You can get an air hold, essentially a spark plug hole adapter that goes on a compressed air hose, for about $6 at NAPA. It's used to hold a valve in place while you change the valve seals. You can use it to find TDC by putting it in the plug hole, running a tube  to it and putting the end in a jar of water or oil. Turn the engine slowly until the point where the bubbles stop and the water just starts to go up the tube. That's TDC.

 

Brian Trubee

-----Original Message-----
From: dlomheim@aol.com
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Fri, Feb 25, 2011 8:10 pm
Subject: [FlyRotary] Steve Boese TDC Finder