OK all you 20B guys (Tracy, Robin, Bob, Barny, etc.),
How do you set the initial timing of the CAS if you have no timing

marks

on the Damn pulleys or you don't know what degree from TDC a mark
represents???  Also, what exactly does TDC mean in a rotary????  I'm
assuming that the timing is set the same way as on a 13B but I don't

know

for sure.

HELP !!!
Thanks again,
Don Mitchell

Since we did not have any 20B guys chime in I will give it a stab.
Let us assume the exhaust manifold is off the engine. Look through
the exhaust port and turn the engine clockwise until the front rotor

apex

seal
just passes the exhaust port.  Rotate the engine plugs up. Remove
one spark plug on the front rotor. Fill the combustion chamber with

oil.

Jiggle the e-shaft back and fourth rather quickly and add oil until

the

oil level
comes up to the top of the spark plug hole and starts to go back down
as you continue to rotate the e-shaft back and fourth.

That is top dead center. Mark the front pulley or the flywheel. If the
seals
are leaking badly this won't work.  A clear plastic tube inserted in

the

spark plug hole somehow will work even better with this trick.

Paul Lamar

Obviously Tracy has done this for his 3 rotor computer. I have red and
yellow timing marks on my innermost 20B pulley as well. Also, you can
take off the distributor rotor cap and watch that pass the pickup.....
I seem to recall this discussion with Tracy long ago.
[Marc Wiese]

Tom Kendall replied:

Yes Marc, but....

How do you know you've got the accessory gear/distributor gear mesh right
when reassembling?  I haven't gotten to that part in Bruce's video yet.
This is critical to ensure that the pickup fires the ignition at the right
time.

I suppose that if the folks at Mazda were REALLY clever, the pitch of the
accessory gear is just right so that any mesh will work.  But I haven't run
into anything that convenient before in an engine.

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site. Copyright 1998-2002 All world wide rights reserved.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org