Paul,

   Just a thought but has anyone looked at the marine outdrive couplers.
   They turn at engine speed and handle 260HP connected to a prop.  I saw one
   today at a buddys house.  It was a 17 tooth spline about 1"OD.  The hub was
   about 4-1/2" diameter.  The bolt pattern is the same as the rear of the
   engine crankshafts.  The engines used are Ford,GM (small block and big
   block) Volvo and anything else used with a Mercruiser, Alpha, or Bravo
   drive system.

   The space between the splined hub and carrier are filled
   with vulcanized rubber.

   I got the attached photos from E-bay listings as a
   sample and there are pages of them.  Some are $99 new some go up to $189.
   LOW polar moment of inertia.  If you want more flex for a small engine just
   drill holes in the rubber section.  The pilot bearing is in the crankshaft,
   just a clearance hole thru the coupler.  Splines are about 2" long.  I am
   reluctant to add options since we are discussing several already so if you
   preffer you don't have to post this..  I just thought it looked like a nice
   piece.


George,

I think I found the input shaft.

Are all of these 1 inch diameter standard spline?

What worries me is what happens if the rubber fails.
Is the prop totally disconnected?

Paul Lamar



Paul

One suggestion if you design around the marine rubber coupling, in case the rubber fail you can
built one disk with several pins who be bolted between the both flanges and the other disk on the
spline shaft with bigger holes lined with the other disk pin but those holes have to be larger for
the damper travel space or you might have an other idea..

There is a good supplier of several coupling and damper bushings.
http://bpi.ebasicpower.com/p/MAL9-72505


Jean Prudhomme

-- That might be OK starting from scratch but the the problem is; Tracy used
a auto TX spline that does not fit any marine coupling. That would mean
the input shaft would have to be redesigned. Not practical at this time.

Paul Lamar

                       
Look at the bottom of the page this supplier sell a spline shaft for aligment of the engine do you think it can be se, i suspect i could be made of mild steel???Anyway i found the dimentions is 612" at the buttom and 4 5/8"dia at the top and 2 3/4 high,if this can be useful to youI check on the RX-8 flexwheel it have a 6 3/8 dia flat surface but it will need a spacer ring for the flexwheel bolts head thickness.


Jean Prudhomme