Jay,

   The 20B utilizes a split shaft.  You're going to have to separate
it in   order to disassemble the engine.  Bob Darrah built a
splitter tool from a   threaded shaft and a 1" thick bar of steel.
 The threaded shaft will need   to   match the threads in the #1
lobe on the crank, 18mm if I recall   correctly.   Thread the shaft
into the lobe, slide the 1" bar over the other end of   the
 threaded shaft until it fits snug against the nose of the eccentric,
 put   a   nut on the threaded shaft to tighten it all down.  You
may want to use a   soft aluminum or brass spacer so you don't
bugger up the end of the   eccentric.  Tighten the nut until it
cocks the 1" bar a little, then tap   the   other end of the bar
with a hammer and it should come right apart, at   least   that's
how it has worked for me twice.  Now you can finish disassembling   the
   engine.  Remember the sequence for when you are ready to re-
assemble it.

   Mark S.

  Mark--do you have a photograph of the 3-rotor eccentric separation
tool  installed on the eccentric?

  Steve Beckham

   Steve,

   Yes, see the last picture in the group.  The TR (threaded rod) screws
  into
   female threads in the #1 lobe (the removable one).

   I should have mentioned that the picture doesn't show the BN (big
nut)   that gets threaded onto the other end of the TR.  The purpose
of the BN  is   to lock the BB (big bar) down against the end of the
e-shaft.  I  recommend   you put a piece of softer material (like
aluminum or brass) between the  BB   and the e-shaft to keep from
damaging the threads.

   Once it is assembled, you take a BH (big hammer) and smack the
  unsupported
   end of the BB.  The #1 lobe should pop right off.

   Mark S.

   I'm having a heck of a time finding an 18mm bolt with 1.5mm pitch
long   enough to use on getting the E shaft split. Looks like I'll
be   fabricating/jury rigging/welding something.

   Jay

   Welding. Not all bad. The loads are not that high.

   Paul Lamar

   Jay,

   That's the problem I encountered.  As I stated earlier, the one shown
in
   the
   picture was built by my machinist friend Bob Darrah.  If you take
a   close   look at the threaded rod, you can see that he turned
down the larger   diameter and threaded it for 18mm.

   Being a welder (not a machinist) I had planned on welding a bolt
to a   threaded rod.  Paul's correct, the loads aren't that great.

   Also, make the hole in the BB a little oversize so it can move a
little.

   Mark S.

   Tiffany Perez

   Spahr Metric, Inc.

   421 McGhee Road

   Winchester, VA 22603

   PH: 540-678-3815 Ext 101

   Fax : 540-678-3819

   I just ordered an 18 x 1.5 mm threaded rod from the company
above. It's   three times the length I need but it's only $22. I
thought I'd mention   it   in   case any one else was looking for
parts to separate the E shaft   extension   with. They have access
to shorter bolts of that size but you have to buy   a   box quantity.

   Jay

  Jay,

  Good info on the 18mm all-thread.  Hope you ordered a couple of
18mm nuts  too.

  Do you have a chunk of 1" thick bar stock?  It should be approx.
10-12" x  3".  You'll also need a drill press (or torch) to
drill/cut a big hole in  the 1" bar stock.

  Mark S.

  Mark,
  Yes I got nuts to go with the rod and I also have a piece of steel
   channel
  stock. I thought it might be as stiff as a thicker piece of rectangle
  stock.
  I already drilled a slightly over size hole in it, with a $20
drill bit  I'll  probably never use again.

  Jay

   Jay,

   If you were local, I would loan you this one.  On the brighter
side, now   you'll have your own puller, just in case you ever need
to go through your   engine in the future.  Let's hope you never
need to use it again.  Good   luck!

   Mark

   Slightly off topic question.
   With this email newsletter format, is there any kind of archive that
   someone
   could search through, rather than asking questions that some of
you more   knowledgeable guys may be getting tired of answering?

   Jay

   Other than the web site nothing. I don't mind as things change
and we are   constantly getting new readers. For new readers please
read the entire web   site first and then ask questions. I notice
some people don't read the web   site.   Not you Jay :) We don't
have anything on overhauls other than a link to the   shop manuals.
Unfortunately there is no english shop manual on the 20B that   I
know about. Videos yes but no printed 20B shop manuals. After a 11 years
   I am still learning. I have a 20B but it has not been disassembled.

   If I get some questions that are not covered by the web site I
will update   the web site. I average some kind of update about once
a week. Some times   it is just to add stuff to the for sale section.

   Paul Lamar

   I'm still trying to get the 20B E shaft extension apart.
   I have pretty much all the torque I can get on the nut with no results.
   I attached some photos, does it look like I'm doing this
correctly?   I want to  make sure before I put a pipe(for leverage)
 onto the wrench I'm   torqueing the nut with.   The black piece
between the big bar and the end of the shaft is there just   to
protect the threads and spread the load.

   Jay

   I would take the rubber out of there and replace the large screw
in the end   of the   e-shaft to protect it. Take up the tension
again and smack the iron angle   with a hammer.   The shock should
cause the e-shaft to vibrate and come apart.

   The angle iron might not be stiff enough to do this as the guys
have been   using a bar of steel instead of angle iron.

   Paul Lamar

Jay,
The nut doesn't have to be all that tight, just tight enough so that
the steel bar isn't sitting flat on the end of the e-shaft.  Just to
be perfectly clear, you strike the end of the bar opposite the nut/threaded
rod.

I have to agree with Paul to replace the rubber with a piece of
aluminum or brass.  I would bet that the angle iron isn't stiff
enough for the job.  It may also be too long and thereby absorbing
much of the energy of the hammer blow.

Also, you want the threaded rod as close to the C/L of the e-shaft
in order to get the most leverage for when you strike the opposite end.

Mark

Thanks for everything so far gentlemen. That "plastic" was a metal bracket
but I removed it and used the E shaft nut instead for my latest
attempt. I also cut my angle bar into thirds, and used two pieces
one on top of the other. Not as stiff as a single piece I'm sure but
presumably better than before. In any case it still didn't work. I
banged on it with a regular hammer and a dead blow hammer, my
extension hasn't even budged. Either Bob with the spitfire is be
leading a charmed life, or my extension is welded on. :)

I'm going to try and pry it off tomorrow.
http://www.wut2c.com/Knowledge/Automobile/mazda_20b_rebuild_tips.htm

If that doesn't work, I'll officially be desperate.

Jay

You need the thick steel bar Jay. Two angles back to back damp out
the vibration. Also a carpenters hammer usually does not work. It
does not trigger the intense vibration you need. Try a ten pound
sledge. Also warm it with a butane torch. I don't recommend a dead
blow hammer. You need that metal to metal shock. We have the same
problems with flywheels. The answer is always the same. A larger hammer.

Paul Lamar


Wasn't it Truman who said "walk softly and carry a big stick"

Dale Davies