X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 21 Oct 2013 10:37:27 -0400 Message-ID: X-Original-Return-Path: Received: from nm32-vm7.bullet.mail.bf1.yahoo.com ([72.30.239.143] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6548823 for lml@lancaironline.net; Mon, 21 Oct 2013 08:15:40 -0400 Received-SPF: none receiver=logan.com; client-ip=72.30.239.143; envelope-from=n20087@yahoo.com Received: from [98.139.212.152] by nm32.bullet.mail.bf1.yahoo.com with NNFMP; 21 Oct 2013 12:15:05 -0000 Received: from [98.139.211.193] by tm9.bullet.mail.bf1.yahoo.com with NNFMP; 21 Oct 2013 12:15:05 -0000 Received: from [127.0.0.1] by smtp202.mail.bf1.yahoo.com with NNFMP; 21 Oct 2013 12:15:05 -0000 X-Yahoo-Newman-Id: 342859.84234.bm@smtp202.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: fBqgLVEVM1lnWSzObrLf6hMj988cJdJgYbP5RfHIAgGtsCG o6mYj9ZwsBCXinFLPYflCp91a.xBRRvMPRp4IKlLFb2ROkHMICfkmwmCOXxT XTBbi_kHQvUJwiujmKwRG0E41YfeimvckaAOhSAZXrgpryeLzlMfA_cAExbD AMY93J5lNJlrl2vjx.cpQc6bP6OyC_B8o6_ninMTnNKTFUln8EmASrecat8k 25bhRcnVFKmP7_pcOqMmKq124A_7DDmhgxIK6dqlGcCRLmHW_PUXt3cgxahF 4TzqF9mqqTrPtKPn2kTEYdFpBl6g4xphorSuVBtIrbSSMLsj.zDEcowG4B8Y 5IwikrB1_sb1UXlXfF68hPoLiSKpbtFIZiVMmXm0tJcszf8vP8wv0xSSbBw4 CS.xZUwWhXjAXXqJ_DLqIsUTSaACk84iBjaf0UVgyR_tnj6no0gviK4JtHkr QOj.x7j8Uro2MWgHq.0Ef7CNtPrkOLPVguSaooE5EwPL8AclzWS7K_Y5u.YO .gfYRkOwl6nt_6IQVbdIuMGokzTzN.Y2ueL52mzqqIdDbXiyWao_iRH0T X-Yahoo-SMTP: NQQt3c2swBAKSrExoA1eZuT7_w-- X-Rocket-Received: from [10.234.188.143] (n20087@192.88.212.49 with ) by smtp202.mail.bf1.yahoo.com with SMTP; 21 Oct 2013 05:15:05 -0700 PDT Subject: Re: Mag timing io360 References: <712BED03-4BEC-4018-8F2C-D2C0A9C72142@yahoo.com> From: Tom Content-Type: multipart/alternative; boundary=Apple-Mail-F445ADFE-C0F5-4FF1-B954-5F1CD10829F0 X-Mailer: iPad Mail (11A465) In-Reply-To: <712BED03-4BEC-4018-8F2C-D2C0A9C72142@yahoo.com> X-Original-Message-Id: <2979E080-D2E2-4E8D-8285-832135A073F6@yahoo.com> X-Original-Date: Mon, 21 Oct 2013 08:14:57 -0400 X-Original-To: Lancair Mailing List Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) --Apple-Mail-F445ADFE-C0F5-4FF1-B954-5F1CD10829F0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable >=20 >> Folks, >=20 > I am considering adjusting my mag timing in order to lower my chts. My en= gine is an io360 exp with a name plate stamped at 25 degrees. My eci flywhe= el is only marked at TC and 25 degrees but I figure each tooth is worth 2.5 d= egrees. The slick mags are 4373 and 4370 both marked at 25 degrees lag >=20 > There was a lycoming service instruction back in the mid 70s si1325a that a= dvocated backing timing off to 20 degrees to improve CHTs. =20 >=20 > I have three questions for the group.=20 >=20 > 1. Anybody running 20 degrees advance after changing from 25 degrees? Wort= h the effort on CHT? > 2. Anybody running 20 degrees on this engine type and chts running in the 3= 80 max range? > 3. If I move my timing down to 22 or so and leave the magneto lag on the i= mpulse magneto alone would there be any adverse effects other than lower pow= er and maybe a little more difficulty starting? >=20 > The si stated that the lag should be adjusted to 15 degrees for better sta= rts >=20 > Thanks in advance=20 >=20 > Tom >=20 > Lnc2 285 hrs >=20 > Service Instruction No. 1325A=20 > (Supersedes Service Instruction No. 1325)=20 > Engineering Aspects are=20 > FAA (DEER) Approved=20 > DATE: May 14, 1976=20 > SUBJECT:=20 > MODELS AFFECTED:=20 > TIME OF COMPLIANCE:=20 > Timing Change for IO-360 Series Engines=20 > IO-360-A series (not -A1B6D), -C, -D series, HIO-360-C1A, -C1B, AEIO-=20 > 360-A1B6 with serial numbers prior to 14435-51; IO-360-C1D6 with=20 > serial numbers prior to 14445-51, LIO-360-C1E6 with serial numbers=20 > prior to 1063-67 and AIO-360-A1A, -A1B, -B1B with serial numbers prior=20 > to 219-63; TIO-360-A1B with serial numbers prior to 145-64. See=20 > Service Bulletin No. 380 for IO-360-C1C and -C1F models.=20 > At overhaul or at owner's discretion.=20 > Certain advantages in engine operation have=20 > been found by changing engine timing from 25=C2=B0=20 > BTC to 20 BTC and reducing the lag angle to=20 > 15=C2=B0 on impulse coupling magnetos and 15=20 > retard angle on retard breaker magnetos whi-chever=20 > is applicable. Significant improve-ments=20 > in engine operating characteristics are=20 > achieved in above listed aircraft engine=20 > installations particularly in the areas of=20 > normal operation and cold weather starting.=20 > During cruise operation, cooler cylinder head=20 > temperatures can be expected resulting in=20 > improved service life of intake and exhaust=20 > valves. During full throttle operation the=20 > new spark setting will reduce possibility of=20 > detonation during extreme cold weather opera-tion.=20 > Consequently this modification has been=20 > incorporated in the production of new engines=20 > and may be incorporated in engines in service=20 > as follows:=20 > 1. Remove the left magneto and determine if=20 > it has an impulse coupling or if it is a=20 > retard breaker magneto; if it is a retard=20 > breaker magneto it cannot be converted to=20 > the 15 retard angle. However, a Bendix=20 > blue magneto which incorporates a 15 re-tard=20 > angle is available through Avco Ly-coming=20 > distributors. See "Parts Data" be-low.=20 > Install the replacement magneto as=20 > described in step 3.=20 > 2. If the left magneto has an impulse=20 > coupling, replace the coupling with a new=20 > one, LW-391429 on all models except reverse=20 > rotation engines; on these use impulse=20 > coupling LW-391427.=20 > 3. Install the magneto on the engine and=20 > retime both magnetos using the 20 timing=20 > mark on the starter ring gear instead of=20 > the 25 mark. See Avco Lycoming Operator's=20 > Manual 60297-12 for ignition timing proce-dure.=20 > 4. Replace the engine nameplate with a new=20 > one, Avco Lycoming P/N 61548 which indi-cates=20 > new timing angle. Also restamp the=20 > magneto nameplate to indicate the magneto=20 > is -9, -10 or -55 instead of -3, -6 or -45.=20 > PARTS DATA:=20 > 15 Lag Angle=20 > Magneto=20 > LW-349365-9=20 > LW-349365-10=20 > LW-51360-55=20 > Replaces=20 > Magneto=20 > LW-349365-3=20 > Magneto=20 > Model Engine Application=20 > S4LN-1227 IO-360-A1B,-A1B6,-C1C,-C1F,-C1D 6, -C1E6, AIO-360-A1A,=20 > -A1B, -B1B, AEIO-360-A1B6=20 > LW-349365-6 S4RN-1227 LIO-360-C1E6=20 > LW-51360-45 S4LN-21 IO-360-A1D >=20 > PARTS DATA (CONT.):=20 > 15=C2=B0 Retard Angle=20 > Magneto=20 > LW-349285-7=20 > LW-349285-8=20 > LW-163005-11=20 > LW-163005-12=20 > Replaces=20 > Magneto=20 > LW-349285-1=20 > LW-163005-2=20 > Magneto=20 > Model=20 > S4LN-1208=20 > S4RN-1208=20 > S4LN-200=20 > S4RN-200=20 > Engine Application=20 > IO-360-A1C, -C1C, -D1A; HIO-360-C1B; AIO-360-=20 > A1A; TIO-360-A1B=20 > LHIO-360 C1B=20 > IO-360-AlA, -A2A, -C1A; HIO-360-ClA; AEIO-360-=20 > A1A=20 > LHIO-360-C1A=20 > LW-391429=20 > LW-391427=20 > 61548=20 > 18484, 18485 -=20 > Impulse coupling, 15=C2=B0 lag angle (replaces LW-349359)=20 > Impulse coupling, 15 lag angle (replaces LW-349358 for magnetos on reverse= ro-tation=20 > engines)=20 > Engine nameplate (replaces nameplate with 25=C2=B0 BTC timing specified). S= ee Ser-vice=20 > Instruction No. 1304 for procurement procedure.=20 > These numbers for Avco Lycoming reference only. >=20 >=20 >=20 --Apple-Mail-F445ADFE-C0F5-4FF1-B954-5F1CD10829F0 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable



Folks,

I am considering adjusting my mag ti= ming in order to lower my chts.  My engine is an io360 exp with a name p= late stamped at 25 degrees.  My eci flywheel is only marked at TC and 2= 5 degrees but I figure each tooth is worth 2.5 degrees.  The slick mags= are 4373 and 4370 both marked at 25 degrees lag

There was a lycoming service instruction back in the mid 70s si1325a t= hat advocated backing timing off to 20 degrees to improve CHTs.  
=

I have three questions for the group. 

1. Anybody running 20 degrees advance after cha= nging from 25 degrees? Worth the effort on CHT?
2. Anybody running 20 degrees on this engine type an= d chts running in the 380 max range?
3. If I move my timing down to 22 or so and leave the magneto l= ag on the impulse magneto alone would there be any adverse effects other tha= n lower power and maybe a little more difficulty starting?

The si stated that the lag should be adjusted to 15 degrees f= or better starts

Thanks in advance 

Tom

Lnc2 285= hrs

Service Instruction No. 13= 25A 
(Supersedes Service Instruction No. 1325) 
Engineering A= spects are 
FAA (DEER) Approved 
DATE: May 14, 1976 SUBJECT: 
MODELS AFFECTED: 
TIME OF COMPLIANCE: 
Ti= ming Change for IO-360 Series Engines 
IO-360-A series (not -A1B6D),= -C, -D series, HIO-360-C1A, -C1B, AEIO- 
360-A1B6 with serial numbe= rs prior to 14435-51; IO-360-C1D6 with 
serial numbers prior to 1444= 5-51, LIO-360-C1E6 with serial numbers 
prior to 1063-67 and AIO-360= -A1A, -A1B, -B1B with serial numbers prior 
to 219-63; TIO-360-A1B w= ith serial numbers prior to 145-64. See 
Service Bulletin No. 380 fo= r IO-360-C1C and -C1F models. 
At overhaul or at owner's discretion.=  
Certain advantages in engine operation have 
been found by= changing engine timing from 25=C2=B0 
BTC to 20 BTC and reducing th= e lag angle to 
15=C2=B0 on impulse coupling magnetos and 15 retard angle on retard breaker magnetos whi-chever 
is applicable.= Significant improve-ments 
in engine operating characteristics are&= nbsp;
achieved in above listed aircraft engine 
installations par= ticularly in the areas of 
normal operation and cold weather startin= g. 
During cruise operation, cooler cylinder head 
temperatu= res can be expected resulting in 
improved service life of intake an= d exhaust 
valves. During full throttle operation the 
new s= park setting will reduce possibility of 
detonation during extreme c= old weather opera-tion. 
Consequently this modification has been&nbs= p;
incorporated in the production of new engines 
and may be inco= rporated in engines in service 
as follows: 
1. Remove the l= eft magneto and determine if 
it has an impulse coupling or if it is= a 
retard breaker magneto; if it is a retard 
breaker magne= to it cannot be converted to 
the 15 retard angle. However, a Bendix=  
blue magneto which incorporates a 15 re-tard 
angle is ava= ilable through Avco Ly-coming 
distributors. See "Parts Data" be-low= . 
Install the replacement magneto as 
described in step 3.&= nbsp;
2. If the left magneto has an impulse 
coupling, replace th= e coupling with a new 
one, LW-391429 on all models except reverse&n= bsp;
rotation engines; on these use impulse 
coupling LW-391427.&= nbsp;
3. Install the magneto on the engine and 
retime both magne= tos using the 20 timing 
mark on the starter ring gear instead of&nb= sp;
the 25 mark. See Avco Lycoming Operator's 
Manual 60297-12 fo= r ignition timing proce-dure. 
4. Replace the engine nameplate with a= new 
one, Avco Lycoming P/N 61548 which indi-cates 
new tim= ing angle. Also restamp the 
magneto nameplate to indicate the magne= to 
is -9, -10 or -55 instead of -3, -6 or -45. 
PARTS DATA:=  
15 Lag Angle 
Magneto 
LW-349365-9 
LW-349= 365-10 
LW-51360-55 
Replaces 
Magneto 
LW-3= 49365-3 
Magneto 
Model Engine Application 
S4LN-122= 7 IO-360-A1B,-A1B6,-C1C,-C1F,-C1D 6, -C1E6, AIO-360-A1A, 
-A1B, -B1B= , AEIO-360-A1B6 
LW-349365-6 S4RN-1227 LIO-360-C1E6 
LW-5136= 0-45 S4LN-21 IO-360-A1D


PARTS DATA (CONT.): 
15=C2=B0 R= etard Angle 
Magneto 
LW-349285-7 
LW-349285-8 =
LW-163005-11 
LW-163005-12 
Replaces 
Magneto&nb= sp;
LW-349285-1 
LW-163005-2 
Magneto 
Model = ;
S4LN-1208 
S4RN-1208 
S4LN-200 
S4RN-200 <= br>Engine Application 
IO-360-A1C, -C1C, -D1A; HIO-360-C1B; AIO-360-=  
A1A; TIO-360-A1B 
LHIO-360 C1B 
IO-360-AlA, -A2A, -= C1A; HIO-360-ClA; AEIO-360- 
A1A 
LHIO-360-C1A 
LW-3= 91429 
LW-391427 
61548 
18484, 18485 - 
Imp= ulse coupling, 15=C2=B0 lag angle (replaces LW-349359) 
Impulse coup= ling, 15 lag angle (replaces LW-349358 for magnetos on reverse ro-tation&nbs= p;
engines) 
Engine nameplate (replaces nameplate with 25=C2=B0 B= TC timing specified). See Ser-vice 
Instruction No. 1304 for procure= ment procedure. 
These numbers for Avco Lycoming reference only.




= --Apple-Mail-F445ADFE-C0F5-4FF1-B954-5F1CD10829F0--