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Date: Fri, 20 Aug 2004 08:55:00 -0500
From: David Staten <Dastaten@earthlink.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Initial teardown questions...
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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