Mailing List flyrotary@lancaironline.net Message #52134
From: <Lehanover@aol.com>
Subject: Re: [FlyRotary] Re: Timing
Date: Thu, 16 Sep 2010 21:46:01 EDT
To: <flyrotary@lancaironline.net>
In a message dated 9/16/2010 2:47:32 P.M. Eastern Standard Time, msteitle@gmail.com writes:
I was curious, have you verified that the timing mark you believe to be TDC is actually TDC?  I recall it being mentioned before that you can't rely on the timing marks on the pulleys as sometimes pulleys get swapped from one engine to another and may not match up correctly.  I feel it is worth checking.  Lynn H. has described how to locate TDC (check archives).  Basically, you remove the leading plug on #1 rotor, rotate crank until you see an apex seal in the center of the hole, put a mark on the flywheel (use a temporary pointer for a reference point).  Then reverse rotation until you see another apex seal in the center of the hole, put a 2nd mark on the flywheel.  Now split the difference between the two marks and that should be TDC.  Check that it matches the mark on your pulley.  

Mark S. 
MMMM, that would be real close, However.
 
Remove all of the spark plugs.
 
Turn the engine in the direction of normal rotation until you can see an apex seal in the center of the trailing plug hole of the number one rotor housing. The rotor housing furthest from the prop. The upper plug is the trailing plug.
Removing the plug will reveal the hole.
 
Mark a flywheel starter tooth under your temporary pointer. Use welding wire or a coat hanger for a pointer, so you can bend it as needed. It needs to be well mounted and snug.
 
Once you have marked the tooth under the pointer with a paint drop, or chalk, or scrap of tape, do not move the pointer any more.
 
turn the engine backwards about 30 degrees, looking into the leading plug hole for the next apex seal to come to the center of the hole. The leading plug hole is the one on the bottom of the number one rotor housing. Once you have that apex seal centered make a second mark on a flywheel tooth or valley between teeth, whatever is under the pointer.
 
Half way between those two marks, make a third mark. This mark will be the TDC mark, accurate to about a degree. Clean the tooth with a fine file and paint it red. Count the teeth on the flexplate/flywheel.
 
Let us say that you find 106 teeth. divide 360 by 106 and get 3.39 degrees per tooth. So, for a timing mark at 24 degrees (for example) you would count off 7 teeth while turning the engine backwards. Mark whatever is under the pointer a different color than red. Make it bright like white or yellow. You can move the red dot back under the pointer. Remove the wire pointer and make up a permanent pointer to point at the red mark. So long as the engine is not turned during this process, all will be well. If you install more than one timing mark stamp what each is for on the spacer plate, with the correct paint dot by each line. 
 
Use only a clip on inductive timing light. clipped onto the leading plug wire of the number one rotor housing. 
 
Lynn E. Hanover
 
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster