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High compression, high CHTs

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jrstone(at)insightbb.com
Guest

Posted: Sun Sep 23, 2007 3:47 am Post subject: High compression, high CHTs

First let me announce the fact that N918JK is  flying, as of about a week ago.  

 Second, I need some advice to clear up high  CHTs.

 I am running ElectroAir's ignition on lower plugs  and a Slick Mag on the upper plugs.  I have 10-1 pistons in new  Lycoming jugs.  On the first few short flights my CHTs climbed right  through redline on 5 or 6 cylinders in less than 5 minutes.  My EIS  timing was factory set to 23 deg to account for the high compression and I set  the mag at 25 deg per the engine placard.  I reduced the EIS to 20 degrees  and saw some relief but two of the CHTs (6 and 2) still climbing into the low to  mid 400s.  Today I plan on retarding the Mag to 20 degrees because during  cruise I felt a vibration and turned the Mag off and the vibration went  away so I feel like the two ignitions were not working together.  CHT #4 is  my coolest with a difference from the hottest (#6) 80-100 deg.

 Question:  What timing have you high  compression guys been using to get reasonable CHTs?  

 Other than ensuring no leaks in the baffles what  else can I do?

 BTW, a friend installed the louvers on the bottom  of his F-1 cowl and it had no effect so I'm not going there until  last.

 Thanks for you time,

 Jim Stone

 Louisville KY

  [quote][b]

fairlea(at)amtelecom.net
Guest

Posted: Sun Sep 23, 2007 4:11 am Post subject: High compression, high CHTs

Jim  

            I have had ok service from the elctro air systems but others have noted erratic ignition timing .   Contact Jim Winings, in Indianapolis regarding his electro air situation, as it sounds similar to what you are experiencing.      

   

Tom Martin  

         

  

From: owner-rocket-list-server(at)matronics.com [mailto:owner-rocket-list-server(at)matronics.com] On Behalf Of Jim Stone

 Sent: September 23, 2007 7:47 AM

 To: rocket-list(at)matronics.com

 Subject: High compression, high CHTs  

  

     

First let me announce the fact that N918JK is flying, as of about a week ago.    

    

Second, I need some advice to clear up high CHTs.  

    

I am running ElectroAir's ignition on lower plugs and a Slick Mag on the upper plugs.  I have 10-1 pistons in new Lycoming jugs.  On the first few short flights my CHTs climbed right through redline on 5 or 6 cylinders in less than 5 minutes.  My EIS timing was factory set to 23 deg to account for the high compression and I set the mag at 25 deg per the engine placard.  I reduced the EIS to 20 degrees and saw some relief but two of the CHTs (6 and 2) still climbing into the low to mid 400s.  Today I plan on retarding the Mag to 20 degrees because during cruise I felt a vibration and turned the Mag off and the vibration went away so I feel like the two ignitions were not working together.  CHT #4 is my coolest with a difference from the hottest (#6) 80-100 deg.  

    

Question:  What timing have you high compression guys been using to get reasonable CHTs?    

    

Other than ensuring no leaks in the baffles what else can I do?  

    

BTW, a friend installed the louvers on the bottom of his F-1 cowl and it had no effect so I'm not going there until last.  

    

Thanks for you time,  

    

Jim Stone  

    

Louisville KY  

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n395v

Joined: 10 Jan 2006
Posts: 450

Posted: Sun Sep 23, 2007 5:48 am Post subject: Re: High compression, high CHTs

Congratulations on getting in the air.

I have a stock IO540 and fought CHTs forever, tweaked baffling mesed with timing. Got to where all was ok in cruise but always on climbout I quickly blew through 400Deg F everytime.



Finally put louvers in and have had no problems since.



I think your friend with the louvers probably has an additional issue.

_________________
Milt

Wolfgang

Joined: 17 Feb 2007
Posts: 7
Location: Cloudcroft, New Mexico

Posted: Sun Sep 23, 2007 7:23 am Post subject: High compression, high CHTs

Hi Jim,  

   

congratulations!!  

   

Calibrate your CHT probes. (Check on the ground what a calibrated high quality temp. tester (Fluke) will show you).  

If you are using bayonet type probes they might be reading higher and are considered fairly inaccurate (screw in type are more accurate)  

What EM are you using?   

If your ignition would be the only problem area you’d see high CHTs on all Cylinders.  

What is your T/O fuel flow?  

Check your baffle gaps! I am referring to Kent Pacers book “Speed with Economy” (P. 59) :  

   

… The cylinder barrel baffle gap was best at 7/8” to 1.0 inch. The cylinder head baffle gap was much more critical to controlling temperatures,   

but gave best results at dimensions of 21/4”.  

   

When I was using 10:1s  the engine was timed at 20deg. and I had no problems, however I used a Dual LSE Plasma III setup.  

Also check that the top part of your cowling intakes allows a smooth airflow transition towards your engine baffling. If this area is rough or curves up at steep angles your  

cooling airflow will be very disturbed.  

   

Hope this helped.  

   

   

Wolfgang   

   

   

              

         

  

From: owner-rocket-list-server(at)matronics.com [mailto:owner-rocket-list-server(at)matronics.com] On Behalf Of Jim Stone

 Sent: Sunday, September 23, 2007 5:47 AM

 To: rocket-list(at)matronics.com

 Subject: High compression, high CHTs  

  

     

First let me announce the fact that N918JK is flying, as of about a week ago.    

    

Second, I need some advice to clear up high CHTs.  

    

I am running ElectroAir's ignition on lower plugs and a Slick Mag on the upper plugs.  I have 10-1 pistons in new Lycoming jugs.  On the first few short flights my CHTs climbed right through redline on 5 or 6 cylinders in less than 5 minutes.  My EIS timing was factory set to 23 deg to account for the high compression and I set the mag at 25 deg per the engine placard.  I reduced the EIS to 20 degrees and saw some relief but two of the CHTs (6 and 2) still climbing into the low to mid 400s.  Today I plan on retarding the Mag to 20 degrees because during cruise I felt a vibration and turned the Mag off and the vibration went away so I feel like the two ignitions were not working together.  CHT #4 is my coolest with a difference from the hottest (#6) 80-100 deg.  

    

Question:  What timing have you high compression guys been using to get reasonable CHTs?    

    

Other than ensuring no leaks in the baffles what else can I do?  

    

BTW, a friend installed the louvers on the bottom of his F-1 cowl and it had no effect so I'm not going there until last.  

    

Thanks for you time,  

    

Jim Stone  

    

Louisville KY  

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       [quote][b]

CalBru(at)aol.com
Guest

Posted: Sun Sep 23, 2007 8:31 am Post subject: High compression, high CHTs

I'd like details re: the louvers.  I fly 116 very gingerly in the  summer, have a ball with it in the winter.  It has cold air induction,  tuned exhaust and a plenum, but still seem to run hot.

  

 Thanks,

  

 Cal

  

 116

  

 118 hours



See what's t="_blank">Make AOL Your Homepage.

  [quote][b]

Hr2pilot(at)aol.com
Guest

Posted: Sun Sep 23, 2007 8:38 am Post subject: High compression, high CHTs

What do you all consider high temps?

 john



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n395v

Joined: 10 Jan 2006
Posts: 450

Posted: Sun Sep 23, 2007 2:34 pm Post subject: Re: High compression, high CHTs

To me anything over 380 is too high.





[quote="What do you all consider high temps?

 john

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_________________
Milt

smokyray(at)yahoo.com
Guest

Posted: Mon Sep 24, 2007 3:36 am Post subject: High compression, high CHTs

Jim, 

  I have the exact same setup in my HR2, a LyCon IO-540 with 10:1's and a EI ignition. I have low CHT's comparatively, 330F in cruise on the lowest, 350F on the highest. Since you are still breaking it in, I would give a chance for the rings to seat, something highly evident inflight. You get a noticeable CHT and oil temp drop. You need to run it hard, I mean HARD the first 5 hours. I typically do a full power climb to 10,000+ feet on a new engine several times. The timing issue sounds like the Mag, but one easy way to check is to isolate them inflight which it sounds like you have. The EI timing is pretty straightforward and works good, lasts a long time. I would check the timing on both, clean the plugs and try it again...



Rob Ray



Tom Martin <fairlea(at)amtelecom.net> wrote:[quote]          v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);}  <![endif]-->     st1\:*{behavior:url(#default#ieooui) }  <![endif]-->       <![endif]-->       <![endif]-->     Jim

              I have had ok service from the elctro air systems but others have noted erratic ignition timing .   Contact Jim Winings, in Indianapolis regarding his electro air situation, as it sounds similar to what you are experiencing.    

   

  Tom Martin

   

        

  From: owner-rocket-list-server(at)matronics.com [mailto:owner-rocket-list-server(at)matronics.com] On Behalf Of Jim Stone

 Sent: September 23, 2007 7:47 AM

 To: rocket-list(at)matronics.com

 Subject: High compression, high CHTs

  

   

    First let me announce the fact that N918JK is flying, as of about a week ago.  

  

    Second, I need some advice to clear up high CHTs.

  

    I am running ElectroAir's ignition on lower plugs and a Slick Mag on the upper plugs.  I have 10-1 pistons in new Lycoming jugs.  On the first few short flights my CHTs climbed right through redline on 5 or 6 cylinders in less than 5 minutes.  My EIS timing was factory set to 23 deg to account for the high compression and I set the mag at 25 deg per the engine  placard.  I reduced the EIS to 20 degrees and saw some relief but two of the CHTs (6 and 2) still climbing into the low to mid 400s.  Today I plan on retarding the Mag to 20 degrees because during cruise I felt a vibration and turned the Mag off and the vibration went away so I feel like the two ignitions were not working together.  CHT #4 is my coolest with a difference from the hottest (#6) 80-100 deg.

  

    Question:  What timing have you high compression guys been using to get reasonable CHTs?  

  

    Other than ensuring no leaks in the baffles what else can I do?

  

    BTW, a friend installed the louvers on the bottom of his F-1 cowl and it had no effect so I'm not going there until last.

  

    Thanks for you time,

  

    Jim Stone

  

    Louisville KY

  

  [quote]  [b]

russ(at)wernerworld.com
Guest

Posted: Mon Sep 24, 2007 5:44 am Post subject: High compression, high CHTs

Jim,

  

 I run my mag at 25 degrees.  What kind of temp did you  see?  Lycoming redline is 500F.  Hope you dind't get that  high.

  

 Russ

  

  

 ---

jrstone(at)insightbb.com
Guest

Posted: Mon Sep 24, 2007 6:06 pm Post subject: High compression, high CHTs

Thanks Rob,

 What timing do have your mag and EI set  at?

 Jim

 [quote]   ---

jrstone(at)insightbb.com
Guest

Posted: Mon Sep 24, 2007 6:18 pm Post subject: High compression, high CHTs

Hey Russ,

 The second flight they were climbing to redline and  I had to land at my emergency field.  They have responded to retarding the  timing to 20 deg.  I also discovered the mag was not timed where I  had set it, it was way early, probably a rookie mistake.  I think I  may have seen the drop that comes with initial breakin just today, temps were  better (less than 410).  The engine does not seem to be as smooth as I  would like but I have little experience behind a souped up 540.  I will  keep moving the timing around until I find the setting that is best for my  engine.

 Jim Stone 

 Louisville

 [quote]   ---

Jones15183(at)aol.com
Guest

Posted: Mon Sep 24, 2007 7:10 pm Post subject: High compression, high CHTs

Jim. are you aware that your EIS has an automatic advance of +7  degrees.  So whatever you set the initial setting on , at 2500 RPM   degrees  the timing is supposed to read 25 degrees BTDC. Or  whatever your manufacturer calls for  your engine.   At 23/23 you  might be reading a timing of approx. 32 degrees BTDC.  At alt. your highest  timing might be 38 degrees BTDC.  There are a lot of questions that could  be answered about your Eis if I knew all the parameters.  Do You have the  CSTW or the rear timing mount system.  It makes a lots of defference in  adjusting your timing system.   billy  waters



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  [quote][b]

rocketbob(at)gmail.com
Guest

Posted: Mon Sep 24, 2007 7:54 pm Post subject: High compression, high CHTs

Jim, congrats on your first flight.  Its too bad you have to spend this time debugging and not enjoying something you spent years building.



1.  What type of pickup (crank trigger/mag hole trigger)?

2.  Which plugs are you running on the bottoms? 

3.  Have you connected a voltmeter to the the Electroair to determine how much advance there is?

4.  Why are your mags not timed exactly to the EI?



Regards,

Bob Japundza

RV-6 flying F1 under const.

 



On 9/23/07, Jim Stone <jrstone(at)insightbb.com (jrstone(at)insightbb.com)> wrote:[quote]        First let me announce the fact that N918JK is  flying, as of about a week ago.  

 Second, I need some advice to clear up high  CHTs.

 I am running ElectroAir's ignition on lower plugs  and a Slick Mag on the upper plugs.  I have 10-1 pistons in new  Lycoming jugs.  On the first few short flights my CHTs climbed right  through redline on 5 or 6 cylinders in less than 5 minutes.  My EIS  timing was factory set to 23 deg to account for the high compression and I set  the mag at 25 deg per the engine placard.  I reduced the EIS to 20 degrees  and saw some relief but two of the CHTs (6 and 2) still climbing into the low to  mid 400s.  Today I plan on retarding the Mag to 20 degrees because during  cruise I felt a vibration and turned the Mag off and the vibration went  away so I feel like the two ignitions were not working together.  CHT #4 is  my coolest with a difference from the hottest (#6) 80-100 deg.

 Question:  What timing have you high  compression guys been using to get reasonable CHTs?  

 Other than ensuring no leaks in the baffles what  else can I do?

 BTW, a friend installed the louvers on the bottom  of his F-1 cowl and it had no effect so I'm not going there until  last.

 Thanks for you time,

 Jim Stone

 Louisville KY

  [quote][b]  http://www.matronics.com/Navigator?Rocket-List http://forums.matronics.com  [quote][b]

jrstone(at)insightbb.com
Guest

Posted: Tue Sep 25, 2007 3:59 am Post subject: High compression, high CHTs

Billy,

 No I am not aware of an automatic advance of +7 degrees.

 I have had daily phone conversations with Mike (the new owner) of  ElectroAir.  He has been most helpful and very patient with troubleshooting  and adjusting the EIS.  He set the timing at 23 BTDC due to the 10-1  pistons.  My pistons are forged racing pistons from a very nice engine  overhaul shop in Ontario CA, sorry I forgot the name.  The pistons tops are  ceramic coated and have a MolyB coating on the sides, and they are in factory  new Lyc jugs.  This may explain the high temps.  

 The ElectroAir system uses a toothed ring on the crank behind the flywheel  and a magnetic sensor to read the gap.  This signal goes to a controller  aft of the firewall, which then controls the coils located forward of the  firewall.  A MAP  or manifold air pressure sensor is teed into the  cockpit MAP gage line to provide an input to the controller at all power setting  to optimize the ignition curve.  

 Please tell me what you recommend the timing be set at.  My engine is  a O-540 E4B5 with a Bendix fuel servo RSA5 and Airflow Performance spider  valve.  

 Don Rivera said the engine appears out of time after reviewing some takeoff  parameters like MAP, RPM, FF,CHT and EGTs and fuel pressure, which btw were all  within limits.

 Thanks for the help,

 Jim Stone

 Louisville KY

  

  

 [quote]   ---

jrstone(at)insightbb.com
Guest

Posted: Tue Sep 25, 2007 4:12 am Post subject: High compression, high CHTs

Hey Bob,

 Thanks, and you are right, it has been a real pain.  All my attention has been on the temps and trying to get the engine running  super smooth.  It took 5 flights before I was able to do a stall to  verify the stall speed for landing, I got to do 4 landings without knowing this  speed.  It was no big deal, I just flew the airplane.

 In answer to your questions,

 1. Crank

 2.REM 37BY, top and bottom per  ElectroAir

 3.Yes, ElectroAir said it is correct, although  after small adjustment I did not verify again.

 4. The mag is now timed to match the EIS but is not  required to be (I'm told by ElectroAir)

 Thanks for your interest and help,

 Jim Stone

 Louisville KY

  

 [quote]   ---

rocketbob(at)gmail.com
Guest

Posted: Tue Sep 25, 2007 5:06 am Post subject: High compression, high CHTs

Jim, what's the advance voltmeter showing at cruise power.  It should be right at 25 degrees in cruise, unless manifold pressure drops which it shouldn't unless you are at 8-9K and above.  Also, the old Electroairs were timed at 0 deg. BTDC, not sure if the new purple ones are still that way. 



Regards,

Bob Japundza

RV-6 flying F1 under const.



On 9/25/07, Jim Stone < jrstone(at)insightbb.com (jrstone(at)insightbb.com)> wrote:[quote]       Hey Bob,

 Thanks, and you are right, it has been a real pain.  All my attention has been on the temps and trying to get the engine running  super smooth.  It took 5 flights before I was able to do a stall to  verify the stall speed for landing, I got to do 4 landings without knowing this  speed.  It was no big deal, I just flew the airplane.

 In answer to your questions,

 1. Crank

 2.REM 37BY, top and bottom per  ElectroAir

 3.Yes, ElectroAir said it is correct, although  after small adjustment I did not verify again.

 4. The mag is now timed to match the EIS but is not  required to be (I'm told by ElectroAir)

 Thanks for your interest and help,

 Jim Stone

 Louisville KY

  

 [quote]   ---

smokyray(at)yahoo.com
Guest

Posted: Tue Sep 25, 2007 9:57 am Post subject: High compression, high CHTs

My mag is 25 btdc, the EI is an old one installed at TDC with a crank sensor. It has a selector switch in the cockpit to activate/deactivate the advance. I am running airboat Denso spark plugs with Accel plug wires. I ran the exact same setup in my RV4. Normal cruise advance at 20" MP is 34-36. I would give EI a call and see if they can help. One way to eliminate the problem would be to replace both the mag and the EI separately and make test runs. Good Luck...

   

  RR



Jim Stone <jrstone(at)insightbb.com> wrote:

  [quote]    Thanks Rob,

  What timing do have your mag and EI set at?

  Jim

  [quote]  ---

Jones15183(at)aol.com
Guest

Posted: Tue Sep 25, 2007 7:39 pm Post subject: High compression, high CHTs

Jim, there are so many questions that cannot be answered by email. My phone  no. is 254 853-2426. 

 If you want to call me that's ok.  I will be home after 7 pm Wed.  night.  billy



See whatarget="_blank">Make AOL Your Homepage.

  [quote][b]

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