-----Original Message-----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Thu, Sep 16, 2010 5:05 pm
Subject: [FlyRotary] Re: Timing

Brian,

I found the email explaining how this process should be done. Charlie= was correct in that you use both leading and trailing plug holes. <= /div>

Mark

<snip>

" 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 Hano= ver 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 fo= r you.

Remove spark plugs for easy engine rotation. On #1 rotor (nea= rest 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.&nbs= p; 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 nu= mber 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 engi= ne.

This will get you to TDC withi= n 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 degree= s total at 4,000 RPM.

So mark the teeth with colored= paint. Say red for TDC. Yellow for your correct timing say 25 degrees, an= d 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 an= d 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 roto= r and so on. Even 20 degrees on low octane fuel is good up to 9,000 RPM.

Lynn E. Hanover<= /div>

Check under the back seat.

<snip>

On Thu, Sep 16, 2010 at 5:16 PM, Charlie England= <ceengland@= bellsouth.net> wrote:

Hmmm...

I've seen a variation on that technique for piston engines using a probe= in the spark plug hole, but I'm having a hard time seeing how it would wo= rk on a rotary. If you do it using just one plug hole, wouldn't that put= the center of the rotor face over that plug's hole? Or is that TDC, or is= there some geometric characteristic of the rotary gear train that moves= the TDC point?

Would the technique work if you used *both* plug locations, & approach= ed one in the forward direction & the other in reverse rotation?

Charlie

On 9/16/2010 1:46 PM, Mark Steitle wrote:

Brian,

I was curious, have you verified that the timing mark you believe to be TD= C 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 (chec= k archives). Basically, you remove the leading plug on #1 rotor, rot= ate 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). Th= en 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 betw= een the two marks and that should be TDC. Check that it matches the= mark on your pulley.

Mark S.

On Thu, Sep 16, 2010 at 1:33 PM, <bkt= rub@aol.com <mailto:bktrub@aol.co= m>> wrote:

I've got a 74 x88 catto. The Co was a result of the band clam= p not
sealing completely, but I was going to change to 321 or Incon= el
any way, so I figured I'd do it now and be done with it. I wa= nted
to be absolutely sure my timing was correct before going any<= br> further down the tunig road. I checked the timing yesterday,= and I
was getting the leading plug firing about 10 degrees in advan= ce of
those two timing marks lining up at 1400 rpm. I adjusted it= so
that it is now dead on at 1400 rpm. I set it there as a refer= ence,
it's easy to change in Mode 8. There's no reason to go any fu= rther
in the tuning department unless I can be assured that the tim= ing
is correct. I've got a factory manual, but have not found any=
reference to the timng marks or exactly what they signify. Brian Trubee

-----Original Message-----
From: Don Walker <drw= alker@gbis.com <mailto:drwalke= r@gbis.com>>
To: Rotary motors in aircraft <flyrotary@lancaironline.net
<mailto:fly= rotary@lancaironline.net>>
Sent: Thu, Sep 16, 2010 11:14 am
Subject: [FlyRotary] Timing

Brian,
Timing is one of the few things I didn't have to mess= with. Once
all the other problems were taken care of and the CAS was spa= ced
correctly, the engine started and ran fine. What a day! I am= using
the EC-2 default setting for the renesis as programed by Trac= y and
have not even paid much attention to it or even checked it.= Good
luck on your next flight. I assume you are using the EM-2 and=
EC-2. What prop are you using? You make a good point on check= ing
for CO. I just have one of those stick on cards and should bo= rrow
a real meter as I am running SS flex tube also.
Don
RV-8 renesis 76/88 cato

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