I am looking for these dimension from the flywheel 13-b RX-7 if someone
  have one on hand uninstalled i would really appreciate those informations
  see photo

  Jean Prudhomme

 Which dimensions? hole spacing? Diameter? Hole size? How exact do you
 need... I happen to have one off the plane right now :-)
 -- David Leonard
 Dave you are insured. Sky Smith had the info on you. You are famous.
 As far as I can tell you can fly the RV4 anytime.
 Apparently two successful off airports counts for a lot :)
 I need a medical and and bi annual. Both have recently expired. I
  got them
  for
 flying in Oz.

 Paul Lamar


 Hi David i will need all holes diameter and holes circle so i can
  compare
  with
 the RX_8 flywheelThank's for your assistance


 Jean Prudhomme


 Jean, I received the damper plate today. All is well. Thanks.
 If someone hasn't already given them to you, I picked up my RX-7 flex
  plate from
 the hangar today. I will measure it tomorrow if you still need them.
 C. Smith


  C. Smith Thank's for your response of received the damper plate,yes i
  still
  need the holes dimensions on the RX-7 flywheel just to compare if
  both are
  interchangeable, but i found an idea to use the RX-8 flywheel and the
  standard Tracy damper but Paul recommend 4130 instead of aluminum
  plate but
  it will add a few pounds, you see the rx8 one  is design differently
  then
  the rx7 with those big holes away of center holes and closed to the ring
  gear and by using a bolted plate to the original holes 12mm the Tracy
  damper
  plate by attaching the rubber bushing holes and are line up with the
  rx8 big
  holes for the bolts head clearance.There is a sketch for this additional
  plate no welding and no balancing i guess it worth to try.


  Jean Prudhomme

  Jean,

  The center 6-bolt pattern is the same for the RX-7's and the RX8.  But
  that
  is not the whole story. There are 2 different fly wheels (use with manual
  transmissions) and 2 different flex plates (used with automatic
  transmissions).  Divided thus:

  "non-turbo" flywheel - used with all manual n.a. RX-7s  This is smaller
  diameter than:
  "turbo" flywheel - used with all manual turbo RX-7s and all manual RX-8's
  RX7 flex plate - used with all auto RX7's
  RX-8 flex plate - used with all auto RX-8s (and there is a cosmo flex
  plate
  as well)
 -- the flex plates require the appropriate counter weight and that
  supplies the 6-bolt holes
 -- The fly wheels have the counter weight built in.. unless you are
  using
  an aftermarket flywheel, in which case most will bolt up to the counter
  weight.  The aftermarket flywheels come in many different weights and
  materials

  Tracy used the RX-7 flex plate and his damper plate will not directly
  fit on
  the RX8 flex plate or either of the flywheels.  The flywheels put the
  ring
  gear in different locations from each other, with the n/a RX7 being
  smaller
  than the Turbo RX7/RX8.

  But I have not been able to figure where the RX7 auto flex plate puts the
  ring gear in relation to the flywheels (though it seems to have the same
  number of teeth as the turbo RX7/RX8 flywheel)

  Tomorrow afternoon I will be able to get to the hangar and let you
  know the
  size of the -7 flex plate relative turbo flywheel.  Since the
  flywheels are
  already really beefy, I was hoping there might be an easy adaptation
  of one
  that would put the ring gear and damper place in the right spot...but that
  is seeming more and more unlikely.


 Paul

 When you decide a final design, collect all interested as a group, send
 them here and I'll get it done.....

 If it does not require lots of machining, I'll do it for free..But if it
 does need to be charged, it will be reasonable to all......

 The bolt pattern on the end housing is a bit stingy on the number of
 bolts to attach and the very asymmetrical distance between
 holes....10.5" inch gap spanning the starter position and 9" in span on
 the bottom distance......any future aluminum end housings should include
 a better arraigned pattern to handle loads in all directions.  Just a
 thought..


 jeff

 It is up to Dave. He will abuse it until it breaks. Just kidding Dave :)
 He is chief R&D engineer on high power rotary installations.

 I agree on the bolt pattern Jeff.

 Paul


 Jeff,  I agree about the lack of bolts. I am carving patterns as shown in
the two attachments. One is a rear housing with extended flange rather than
spacers to mount your motor plate directly. The second attachment is a
center housing which makes it easier to see the four 5/8" tie rods that go
through the entire block and motor plate. The rest of the bolt holes in the
belhousing rear iron  (aluminum actually) perimiter are all for attaching a
PSRU plate. The layers for this rear iron are carved but not glued up yet.

george grimes