unable to take a picture of good enough resolution (3.1 mpix camera) 
to
show the blemish.. but my question (first of many) is.. what are the
limitations to surface anomalies on rotors with regards to scratches,
dings and the like?
 
Also, are there any limitations on having the housings bead blasted to
remove water jacket corrosion and external grime? If permissible, any
material to use or not use?
 
Finally, when I do get around to reassembly, something I am not 
ENTIRELY
clear on is determining top-dead-center. I see how the front e-shaft
flange bolt pattern is unique and limits installation to only one
possible way with regards to the timing marks on the eshaft pulleys, 
but
what is the trick to aligning the eshaft with the rotor? Is it truly
just as simple as having a rotor apex at one of four positions when
reinstalling? If not, what is the rotor apex position associated with
TDC (perhaps determined after reassembly, if need be)?
 
Dave Staten
partner in Velocity N17010 (reserved)
Mazda 13B 2nd gen turbo rebuild


Dave,
I cleaned my rotors and front, intermediate, and rear housings with 
foaming Easy-Off oven cleaner. Stuff the eccentric shaft opening in 
the rotors with plastic to keep the cleaner off the bearing.  Duct 
tape would also work...be creative...just keep the lye cleaner off the 
bearing.  Scrub everything with a green scrub pads.  Have your can of 
carb cleaner to soften up the gunk in the grooves.  Xacto knife with 
tip broken to clean out side seal grooves.  Apex seal grooves can be 
cleaned out with old apex seal.  Go slow and remember "Cleanliness is 
next to Godliness" Be through.  When you think you have all the gunk 
you are probably half done.  Wear gloves and have plenty of fresh air.

I would use a Dremel tool with a sanding drum to smooth out the gouge 
on the face of the rotor.  Keep the Dremel tool with the drum handy 
because you will need it to grind the side seals to tolerance, 2-6 
thousanths.  Bruce Turrentine told me that trick.  GO VERY SLOW doing 
this.  I got close and used a whet rock (small pocket knife size) to 
hand finish.  The angles are about 45 degrees to match the corner 
seals.   Let the adventure begin! Zoom a Zoom!

Jim Brewer
Albemarle, NC