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Cylinder Head Temps

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busdriver

Joined: 16 Jul 2010
Posts: 13
Location: Florida

Posted: Sat Jul 17, 2010 12:47 pm Post subject: Cylinder Head Temps

What should the cylinder head temperatures indicate on a later model AG5B with good seals/ baffles?  Everything I have read says to keep the CHTâ€™s below 400 degrees, but I am not having much success.  #4 is running 420- 430 in the climb with #3 not far behind- I am using a brand new JPI EDM-700 for monitoring.  Iâ€™m climbing full throttle and full rich mixture at 100kts+ airspeed.  Even in cruise, the temps donâ€™t decrease significantlyâ€¦ is this normal for a Tiger?

md11strejo(at)YAHOO.COM
Guest

Posted: Sat Jul 17, 2010 1:14 pm Post subject: Cylinder Head Temps

That sounds about right.  I have a 1976 Tiger,  I've been flying this plane for 10yrs and the temps have always been high.  New engine, baffles 3 yrs ago.  Same temps.  I'm looking at the new cowling Gary has. I have always thought the exit ramps in the cowling are not designed right.  Not enough out flow air.  Just my opinion. 

Scott

N499GT

Sent from my iPhone



On Jul 17, 2010, at 12:47 PM, "busdriver" <clmiller(at)netzero.net> wrote:



 	  Quote: 	
		   

 

 What should the cylinder head temperatures indicate on a later model AG5B with good seals/ baffles?  Everything I have read says to keep the CHTÃ¢â‚¬â„¢s below 400 degrees, but I am not having much success.  #4 is running 420- 430 in the climb with #3 not far behind- I am using a brand new JPI EDM-700 for monitoring.  IÃ¢â‚¬â„¢m climbing full throttle and full rich mixture at 100kts+ airspeed.  Even in cruise, the temps donÃ¢â‚¬â„¢t decrease significantlyÃ¢â‚¬Â¦ is this normal for a Tiger?

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=305217#305217

r.nohr(at)nohrengineering
Guest

Posted: Sat Jul 17, 2010 1:22 pm Post subject: Cylinder Head Temps

Our Grumman easily stays with 350 to 400 degree head temps,,,,,  when we had heating problems after an annual, the problems were from advanced magnito timing... Our grummna seems to advance a bit on timing with hours and wear. . so we have timing carefully checked each annual..  rod

 

 [quote]--

r.nohr(at)nohrengineering
Guest

Posted: Sat Jul 17, 2010 2:20 pm Post subject: Cylinder Head Temps

Our 75 grumman tiger , before we got it 7 or 8 years ago, had a field approval/337 done with a little faring angle added to the cowl.  Supposed to help draw air out....



Also ,, on a big fletchair annual a couple years ago (great people),,,, they found the wrong oil cooler installed,, installed the right one and oil temps have been more to the 350 range rather than 400 since....



rod

 

 [quote]--

teamgrumman(at)YAHOO.COM
Guest

Posted: Sat Jul 17, 2010 9:25 pm Post subject: Cylinder Head Temps

Hi BusDriver,

Thanks for the information.  Most folks with 'high' CHTs never say what or how they are measuring the temps.  

I've done side-by-side testing with a JPI 800 and and EI UBG 16 installed side-by-side.  The EI was set up to monitor the #3 CHT with the JPI monitoring the rest.  Both instruments had there own dedicated circuit breaker and they both used the same ground; the grounding lug on the engine mount.

Before engine start, all EGTs and CHTs read about the same.  Soon after engine start, the JPI started increasing in temp over the EI.  By the time I would get to the run-up area, the CHTs on the EI were 30-40 degrees lower.  In a climb the JPI increased more,  faster, than the EI.  In cruise, I would see as Hi as 80 degrees less on the EI gauge.  

There are several differences between the systems.  

The EI uses a probe that measures the temp of the air in the cylinder head CHT well.

The JPI uses a probe that reaches all the way to the end of the CHT well and actually touches the aluminum.

And, possibly more importantly, 

The EI uses ungrounded probes.

The JPI uses Grounded probes.

If you install just one probe in an EI system, the rest all read a reference temperature; the reference temp is the temp of the monitoring unit itself.  

The problem with using a reference temperature is that the reference temperature doesn't always give an accurate reading.

If you install just one gauge on the JPI, the rest read,  "Open Probe."

I regularly see 450 degrees on climb-out.  450 degrees is about 380-390 on an EI.  

I generally set up for 420 degrees in cruise.  420 degrees is about 350 on an EI.  

If it makes you feel any better, the testing done at Lycoming used ungrounded probes.

Gary

From: busdriver <clmiller(at)netzero.net>

To: teamgrumman-list(at)matronics.com

Sent: Sat, July 17, 2010 1:47:53 PM

Subject: Cylinder Head  Temps



 --> TeamGrumman-List message posted by: "busdriver" <clmiller(at)netzero.net (clmiller(at)netzero.net)>



What should the cylinder head temperatures indicate on a later model AG5B with good seals/ baffles?  Everything I have read says to keep the CHTÃ¢â‚¬â„¢s below 400 degrees, but I am not having much success.  #4 is running 420- 430 in the climb with #3 not far behind- I am using a brand new JPI EDM-700 for monitoring.  IÃ¢â‚¬â„¢m climbing full throttle and full rich mixture at 100kts+ airspeed.  Even in cruise, the temps donÃ¢â‚¬â„¢t decrease significantlyÃ¢â‚¬Â¦ is this normal for a Tiger?





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=305217#305217



http://www.matronics.com/Navigator?TeamG=               - MATRONICS WEB FORUMS target="_blank" href="http://forums.matronics.com">http://forums.matro             - List Contribution Web Site -http://www.ma========================

   



         [quote][b]

busdriver

Joined: 16 Jul 2010
Posts: 13
Location: Florida

Posted: Sun Jul 18, 2010 5:29 am Post subject: Re: Cylinder Head Temps

Thank you for all of the great information- especially the discussion on the differences between EI and JPI probes.  One bit of information I left out- the mags were timed exactly to 25 degrees BTDC (dial indicator/ laser sight etc...)

Thanks again,

Curt

JHOSLER(at)epri.com
Guest

Posted: Sun Jul 18, 2010 8:26 am Post subject: Cylinder Head Temps

Lots has been said about this CHT measurement system or that but what about sensor location?



My experience (1977 Tiger) has been that the spark plug location reads significantly higher than the cylinder head location (probe).  About 30-40 F difference.



John



--

teamgrumman(at)YAHOO.COM
Guest

Posted: Sun Jul 18, 2010 9:07 am Post subject: Cylinder Head Temps

My thought is:  if you can't afford to install the proper equipment to measure the temperatures, don't waste your time and money doing a half-assed job.  There is only one place to measure the cylinder head temperature on a Lycoming.

Some people say, "If a job is worth doing, it's worth doing right."  My corollary is, "If a job isn't worth doing, it isn't worth doing twice."

From: "Hosler, John" <JHOSLER(at)epri.com>

To:  teamgrumman-list(at)matronics.com

Sent: Sun, July 18, 2010 9:25:11 AM

Subject: RE: Cylinder Head Temps

 --> TeamGrumman-List message posted by: "Hosler, John" <JHOSLER(at)epri.com (JHOSLER(at)epri.com)>

Lots has been said about this CHT measurement system or that but what about sensor location?

My experience (1977 Tiger) has been that the spark plug location reads significantly higher than the cylinder head location (probe).  About 30-40 F difference.

John

--

n2_narcosis(at)YAHOO.COM
Guest

Posted: Sun Jul 18, 2010 12:27 pm Post subject: Cylinder Head Temps

As a new owner of a Tiger and not knowing much, I have to ask which monitor would you go with, the EI or JPI?



 Thanks

 Brock 

  

  

 --- On Sun, 7/18/10, Gary Vogt <teamgrumman(at)YAHOO.COM> wrote:



 [quote]

From: Gary Vogt <teamgrumman(at)YAHOO.COM>

Subject: Re: Cylinder Head Temps

To: teamgrumman-list(at)matronics.com

Date: Sunday, July 18, 2010, 12:07 PM



     My thought is:  if you can't afford to install the proper equipment to measure the temperatures, don't waste your time and money doing a half-assed job.  There is only one place to measure the cylinder head temperature on a Lycoming.

 



 Some people say, "If a job is worth doing, it's worth doing right."  My corollary is, "If a job isn't worth doing, it isn't worth doing twice."

 

   From: "Hosler, John" <JHOSLER(at)epri.com>

To: teamgrumman-list(at)matronics.com

Sent: Sun, July 18, 2010 9:25:11 AM

Subject: RE: Cylinder Head Temps



--> TeamGrumman-List message posted by: "Hosler, John" <JHOSLER(at)epri.com (JHOSLER(at)epri.com)>



Lots has been said about this CHT measurement system or that but what about sensor location?



My experience (1977 Tiger) has been that the spark plug location reads significantly higher than the cylinder head location (probe).  About 30-40 F difference.



John



--

teamgrumman(at)YAHOO.COM
Guest

Posted: Sun Jul 18, 2010 4:50 pm Post subject: Cylinder Head Temps

"As a new owner of a Tiger and not knowing much, I have to ask which monitor would you go with, the EI or JPI?



Thanks

Brock"



I like the JPI.  The leads are easier to route.  You can trim to fit them so there isn't a lot of excess wire all over.  The probes are generally faster response.  "I" think the gauge is easier to read and interpret, but, I think that may have to do with not having much time behind the EI.  The connectors behind the unit are smaller and easier to work with.  I've heard over and over how the EI is cheaper.  It's subjective.  Side-by-side, feature-to-feature, the JPI has more of the features I  want already included for the same price.  

Cliff, has has a lot of good luck with EI.  Maybe he can tell us why he prefers it.

Gary



From: Brock Windsor <n2_narcosis(at)YAHOO.COM>

To: teamgrumman-list(at)matronics.com

Sent: Sun, July 18, 2010 1:26:43 PM

Subject: Re: Cylinder Head Temps



 As a new owner of a Tiger and not knowing much, I have to ask which monitor would you go with, the EI or JPI?



 Thanks

 Brock 

  

  

 --- On Sun, 7/18/10, Gary Vogt <teamgrumman(at)YAHOO.COM> wrote:



 [quote]

From: Gary Vogt <teamgrumman(at)YAHOO.COM>

Subject: Re: Cylinder Head Temps

To: teamgrumman-list(at)matronics.com

Date: Sunday, July 18, 2010, 12:07 PM



     My thought is:  if you can't afford to install the proper equipment to measure the temperatures, don't waste your time and money doing a half-assed job.  There is only one place to measure the cylinder head temperature on a Lycoming.

 



 Some people say, "If a job is worth doing, it's worth doing right."  My corollary is, "If a job isn't worth doing, it isn't worth doing twice."

 

   From: "Hosler, John" <JHOSLER(at)epri.com>

To: teamgrumman-list(at)matronics.com

Sent: Sun, July 18, 2010 9:25:11 AM

Subject: RE: Cylinder Head Temps



--> TeamGrumman-List message posted by: "Hosler, John" <JHOSLER(at)epri.com>



Lots has been said about this CHT measurement system or that but what about sensor location?



My experience (1977 Tiger) has been that the spark plug location reads significantly higher than the cylinder head location (probe).  About 30-40 F difference.



John



--

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Sun Jul 18, 2010 5:05 pm Post subject: Cylinder Head Temps

The EI Leads are also trimable to  size.

 [quote]   ---

teamgrumman(at)YAHOO.COM
Guest

Posted: Sun Jul 18, 2010 5:41 pm Post subject: Cylinder Head Temps

Hey Ned, 

How's it going?  How's the cowling?  I expected you to come to Dayton.  What happened?  Did you get the limits fixed on your prop?  Did it change anything noticeable?

The EI leads come shielded and with the terminals in tact.  I thought they needed to be an equal length to get accurate readings between probes.  I must confess, I've never tried to shorten one.  I always figured they needed to stay the length as delivered.

Gary



From: 923te <923te(at)att.net>

To: teamgrumman-list(at)matronics.com

Sent: Sun, July 18, 2010 6:06:15 PM

Subject: Re: Cylinder Head Temps



 ï»¿    DIV { MARGIN:0px;}      The EI Leads are also trimable to  size.

 [quote]   ---

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Sun Jul 18, 2010 7:23 pm Post subject: Cylinder Head Temps

Bummed out about not making the  convention:(

  

 Been able to do some work on the Tiger -  Jaguar.

 Experimented with the right front  baffle and have the CHT's all reading the same (within 1 degree) at lower  altitudes.  Thats at best power level flight at 4500DA with OAT 86 deg  F. All read around 354degF. On climbout was seeing a spread on CHTs 380 to 400  with OAT at 100degF at about 90kts 1250fpm. All this with no air exit at nose  strut....

  

 One oddity I'm not used to seing is that at  some richer settings the CHT's are higher and more uneven than when leaned out.  Any ideas?

  

 Still working on the speed.

  

 Reinstalled the old cowl in order to center  the engine. No small feat;)

 Engine was still down about 3/4" and to the  right about 1". Just like it was before the Jaguar  cowling install

 Found the upper left shock mount bolt had NO  threads showing thru the nut....Tightened to spec'ed torque and checked other 3.  This brought the engine into center of old cowl

 Next project is to center Jag cowl raising it  about 3/4" and moving to left about 1"

 It now flies straight and level hands  free with neutral trim tabs and equal flaps whereas before it tended to  turn to the right.

  

 Allo for now,

 Your Fellow Grumman Enthusiast,

 Ned

  

 PSS SEE PAGE 11 Installation Manual and  elsewhjere EI literature

 http://www.buy-ei.com/Information/II%20-%20UBG-16.pdf

  

"Varying cable lengths will not affect the accuracy of this  instrument."

   [quote][b]

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