" Joe,
There was a posting some time back explaining how to find TDC, but a search of my archives didn't turn it up. I think it was Lynn Hanover who explained how to do this, but I won't bet my life on that. This process worked for me on my 20B. So, I'll try to explain it for you.
Remove spark plugs for easy engine rotation. On #1 rotor (nearest front cover) rotate the engine in the normal direction until you can see an apex seal in the exact center of the trailing spark plug hole. Mark a convenient tooth on the flywheel. (Helps to make a pointer) Then rotate the engine backwards until you can see an apex seal in the exact center of the leading plug hole. Make another mark on the flywheel using the same reference point as before. Now count the number of teeth between the two marks and place a mark on this tooth. Rotate the engine back again to align this tooth with the pointer. This will be TDC. Now you can mark the crank pulley at the pointer on the front cover, or just use the this new mark on the flywheel instead.
Mark S.
Bill B
Make the pointer so it can be replaced into the same place again and again, or make it part of the engine.
This will get you to TDC within a degree or so. Once you have a TDC tooth on the flexplate marked,
(Or valley between two teeth) count the teeth on the flexplate and divide into 360 to get the number of degrees per tooth. Put the TDC tooth or valley under the pointer on the rear iron (the one with the reduction unit) and turn the engine backwards the number of teeth to get to whatever degree of advance you need to mark. I think Tracy needs a mark at 35 degrees. Normally I run 25 to 27 degrees total at 4,000 RPM.
So mark the teeth with colored paint. Say red for TDC. Yellow for your correct timing say 25 degrees, and green for that set up number at 35 degrees. The 35 is for setting up the controller and you can adjust it back to whatever you want.
If the colors are difficult to see, add white paint to each side of your collors.
Anything between 20 degrees and 27 degrees is fine. The rotors operate at 1/3 the speed of the crank so actual timing at the rotor is very modest, so 27 degrees is 9 at the rotor and so on. Even 20 degrees on low octane fuel is good up to 9,000 RPM.
Lynn E. Hanover
Check under the back seat.
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