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

-

I finally had success getting the shaft split. The pry and pound method
worked and fairly easily at that.

I recently ordered both a water and oil pump from Atkins. I got to looking
this afternoon and neither of them is even close to fitting my engine. I
have parts numbers from http://cp_www.tripod.com/rotary/pg20.htm but they
don't appear to do many any good with any supplier I've found so far. Tracy
Crook told me he used a 13B water pump on his 20B and he thought the oil
pump was the same as a 13B as well.

1) Is there a way to get my engine serial number and DOM off the engine
somewhere? So far I've been unable to determine either.

2) Is there a rule of thumb for ordering 13B parts to be used on a 20B as in
year model equivalents? IOW for example 93-95 RX7 parts normally fitting a
20B. I was thinking the 20B was in production from 90' - 96' so I was
assuming 13B parts from those years would generally fit.

3) Anyone know parts numbers for the water and oil pumps from the 20B or
maybe a supplier you've used that caries them?

Jay