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High CHT on #2 mystery

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mark.t.mueller(at)comcast
Guest

Posted: Sun Mar 18, 2012 4:31 am Post subject: High CHT on #2 mystery

Just picked 33R up from annual inspection yesterday, and when flying back to my home 'drome I could not keep my #2 CHT under 400 regardless of power setting, airspeed, or altitude.  At 3500' and 2600 RPM in level cruise with an OAT of 72F #2 hit 440!!!  This was NOT the case before annual except in extended climb.  That cylinder is now running a good 30 - 40 hotter than before annual.  The rest of the cylinders are running close to where they were before annual.  



Oil temp stayed below 190.

I asked my IA what had been done, and he said the only thing he had to do was adjust the timing on one mag by a couple degrees and replaced the gasket on that mag.  I have a LASAR ignition, and he allegedly used the T-300 tool I provided.

  



The SB388C test was done, and he stated was well within tolerance, and good comps on all cylinders.

Prior to annual, the #2 had a much higher EGT than the others, but normal CHT.  All four CHTs were within 20+- during normal cruise.  Now they are a good 40+ difference between #2 and coolest.  Front cyls have always run hotter than rear since my baffling was rebuilt during OH 4 years ago.

  



Now, the obvious answer is my timing is screwed up, but the motor is running more smoothly and stronger than ever (smoother than before annual) and I don't want to give that up.  In addition, in my experience owning 33R it is almost NEVER the "obvious" answer...

  



I still have to take a day off work and root around to see if there was any damage to the front baffling when they reassembled the cowling or other simple things (I am really hoping it's something simple).

  



Looking for ideas.  It is clearly a thermodynamics problem, but what might be the best way to approach this without sacrificing the best my motor has run in a while?

Is it possible that low batteries in the T-300 tool might have caused an error in adjusting timing?

  



What are common baffling issues that might contribute to such a dramatic change in #2 CHT without significantly effecting the other cylinders?

Is it possible one cylinder is hypersensitive to timing over all the others?  If so, what might this indicate that doesn't show up on an SB388C or other routine engine examination during annual?

  



Thanks in advance,

Mark T. Mueller

 

Tiger N1533R



 



  [quote][b]

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flyv35b(at)minetfiber.com
Guest

Posted: Sun Mar 18, 2012 5:19 am Post subject: High CHT on #2 mystery

On 3/18/2012 5:30 AM, Mark T. Mueller wrote:

 	  Quote: 	
		   Just picked 33R up from annual inspection yesterday, and when flying

 back to my home 'drome I could not keep my #2 CHT under 400 regardless

 of power setting, airspeed, or altitude.  At 3500' and 2600 RPM in level

 cruise with an OAT of 72F #2 hit 440!!!  This was NOT the case before

 annual except in extended climb.  That cylinder is now running a good 30

 - 40 hotter than before annual.  The rest of the cylinders are running

 close to where they were before annual.



 Oil temp stayed below 190.



 I asked my IA what had been done, and he said the only thing he had to

 do was adjust the timing on one mag by a couple degrees and replaced the

 gasket on that mag.  I have a LASAR ignition, and he allegedly used the

 T-300 tool I provided.



 The SB388C test was done, and he stated was well within tolerance, and

 good comps on all cylinders.



 Prior to annual, the #2 had a much higher EGT than the others, but

 normal CHT.  All four CHTs were within 20+- during normal cruise.  Now

 they are a good 40+ difference between #2 and coolest.  Front cyls have

 always run hotter than rear since my baffling was rebuilt during OH 4

 years ago.



 Now, the obvious answer is my timing is screwed up, but the motor is

 running more smoothly and stronger than ever (smoother than before

 annual) and I don't want to give that up.  In addition, in my experience

 owning 33R it is almost NEVER the "obvious" answer...



 I still have to take a day off work and root around to see if there was

 any damage to the front baffling when they reassembled the cowling or

 other simple things (I am really hoping it's something simple).



 Looking for ideas.  It is clearly a thermodynamics problem, but what

 might be the best way to approach this without sacrificing the best my

 motor has run in a while?



 Is it possible that low batteries in the T-300 tool might have caused an

 error in adjusting timing?



 What are common baffling issues that might contribute to such a dramatic

 change in #2 CHT without significantly effecting the other cylinders?



 Is it possible one cylinder is hypersensitive to timing over all the

 others?  If so, what might this indicate that doesn't show up on an

 SB388C or other routine engine examination during annual?



 Thanks in advance,



 Mark T. Mueller

 Tiger N1533R



Is your plane an AG-5B?  What kind/brand of CHT/EGT instrumentation?
	




Cliff

- The Matronics TeamGrumman-List Email Forum -

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teamgrumman(at)yahoo.com
Guest

Posted: Sun Mar 18, 2012 10:08 am Post subject: High CHT on #2 mystery

I would double check the timing.  If it seems smoother, it's likely the timing was bumped up enough to make a difference.  It's all a compromise.  EGT vs CHT. 

        From: Mark T. Mueller <mark.t.mueller(at)comcast.net>

 To: teamgrumman-list(at)matronics.com 

 Sent: Sunday, March 18, 2012 5:30 AM

 Subject:  High CHT on #2 mystery

 Just picked 33R up from annual inspection yesterday, and when flying back to my home 'drome I could not keep my #2 CHT under 400 regardless of power setting, airspeed, or altitude.  At 3500' and 2600 RPM in level cruise with an OAT of 72F #2 hit 440!!!  This was NOT the case before annual except in extended climb.  That cylinder is now running a good 30 - 40 hotter than before annual.  The rest of the cylinders are running close to where they were before annual.  

Oil temp stayed below 190.

I asked my IA what had been done, and he said the only thing he had to do was adjust the timing on one mag by a couple degrees and replaced the gasket on that mag.  I have a LASAR ignition, and he allegedly used the T-300 tool I provided.

The SB388C test was done, and he stated was well within tolerance, and good comps on all cylinders.

Prior to annual, the #2 had a much higher EGT than the others, but normal CHT.  All four CHTs were within 20+- during normal cruise.  Now they are a good 40+ difference between #2 and coolest.  Front cyls have always run hotter than rear since my baffling was rebuilt during OH 4 years ago.

Now, the obvious answer is my timing is screwed up, but the motor is running more smoothly and stronger than ever (smoother than before annual) and I don't want to give that up.  In addition, in my experience owning 33R it is almost NEVER the "obvious" answer...

I still have to take a day off work and root around to see if there was any damage to the front baffling when they reassembled the cowling or other simple things (I am really hoping it's something simple).

Looking for ideas.  It is clearly a thermodynamics problem, but what might be the best way to approach this without sacrificing the best my motor has run in a while?

Is it possible that low batteries in the T-300 tool might have caused an error in adjusting timing?

What are common baffling issues that might contribute to such a dramatic change in #2 CHT without significantly effecting the other cylinders?

Is it possible one cylinder is hypersensitive to timing over all the others?  If so, what might this indicate that doesn't show up on an SB388C or other routine engine examination during annual?

Thanks in advance,

Mark T. Mueller

Tiger N1533R

   	  Quote: 	
		  http://www.matronics.com/Navigator?TeamGrumman-List==================

 [quote][b]

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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teamgrumman(at)yahoo.com
Guest

Posted: Sun Mar 18, 2012 10:08 am Post subject: High CHT on #2 mystery

my guess, Cheetah with JPI

        From: flyv35b <flyv35b(at)minetfiber.com>

 To: teamgrumman-list(at)matronics.com 

 Sent: Sunday, March 18, 2012 6:19 AM

 Subject: Re: High CHT on #2 mystery

 --> TeamGrumman-List message posted by: flyv35b <flyv35b(at)minetfiber.com (flyv35b(at)minetfiber.com)>

On 3/18/2012 5:30 AM, Mark T. Mueller wrote:

 	  Quote: 	
		   Just picked 33R up from annual inspection yesterday, and when flying

 back to my home 'drome I could not keep my #2 CHT under 400 regardless

 of power setting, airspeed, or altitude.  At 3500' and 2600 RPM in level

 cruise with an OAT of 72F #2 hit 440!!!  This was NOT the case before

 annual except in extended climb.  That cylinder is now running a good 30

 - 40 hotter than before annual.  The rest of the cylinders are running

 close to where they were before annual.

 Oil temp stayed below 190.

 I asked my IA what had been done, and he said the only thing he had to

 do was adjust the timing on one mag by a couple degrees and replaced  the

 gasket on that mag.  I have a LASAR ignition, and he allegedly used the

 T-300 tool I provided.

 The SB388C test was done, and he stated was well within tolerance, and

 good comps on all cylinders.

 Prior to annual, the #2 had a much higher EGT than the others, but

 normal CHT.  All four CHTs were within 20+- during normal cruise.  Now

 they are a good 40+ difference between #2 and coolest.  Front cyls have

 always run hotter than rear since my baffling was rebuilt during OH 4

 years ago.

 Now, the obvious answer is my timing is screwed up, but the motor is

 running more smoothly and stronger than ever (smoother than before

 annual) and I don't want to give that up.  In addition, in my experience

 owning 33R it is almost NEVER the "obvious" answer...

 I still have to take a day off work and root  around to see if there was

 any damage to the front baffling when they reassembled the cowling or

 other simple things (I am really hoping it's something simple).

 Looking for ideas.  It is clearly a thermodynamics problem, but what

 might be the best way to approach this without sacrificing the best my

 motor has run in a while?

 Is it possible that low batteries in the T-300 tool might have caused an

 error in adjusting timing?

 What are common baffling issues that might contribute to such a dramatic

 change in #2 CHT without significantly effecting the other cylinders?

 Is it possible one cylinder is hypersensitive to timing over all the

 others?  If so, what might this indicate that doesn't show up on an

 SB388C or other routine engine examination during annual?

 Thanks in advance,

 Mark T.  Mueller

 Tiger N1533R

Is your plane an AG-5B?  Whatp://www.matronics.com/Navigator?TeamGrumman-List" target="_blank">http://                    &nbsp========================

 [quote][b]

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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mark.t.mueller(at)comcast
Guest

Posted: Mon Mar 19, 2012 1:41 am Post subject: High CHT on #2 mystery

 	  Quote: 	
		         Is your plane an AG-5B?  What kind/brand of CHT/EGT instrumentation?              Cliff

1975 AA-5B, VM-1000 Engine Instrument 	
Mark T. Mueller

 Tiger N1533R



  [quote][b]

- The Matronics TeamGrumman-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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