X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-mb02.mx.aol.com ([64.12.207.163] verified) by logan.com (CommuniGate Pro SMTP 5.4c2o) with ESMTP id 4886150 for flyrotary@lancaironline.net; Tue, 01 Mar 2011 02:16:57 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.207.163; envelope-from=Lehanover@aol.com Received: from imo-ma04.mx.aol.com (imo-ma04.mx.aol.com [64.12.78.139]) by imr-mb02.mx.aol.com (8.14.1/8.14.1) with ESMTP id p217GFVu027544 for ; Tue, 1 Mar 2011 02:16:15 -0500 Received: from Lehanover@aol.com by imo-ma04.mx.aol.com (mail_out_v42.9.) id q.1004.8e2f8f8 (55730) for ; Tue, 1 Mar 2011 02:16:10 -0500 (EST) Received: from magic-d16.mail.aol.com (magic-d16.mail.aol.com [172.19.155.132]) by cia-md03.mx.aol.com (v129.9) with ESMTP id MAILCIAMD035-d9b24d6c9d3a2e9; Tue, 01 Mar 2011 02:16:10 -0500 From: Lehanover@aol.com Message-ID: <3b301.623eddaa.3a9df73a@aol.com> Date: Tue, 1 Mar 2011 02:16:10 EST Subject: Re: [FlyRotary] Re: Steve Boese TDC Finder To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_3b301.623eddaa.3a9df73a_boundary" X-Mailer: 9.0 Security Edition for Windows sub 5382 X-AOL-IP: 72.187.199.116 X-Spam-Flag:NO X-AOL-SENDER: Lehanover@aol.com --part1_3b301.623eddaa.3a9df73a_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 2/28/2011 1:48:13 P.M. Eastern Standard Time, echristley@att.net writes: Al Gietzen wrote: >> Al > >> > > > I have been doing this since 1980, and that last one lost me. Any method used must involve both the leading and trailing plug holes. Any method that uses sightings of apex seals in those plug holes will be off between 4 and 9 degrees (advanced) because the plug holes are both located higher in the housing than neutral. Also the distance between plugs is different in various housing years. This is good for an approximation of TDC only. Good for first start and dropping in the distributor or crank angle sensor. The pulley should be marked with an accurate TDC and at least the maximum total advance, or lacking that, the TDC mark and an adjustable timing light. Has the knob on the back. Costs a lot more. You rev the engine up to test RPM, say 6,000 and turn the knob until the TDC mark is under the pointer. Look at the pointer on the back of the timing light it is pointing at your total advance at 6,000 RPM. Use any minimum volume system to find an accurate TDC. 20 to 24 degrees is plenty of advance unless have to use high octane fuel all of the time, then 26 to 27 degrees is fine. Mark the starter ring teeth with different color paint dots for TDC and maximum advance. Buy an inductive (Clip on) timing light and practice using it. It was 80 today in Zephyrhills. I flew my Super Cub and BF-109 before the wind picked up around 10:00. Not a single cloud to be seen. The sky divers were up all day. Lynn E. Hanover --part1_3b301.623eddaa.3a9df73a_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 2/28/2011 1:48:13 P.M. Eastern Standard Time,=20 echristley@att.net writes:

Al=20 Gietzen wrote:
>> Al
>
>>
>=20
>
>

I have been doing this since 1980, and that last one lost me.

Any method used must involve both the leading and trailing plug holes= . Any=20 method that uses sightings of apex seals in those plug holes will be off= between=20 4 and 9 degrees (advanced) because the plug holes are both located higher= in the=20 housing than neutral. Also the distance between plugs is different in vari= ous=20 housing years.

This is good for an approximation of TDC only. Good for first start= and=20 dropping in the distributor or crank angle sensor. The pulley should be ma= rked=20 with an accurate TDC and at least the maximum total advance, or lacking th= at,=20 the TDC mark and an adjustable timing light. Has the knob on the back. Cos= ts a=20 lot more. You rev the engine up to test RPM, say 6,000 and turn the knob= until=20 the TDC mark is under the pointer. Look at the pointer on the back of the= timing=20 light it is pointing at your total advance at 6,000 RPM.

Use any minimum volume system to find an accurate TDC.

20 to 24 degrees is plenty of advance unless have to use high octane= fuel=20 all of the time, then 26 to 27 degrees is fine.

Mark the starter ring teeth with different color paint dots for TDC= and=20 maximum advance. Buy an inductive (Clip on) timing light and practice= using=20 it.

It was 80 today in Zephyrhills. I flew my Super Cub and BF-109 before= the=20 wind picked up around 10:00.

Not a single cloud to be seen. The sky divers were up all day.

Lynn E. Hanover

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