Paul, do you or anyone on the group remember the change in crankshaft resistance after torquing down the RD 1C 12" an4 bolts at final assembly?

The assembly instructions show a trial fitting without the 5 1/8 inch ring gear spacer o-ring. This worked well on my unit, with the crankshaft turning easily by hand.  However I found this oring was missing from my unit.

Tracy's specifications are for a 5 1/8 inch outside diameter and 0.190 inch thickness, which  corresponds to an AS568-351 (3/16" thick). I ordered some of these,  but found that the actual thickness is 0.21 inches, not 0.190". I cannot find any metric or other equivalent size that exactly matches the 0.190 specification.

When tightening down the drive bolts to the final torque, the resistance to turn the crank shaft roughly doubled. I can still detect just a little bit of backlash play, but the torque required to turn the crank shaft without spark plugs installed is approximately 20 foot pounds.  It appears this is due to the resistance of the ring gear pressing on the O-ring against the adapter housing.

Does anyone know if this amount of resistance is normal, or perhaps Tracy was using some o-rings that are exactly 0.190 inches in thickness?

Thanks!

Scott Gettings


I assume that is the late  one that does away with the torque damper.
I have no experience with that one. Send me a dwg or sketch if you can.
A picture or two would also help.

Typical of O-ring dimensions. It gets real critical when you are dealing with the rotor housing
O-rings. Too big and it will crack the cast iron.

I this case it's not that bad.

Paul Lamar



The Rotary Engine free News Letter. Powered by Linux. If you want off
the list PLEASE let me know and I will remove  you.  ACRE NL web
site. http://www.rotaryeng.net You Tube http://tinyurl.com/beqqxas
Copyright 1998-2017 All world wide rights reserved.