In a message dated 12/25/2006 7:46:27 P.M. Eastern Standard Time,
BMears9413@aol.com writes:
Someone mentioned checking the timing by counting the teeth on the
flywheel. I've not read that before. could someone enlighten me on this. I
wouldn't mind double checking my timing marks with this method.
Thanks
Bob Mears
Supermarine Spitfire
With the battery disconnected, remove the leading plug from the front
(number one) rotor housing. The one right behind the belt pulley. If you have a
good feel of things, wet your thumb and place it over the hole and rock the
engine over suspected TDC. With a bit of practice you can get TDC on the button
that way. Or, screw some food grade clear plastic hose (Sears) into the plug
hole. Place the end of the hose against the under side of your tongue, and rock
the engine back and forth over suspected TDC. Or, pour some ATF into the same
tube, but let it sag so as to form a "P" trap. Like the drain under the sink.
Rock the engine over suspected TDC, just a degree or so in each direction,
and look for that location where the ATF does not move. That is TDC.
Or take out both plugs. Place the engine at suspected TDC. Make up a
pointer that points to the flexplate teeth at some location where you could see
it with the engine running. Turn the engine backwards until you see an apex seal
in the bottom plug hole. Center that seal in the center of the hole. Make a
chalk mark on the tooth next to the pointer. Look in the top plug hole.
Turn the engine in the forward direction until you see an apex seal in the
center of the upper plug hole. Mark the tooth next to the pointer.
TDC is half way between those two chalk marks. Count back to the TDC tooth
from both marked teeth to be sure that you are looking at the same tooth.
Do it a few times and play with the pointer so as to come out pointing at a
full tooth or between two teeth if you like that better. Once you are happy
that you have repeatability and are accurate, paint the TDC tooth red.
Now count the teeth on the flexplate. Divide into 360 to get degrees per
tooth. Turn the engine backwards from TDC the number of teeth that will produce
the timing you want. Say 24 degrees. That might be about 12 or 14 teeth.
Paint the full advance tooth bright white. You can paint other teeth other
colors to indicate other amounts of advance if that is helpful. Make a paint dot
on the bell housing and indicate what lead each color represents.
Now without turning the engine at all, make up a steel permanent pointer
that points at the total advance tooth. Bolt it on. Safety wire it. Aluminum
pointers fatigue to death and vanish.
Lynn E. Hanover