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		jeffrey-j-paris(at)excite Guest
 
 
 
 
 
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				 Posted: Sun Jun 05, 2011 3:51 pm    Post subject: CHT issues on a 3300 | 
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				Dear Gurus of the Jabiru Engine World,
    
   I am currently back in flight test mode after finishing the "B" mods to my Zenith CH601XL. Before the Mods I was having CHT issues with the engine after I had installed the recommended " economy carb tuning kit" from Jabiru USA when we attended their excellent engine seminar.  Since then I have been battling High CHT's on my #2, #3, #4, #5 cylinders.  #1 runs cool and #6 is in the 260 F range.
    
    I have attempted all sorts of methods in an attempt to improve the cooling of my heads.  (See attached pictures)  During my second to last flight I removed all of my "enhancements" and just went back to factory FWF.  Here are the known Facts of my engine:
    
   A)  All CHT senders are placed between the plug and a washer (per Pete Krotje of Jab USA)
    
   B) I added a fiberglass cross flow to my rubber elbow to "smooth" out the air in my induction system into the carb.
    
   C) Jettting in the Carb  Main Jet #255 Needle Jet #285 ( Per Ben Krotje Jab USA)
    
   D)  My Flight Today in stabilized cruise of 2300 RPM to get my lowest CHT #'s:
    
   Cylinder #        EGT         CHT
    
   1                        1320        256
   2                        1302        313
   3                        1306        335
   4                        1343        324
   5                        1212        296
   6                        1308        251
    
   E) Oil temp 198 degrees F
   F) Pulled plugs burning a nice tan color, exhaust soot is a nice grayish tan as well.
   G)  Engine starts on first throw of the starter key, but I have to get throttle up or she stalls with the choke-on ( result of Economy tuning mods)
   H)m  Warm engine start is a no brainer.
    
     Any RPMs past 2300 up to 3000 results in cylinders 2, 3,4, 5  approaching and hitting 350 degress F.  I pull back on the throttle and aim my nose down to get things at least into the "yellow zone" of my AuRacle Engine Monitor indications.  I have tried all sorts of baffling, extending the lip on my cowls exit for airflow,  played with the jetting and induction system of my carb, and listened to all the suggestion  threads on the internet and still haven't got things under control.
    
   Any ideas or insights, pictures would be of great help.  Thanks for your time and consideration.
    
   Cheers,
    
   Jeff Paris   Jab 3300 Zenith Ch601XLB  and Jab 3300 Europa Monowheel Classic   Rochester, NY KSDC
 
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		aerobiz1(at)gmail.com Guest
 
 
 
 
 
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				 Posted: Sun Jun 05, 2011 7:13 pm    Post subject: CHT issues on a 3300 | 
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				Hi Jeff,
 
 This is what has worked for me.......
 1. Measure your actual Main Jet orifice with a metric drill or guage. I found the stamped size (#255 was actually #250, so I took it out to #260 - so from 2.5mm to 2.6mm)
  
 
 2. Removed the plenum chamber airfoil-shaped flow divider and placed a 1/2 inch diam tube/rod in its place.
 3. Drilled the main airbleed out to 3/16 inch _ that's the one that goes from the intake bellmouth straight to the needle jet emulsion tube.  Remove these, drill airbleed carefully and remove swarf, then before replacing the separate emulsion tube with its 4 x 2.5 mm holes, drill these 4 holes out to 3mm.
  
 
 While you are about it, you can drill out the choke system fuel bleed jet in the float bowl to 1 - 1.2 mm, and the idle airbleed jet in the bellmouth to 1.2 mm and use #35 pilot jet.
  FWIW,
 Martin
 J230
 
 On Mon, Jun 6, 2011 at 9:47 AM, Jeffrey J Paris <jeffrey-j-paris(at)excite.com (jeffrey-j-paris(at)excite.com)> wrote:
  [quote]  
   Dear Gurus of the Jabiru Engine World,
    
   I am currently back in flight test mode after finishing the "B" mods to my Zenith CH601XL. Before the Mods I was having CHT issues with the engine after I had installed the recommended " economy carb tuning kit" from Jabiru USA when we attended their excellent engine seminar.  Since then I have been battling High CHT's on my #2, #3, #4, #5 cylinders.  #1 runs cool and #6 is in the 260 F range.
     
    I have attempted all sorts of methods in an attempt to improve the cooling of my heads.  (See attached pictures)  During my second to last flight I removed all of my "enhancements" and just went back to factory FWF.  Here are the known Facts of my engine:
     
   A)  All CHT senders are placed between the plug and a washer (per Pete Krotje of Jab USA)
    
   B) I added a fiberglass cross flow to my rubber elbow to "smooth" out the air in my induction system into the carb.
    
   C) Jettting in the Carb  Main Jet #255 Needle Jet #285 ( Per Ben Krotje Jab USA)
    
   D)  My Flight Today in stabilized cruise of 2300 RPM to get my lowest CHT #'s:
    
   Cylinder #        EGT         CHT
    
   1                        1320        256
   2                        1302        313
   3                        1306        335
   4                        1343        324
   5                        1212        296
   6                        1308        251
    
   E) Oil temp 198 degrees F
   F) Pulled plugs burning a nice tan color, exhaust soot is a nice grayish tan as well.
   G)  Engine starts on first throw of the starter key, but I have to get throttle up or she stalls with the choke-on ( result of Economy tuning mods)
   H)m  Warm engine start is a no brainer.
    
     Any RPMs past 2300 up to 3000 results in cylinders 2, 3,4, 5  approaching and hitting 350 degress F.  I pull back on the throttle and aim my nose down to get things at least into the "yellow zone" of my AuRacle Engine Monitor indications.  I have tried all sorts of baffling, extending the lip on my cowls exit for airflow,  played with the jetting and induction system of my carb, and listened to all the suggestion  threads on the internet and still haven't got things under control.
     
   Any ideas or insights, pictures would be of great help.  Thanks for your time and consideration.
    
   Cheers,
    
   Jeff Paris   Jab 3300 Zenith Ch601XLB  and Jab 3300 Europa Monowheel Classic   Rochester, NY KSDC
    
    
 [b]
 
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		Clive J
 
 
  Joined: 03 Nov 2007 Posts: 340 Location: UK
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				 Posted: Mon Jun 06, 2011 12:31 am    Post subject: CHT issues on a 3300 | 
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				Hi Jeff, those look to be the narrrow air ducts with plugs  caps outside. There is a bigger set if your cowls will take  them?
  Regarding the inlet holes I know there is a school of thought  that with the shape you have the air can struggle to go in and would rather go  over the top of the cowl.
  Try a 'brow' to the holes, tape a strip of card or something  over the top coming forward to see if you aren't capturing the air  flow.
  What's going on at the back cylinder? Is there a space for the  air to escape without doing anything? My early 2200 ducts had a hole at the back  you could put your hand up (see sketch).
  The air will always take the easy way out. You do have the  blanks in between the barrels to stop the air getting out that way? I can see a  way out at the front on the front cylinder, close those gaps  also.
   
  Aside from that......
   
  Good luck, regards, Clive
   
   
 
    From:  owner-jabiruengine-list-server(at)matronics.com  [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of  Jeffrey J Paris
 Sent: 06 June 2011 00:47
 To:  jabiruengines(at)yahoogroups.com;  jabiruengine-list(at)matronics.com
 Subject: CHT issues  on a 3300
  
   
  Dear Gurus of the Jabiru Engine World,
   
  I am currently back in flight test mode after finishing the "B" mods to my  Zenith CH601XL. Before the Mods I was having CHT issues with the engine after I  had installed the recommended " economy carb tuning kit" from Jabiru USA when we  attended their excellent engine seminar.  Since then I have been battling  High CHT's on my #2, #3, #4, #5 cylinders.  #1 runs cool and #6 is in the  260 F range.
   
   I have attempted all sorts of methods in an attempt to improve the  cooling of my heads.  (See attached pictures)  During my second to  last flight I removed all of my "enhancements" and just went back to factory  FWF.  Here are the known Facts of my engine:
   
  A)  All CHT senders are placed between the plug and a washer (per Pete  Krotje of Jab USA)
   
  B) I added a fiberglass cross flow to my rubber elbow to "smooth" out the  air in my induction system into the carb.
   
  C) Jettting in the Carb  Main Jet #255 Needle Jet #285 ( Per Ben  Krotje Jab USA)
   
  D)  My Flight Today in stabilized cruise of 2300 RPM to get my lowest  CHT #'s:
   
  Cylinder #        EGT          CHT
   
  1                         1320        256
  2                         1302        313
  3                         1306        335
  4                         1343        324
  5                         1212        296
  6                         1308        251
   
  E) Oil temp 198 degrees F
  F) Pulled plugs burning a nice tan color, exhaust soot is a nice grayish  tan as well.
  G)  Engine starts on first throw of the starter key, but I have to get  throttle up or she stalls with the choke-on ( result of Economy tuning  mods)
  H)m  Warm engine start is a no brainer.
   
    Any RPMs past 2300 up to 3000 results in cylinders 2, 3,4, 5   approaching and hitting 350 degress F.  I pull back on the throttle  and aim my nose down to get things at least into the "yellow zone" of my AuRacle  Engine Monitor indications.  I have tried all sorts of baffling, extending  the lip on my cowls exit for airflow,  played with the jetting and  induction system of my carb, and listened to all the suggestion  threads on  the internet and still haven't got things under control.
   
  Any ideas or insights, pictures would be of great help.  Thanks for  your time and consideration.
   
  Cheers,
   
  Jeff Paris   Jab 3300 Zenith Ch601XLB  and Jab 3300 Europa  Monowheel Classic   Rochester, NY KSDC
 
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		wb2ssj(at)frontiernet.net Guest
 
 
 
 
 
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				 Posted: Mon Jun 06, 2011 2:48 am    Post subject: CHT issues on a 3300 | 
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				Jeff, call me tonight.   Tex   223-3220
   
   
   
  [quote]   ---
 
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		info(at)flylightning.net Guest
 
 
 
 
 
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				 Posted: Mon Jun 06, 2011 12:33 pm    Post subject: CHT issues on a 3300 | 
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				Jeff,  
    
 One thing missing is the dam in the front of the air-duct. This starts in the bottom of the duct and runs up to about the welsh plug in the head above the rocker shaft, may be about 2” tall.   
 If both ducts are like this in the front the majority of your cooling air is going underneath the front cylinder. This will also contribute to a lower pressure differential between the cowl and the duct, limiting the amount of air passing the cylinders.  
 I can provide a picture or two if you like.  
    
 Nick Otterback  
 Arion Aircraft  
    
 --
 
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		info(at)flylightning.net Guest
 
 
 
 
 
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				 Posted: Mon Jun 06, 2011 12:39 pm    Post subject: CHT issues on a 3300 | 
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				Jeff,  
    
 Along with my last email here is a picture. These are a new set of ducts, however it is important to put this air-dam in the front of the older ones as well.   
 Note in the right side of the picture is a cut out in the fins and a small half moon shape plug visible. That plug is for an oil galley, I would suggest making that dam this tall.  
    
 Thanks  
    
 Nick Otterback  
 Arion Aircraft  
    
 --
 
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		jeffrey-j-paris(at)excite Guest
 
 
 
 
 
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				 Posted: Tue Jun 07, 2011 12:48 pm    Post subject: CHT issues on a 3300 | 
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				Dear Jabiru 3300 Guru's,
    
   First of all thank you for all of your input I appreciate as I battle the heat demons in my cowl.  Yesterday I spent the day working on my CHT cooling issues.  I have attached some pictures for everyone to look at.  Anyways in addition to adding some aluminum sheet which profiles and seals in inboard baffles to the  cylinders I attempted to add airdams to the front of the baffles, per Nick Otterback's suggestion.  In addition, I added some rubber stuffing to seal up the back of baffles and I added rubber washers over each sparkplug to seal up and air leaks from the plugs as they protrude through the old style baffles.  
    
   First flight today yielded these numbers in cruise:
    
    RPM 2500-Note had to use to keep CHTs in at least the yellow range. All powered climbs yielded high temps approachin 350F. air temp at time of flight was 75 F  and oil temp was 212F.
    
   Cylinder      EGT (F)       CHT (F)
   1                   1315            265
   2                   1271            330
   3                   1311            315
   4                   1353            315
   5                   1219            326
   6                   1338            292
  
    
   RPM 2400-Note had to use to keep CHTs in at least the yellow range. All powered climbs yielded high temps approachin 350F.  In addition, I changed these items I removed the rubber from the back of the baffles, removed the butterfly baffles from underneath the cylinders, and added improved airdams to the fron of the 2,4,6 cylinder bank.  Outside temp at flight was 88 F  Oil Temp.  212F
    
   Cylinder      EGT (F)       CHT (F)
   1                   1285            256
   2                   1258            316
   3                   1282            318
   4                   1347            315
   5                   1204            271
    
   In a sense I have made some progress.  However,  I cannot do a normal rate of climb without cylinders 2,3,4,5 heading for the races towards 350F  and I can't even imagine what temps I would see at max gross weight with a passenger.  So I am obviously not getting the utility out of the aircraft as I would like.  
    
   Thanks for your time and consideration.  I just want to go out flying like the old days before I messed things up!  LOL
    
   Cheers Jeff Paris  2 Jabs in the nest/both sick
    
    
    
   2514.jpg   Shows a "scoop" that I added to aid in my old style oil cooler Seems to work temps on cooler days 190F  hot days 212F.
    
   2515.jpg   Top of engine looking forward.
    
   2529.jpg   I added some aluminum sheet, cut precisely to the cylinder profile to seal up both inside baffles.
    
    2530.jpg  Per Nick Otterback's / Flylightning suggestion I added an air dam to the front right baffle on the 2,4,6 cylinder bank
    
   2531.jpg  Shows the 1,3,5 cylinder baffle entrance
    
   2532.jpg   I experimented with adding the butterfly cylinder baffles to the underside of the cylinders, I tested them during my first flight today and                    removed them for the second flight
 
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		aerobiz1(at)gmail.com Guest
 
 
 
 
 
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				 Posted: Tue Jun 07, 2011 1:39 pm    Post subject: CHT issues on a 3300 | 
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				Jeff,
 
 I reckon the angle that your oil cooler is presenting to the incoming air is too great.  A normal tube and fin radiator like that does NOT like any more than 20 degrees before the air 'bounces' off.  Less than 7 degrees is ideal.
  
 
 Remind me, what instrumentation are you using to gain these numbers ?
 We have had issues with a Dynon reading high....
 Martin
 
  On Wed, Jun 8, 2011 at 6:44 AM, Jeffrey J Paris <jeffrey-j-paris(at)excite.com (jeffrey-j-paris(at)excite.com)> wrote:
 [quote]  Dear Jabiru 3300 Guru's,
    
   First of all thank you for all of your input I appreciate as I battle the heat demons in my cowl.  Yesterday I spent the day working on my CHT cooling issues.  I have attached some pictures for everyone to look at.  Anyways in addition to adding some aluminum sheet which profiles and seals in inboard baffles to the  cylinders I attempted to add airdams to the front of the baffles, per Nick Otterback's suggestion.  In addition, I added some rubber stuffing to seal up the back of baffles and I added rubber washers over each sparkplug to seal up and air leaks from the plugs as they protrude through the old style baffles.  
     
   First flight today yielded these numbers in cruise:
    
    RPM 2500-Note had to use to keep CHTs in at least the yellow range. All powered climbs yielded high temps approachin 350F. air temp at time of flight was 75 F  and oil temp was 212F.
    
   Cylinder      EGT (F)       CHT (F)
   1                   1315            265
   2                   1271            330
   3                   1311            315
   4                   1353            315
   5                   1219            326
   6                   1338            292
  
    
   RPM 2400-Note had to use to keep CHTs in at least the yellow range. All powered climbs yielded high temps approachin 350F.  In addition, I changed these items I removed the rubber from the back of the baffles, removed the butterfly baffles from underneath the cylinders, and added improved airdams to the fron of the 2,4,6 cylinder bank.  Outside temp at flight was 88 F  Oil Temp.  212F
     
   Cylinder      EGT (F)       CHT (F)
   1                   1285            256
   2                   1258            316
   3                   1282            318
   4                   1347            315
   5                   1204            271
    
   In a sense I have made some progress.  However,  I cannot do a normal rate of climb without cylinders 2,3,4,5 heading for the races towards 350F  and I can't even imagine what temps I would see at max gross weight with a passenger.  So I am obviously not getting the utility out of the aircraft as I would like.  
     
   Thanks for your time and consideration.  I just want to go out flying like the old days before I messed things up!  LOL
    
   Cheers Jeff Paris  2 Jabs in the nest/both sick
    
    
    
   2514.jpg   Shows a "scoop" that I added to aid in my old style oil cooler Seems to work temps on cooler days 190F  hot days 212F.
    
   2515.jpg   Top of engine looking forward.
    
   2529.jpg   I added some aluminum sheet, cut precisely to the cylinder profile to seal up both inside baffles.
    
    2530.jpg  Per Nick Otterback's / Flylightning suggestion I added an air dam to the front right baffle on the 2,4,6 cylinder bank
    
   2531.jpg  Shows the 1,3,5 cylinder baffle entrance
    
   2532.jpg   I experimented with adding the butterfly cylinder baffles to the underside of the cylinders, I tested them during my first flight today and                    removed them for the second flight
  [b]
 
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		jerryvmd
 
 
  Joined: 18 Apr 2008 Posts: 25
 
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				 Posted: Wed Jun 08, 2011 10:04 am    Post subject: CHT issues on a 3300 | 
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				Jeff,
 I had similar issues early on.  Check the archives as there is alot of 
 info on cooling issues.  Two things that worked for me. 1.  It appears 
 that your air dams at the entrance to the Ram Ducts my be too low.  2. 
 Remove some of the cowl on the bottom half at the air exit around the 
 nose wheel strut.  Then temporarily duct tape a piece of aluminum to 
 make the rim bevel larger.  This causes a negative air pressure actually 
 drawing more air out the bottom.  In effect creating more air moving 
 from the inlets through the cowl/cylinders to the exit.  The size of the 
 exit hole is important but the larger lip helped alot.  I now have the 
 opposite problem.  In the winter my cylinder head temps tend to run cold 
 (several read only 220 to 250) with a Grand Rapids EIS.  In summer 
 (Pennsylvania) in a long climb number 3 cylinder might get to 350 but 
 returns to upper 200's after lowering nose to cruise.
 Jerry
 On 6/7/2011 4:44 PM, Jeffrey J Paris wrote:
  	  | Quote: | 	 		   Dear Jabiru 3300 Guru's,
  First of all thank you for all of your input I appreciate as I battle 
  the heat demons in my cowl.  Yesterday I spent the day working on my 
  CHT cooling issues.
 
 
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		dons701
 
 
  Joined: 22 May 2009 Posts: 80 Location: Hershey, PA
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				 Posted: Wed Jun 08, 2011 10:26 am    Post subject: Re: CHT issues on a 3300 | 
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				Exactly what I had to do with my CH701  Jerry. Cut the exit much larger and bought some white aluminum flashing to make a 4 inch lip to start with. My temps took a dive.  My inlets are about 3 to 4 times the size of Jeff's much faster plane......Don B
 
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 _________________ Zenith 701 #76120
 
Jabiru 2200A #2456  95 hours
 
Sensenich Wood 64-PJ-36 Prop | 
			 
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		Clive J
 
 
  Joined: 03 Nov 2007 Posts: 340 Location: UK
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				 Posted: Wed Jun 08, 2011 12:11 pm    Post subject: CHT issues on a 3300 | 
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				When I had the Rotax cowl on my Esqual I got a step change in the
 cooling by adding an outlet baffle.
 It went back three times as far as it went down, so it was more
 streamlined than the 'lips' that I've seen added by others. I don't have
 a picture of mine but I do of the one I copied, Dave Mc was good enough
 to send me the attached.
 
 If you think about it, a hanging baffle on the cowl outlet will create
 some suction but not as much as something more streamlined. I cured my
 head cooling with the duct like this but went on to change to a new cowl
 for oil cooling reasons.
 I would recommend trying a more streamlined 'baffle/duct' on the outlet.
 
 Regarding the dam on the inlet, there is a school of thought that the
 tumbling effect of a vertical baffle is better than a 'ramp' I recall
 someone trying both and finding the vertical baffle better.
 
 The hanging baffles inside the ducts that restrict airflow, restrict
 airflow so there is a balance between how much they restrict and how
 much they deflect, any restriction is not a good thing with marginal
 cooling.
 
 Roger mentioned the smoke test's to see where the airflow goes, this
 will show mow much air gets deflected over the cowl and so bypasses the
 ram air entry. Another reason why creating more 'pull' on the outlet is
 so successful.....IMHO.
 
 Regards, Clive
  
 
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