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EI vs JPI
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rcmutz(at)msn.com
Guest

Posted: Fri Mar 27, 2009 1:33 pm Post subject: EI vs JPI

I have been following the discussion with interest.

  

 One thing that I don't recall being addressed (maybe Gary addressed in his article) C is C for the limits that Lycoming quotes C which probe did they use for the testing.  One that measures the actual metal temps via conduction C or one that measures the air in a well which is heated by radiation from the hot metal?  Hmmmm...conduction versus radiation?



Richard Mutzman

Windows Live™ SkyDrive: Get 25 GB of free online storage. Check it out.  [quote][b]

GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Fri Mar 27, 2009 8:21 pm Post subject: EI vs JPI

I called Lycoming about 6 years ago and tried to find an engineer who could answer that question. Â It took about 5 'engineers' saying, "Well, [fill in the blank] would know, but, he died." before I realized all of the corporate knowledge was gone. Â I researched it a bit and from what I recall, probes similar to the EI probes were used. 

 

  I also spent a significant amount of time about 20 years ago trying to find out which rocker when where. Â As you may know, the intake rocker and the exhaust rocker are different. Â IAs on my field (Lancaster) and the folks at Lycoming were NO HELP AT ALL. Â I finally found an overhaul manual written in 1955 that described the differences.

 

 

 --

_________________
Gary
AuCountry Aviation
Home of Team Grumman

az_gila

Joined: 17 Jun 2006
Posts: 99
Location: Tucson, AZ

Posted: Fri Mar 27, 2009 11:27 pm Post subject: EI vs JPI

I believe you can deduce what they used from their documents.



 The Lycoming Overhaul Manual Test Run section specifically calls for a 500F max CHT limit (table on page 9-2 of my 2002 version) and states that it is at the "Bayonet Location".



 Lycoming documents don't change too much over time...:^) ...and the reference to Bayonet says to me that they use a "Bayonet Probe" when they do certification runs.



 Older instrumentation in the 60's was MIL-Spec AN type that got replaced by the MS specifications - but remained basically the same part.



 I have a copy of the 1966  MS 90324 Specification "Thermocouple, Engine Cylinder, Bayonet Type"



 It is definitely a spring loaded device with a 2.5 pound spring force specification at a length of 2.5 inches.  With the AN 4076-1 bayonet adapter, it is tested in a test fixture with a depth of 1.80 inches.



 Can someone measure the depth of a Lycoming CHT well - I bet it is 1.8 inches deep, or a bit less....:^)



 I say that the use of the word "Bayonet", along with the MIL-Spec standards from the 50s and 60s when our engines were basically certified say that it is a spring loaded device that physically touches the bottom of the CHT well.



 Sacramento Sky ranch has a probe picture here -



  http://www.sacskyranch.com/acatalog/86251.jpg



 The AN 4076 adapter picture is here -



  http://www.aircraftspruce.com/catalog/inpages/inmisc/28202.jpg



 I think it's all in the word "bayonet"....



 gil - the detective...:^)



 

 At 09:21 PM 3/27/2009, teamgrumman(at)aol.com wrote:

 [quote]I called Lycoming about 6 years ago and tried to find an engineer who could answer that question. Â It took about 5 'engineers' saying, "Well, [fill in the blank] would know, but, he died." before I realized all of the corporate knowledge was gone. Â I researched it a bit and from what I recall, probes similar to the EI probes were used. 



 I also spent a significant amount of time about 20 years ago trying to find out which rocker when where. Â As you may know, the intake rocker and the exhaust rocker are different. Â IAs on my field (Lancaster) and the folks at Lycoming were NO HELP AT ALL. Â I finally found an overhaul manual written in 1955 that described the differences.



 

 --

flyv35b(at)minetfiber.com
Guest

Posted: Sat Mar 28, 2009 6:21 am Post subject: EI vs JPI

I called Lycoming about 6 years ago and tried to find an engineer who could  answer that question.  It took about 5 'engineers' saying,  2Well, [fill in  the blank] would know, but, he died. 2 before I realized all of the corporate  knowledge was gone.  I researched it a bit and from what I recall, probes  similar to the EI probes were used. 

  

 I would have guessed the other style  (spring loaded) as that is what Alcor used years ago on their analog instruments  before JPI or EI were even in existence.

  

 I also spent a significant amount of time about  20 years ago trying to find out which rocker when where.  As you may know,  the intake rocker and the exhaust rocker are different.  IAs on my field  (Lancaster) and the folks at Lycoming were NO HELP AT ALL.  I finally found  an overhaul manual written in 1955 that described the  differences.



 The older engines had a small hole in the exhaust rocker arm  that which was supposed to squirt a little oil through the valve spring and on  to the valve stem, if you can believe that.  Bill Marvel discovered that an  engine that he had recently had overhauled by Lycoming had the intake and  exhaust rocker arms reversed and he had badly worn exhaust guides in a short  time (less than 250 hrs as I recall).  He wrote a letter to the president  of Lycoming about it and they gave him a complete new engine.  I think it  was as a result of this that Lycoming then changed to use the same exhaust  rocker arm on both the intake and exhaust - so they could not be mixed up by  someone not paying attention.  But there are thousands of the older style  rocker arms out there in use still, probably many more than there are the later  configuration.  A much better solution was developed when the IO-540 engine  in new Mooneys were wearing out the exhaust guides in 200-400 hrs and the owners  where bitching so bad that Mooney put enough pressure on Lycoming to find a  solution and not just blame it on operator technique!  Same cylinder and  head as the O-360 engine uses but Lycoming never would admit they had a problem  with any engine besides the specific Mooney model and they would not sell the  parts for retrofit for other engines.  But that's the attitude when the  attorneys and bean counters are calling the shots.

  

 Cliff

 [quote]   ---

flyv35b(at)minetfiber.com
Guest

Posted: Sat Mar 28, 2009 6:44 am Post subject: EI vs JPI

I think you're right about this Gil.  If so and  if there really is a large difference between the temperatures measured by a JPI  EDM700/800 and an EI instrument with the different style probes then it really  does matter which  2system 2 most accurately represents what Lycoming measured and  set the 500F redline limit by and their statement that for long life the max  operating temp should be 400F.  If you believe that the JPI instrumentation  most accurately represents Lycoming's testing and that EI reads 50F lower, say,  then you should limit your continuous CHTs to 350F if you are using EI  instrumentation.  I'll bet there are many many Tigers out there that are  unable to do this unless operated with excessively rich mixtures to get the  extra cooling needed to keep the temps this low.

  

 Cliff

 [quote]   ---

GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Sat Mar 28, 2009 9:36 am Post subject: EI vs JPI

OK, but, it doesn't say what type probe, K, etc, or if it was grounded or not. Â 

  	  Quote: 	
		  Lycoming documents don't change too much over time...:^) ...and the reference to Bayonet says to me that they use a "Bayonet Probe" when they do certification runs. 	


 

 

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_________________
Gary
AuCountry Aviation
Home of Team Grumman

az_gila

Joined: 17 Jun 2006
Posts: 99
Location: Tucson, AZ

Posted: Sat Mar 28, 2009 4:36 pm Post subject: EI vs JPI

Yep... but doesn't Lycoming really set 450F as a "Climb out" redline in their later "making your engine last" documents? 



 The 400F number is a max cruise temp.....  gil A



 At 07:42 AM 3/28/2009, flyv35b wrote:

 [quote]I think you're right about this Gil.  If so and if there really is a large difference between the temperatures measured by a JPI EDM700/800 and an EI instrument with the different style probes then it really does matter which "system" most accurately represents what Lycoming measured and set the 500F redline limit by and their statement that for long life the max operating temp should be 400F.  If you believe that the JPI instrumentation most accurately represents Lycoming's testing and that EI reads 50F lower, say, then you should limit your continuous CHTs to 350F if you are using EI instrumentation.  I'll bet there are many many Tigers out there that are unable to do this unless operated with excessively rich mixtures to get the extra cooling needed to keep the temps this low.

  

 Cliff

   ---

az_gila

Joined: 17 Jun 2006
Posts: 99
Location: Tucson, AZ

Posted: Sat Mar 28, 2009 5:22 pm Post subject: EI vs JPI

Gary ....Not really relevant to the discussion.  



 The debate is "Did the original Lycoming certification probe touch the sell of the cylinder?"



 The MS90324 specification defines a Type J thermocouple  (iron-constantan) that is ungrounded and has a 0.025 ohm resistance, and does touch the base of the cylinder well.  



 This the only Mil-Spec engine CHT thermocouple probe listed.



 I'm sure Lycoming would have used the MS part (or it's earlier AN5541 equivalent) 



 Alcor think the bayonet type are better - from their STC



 --------------------------------------

 Spring loaded bayonet types are more accurate than simple screw

 in types because the probe touches the bottom of the thermowell and senses metal rather

 than air temperature.

 --------------------------------------



 ....and, no surprise, the Alcor bayonet probe is type J and has the same resistance as the old MS90324 specification.



 If you want to know lots of details on thermocouples, including a DIY sensor, this is interesting....



  http://www.aeroelectric.com/articles/excerpt.pdf



 gil A



 



 

 At 10:32 AM 3/28/2009, you wrote:

 [quote]OK, but, it doesn't say what type probe, K, etc, or if it was grounded or not. Â 

   Lycoming documents don't change too much over time...:^) ...and the reference to Bayonet says to me that they use a "Bayonet Probe" when they do certification runs.



  



 

 --

rcmutz(at)msn.com
Guest

Posted: Sun Mar 29, 2009 5:57 am Post subject: EI vs JPI

Gil C

  

 I tend to agree with what you are saying.  It does appear that Lycoming used the spring loaded type probe which touches the metal.  Therefore it seems logical that if one uses a probe that touches the metal (whether EI or JPI and installed correctly C common or floating ground) C observes the temp limits of 500 and 400 C one should be ok from a cylinder durability perspective.  At least from the temp side of the durability "equation".  

  

 Thanks for dong the research on this.  When I put in a CHT system C I will use the bayonet type probe C independent of JPI or EI electronics.



Rich

Hotmail® is up to 70% faster. Now good news travels really fast. Find out more.  [quote][b]

GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Sun Mar 29, 2009 10:42 am Post subject: EI vs JPI

This is only true if, and it's a big IF, the temperatures displayed on todays instrumentation "WOULD" have displayed the same temperatures as those recorded by Lycoming techniciansÂ on the instrumentation used by Lycoming. Â  

 

  I don't care what Lycoming's results were. Â I don't care what system Lycoming used, grounded or ungrounded, J or K type probes, etc., whenever it was they did their testing. Â We don't even know if they tested to destruction. Â OR. Â Did they just get out a metallurgy handbook and look at aluminum properties and pick a limit from there? Â 

  

 

  There are so many 'old wives' tales regarding how to operate EGTs and CHTs and so many recommendations that contradict each other that I'm not convinced any of them are true. Â I would like to see Lycoming step up to the plate and do their own testing and comparisons with todays instrumentation. Â Even if I had the same MIL spec probes Lycoming supposedly used, there is no guarantee that I'd see the same temperatures Lycoming did under the same conditions. Â THE ONLY THING I COULD BE SURE OF, using the exact same instrumentation Lycoming did, IS A VIABLE REASON FOR WARRANTEE WORK FROM LYCOMING should a cylinder fail.

  

 

  It is obvious, at least to me, that JPI and EI instrumentation give dramatically different temperature read-outs. Â Is it just the probe? Â Is it the difference between grounded or ungrounded thermal couples?

  

 </  div>  My personal upper CHT limit on climb out, on the JPI 800, is 470 degrees. Â WHY? Â Because, under the same conditions, I saw 390-400 on the EI sitting next to my JPI (do back off on power at 440 and lower the nose to keep it below 450). Â My high power, 2700 rpm, cruise limit is 425 (350 on an EI). Â I expect to see something in the neighborhood of 380 degrees (320 on an EI) at 65% power and 8500 feet. Â 

  

 

  Speaking of 'old wives' tales: Â Why do we have such strict limitations on tear-down and inspection if an engine is operated over 2700 rpm? Â Where did the 2700 rpm limit come from? Â Why is there a 2700 rpm limit on airplane engines and a 2900 to 3200 rpm limit on similar engines used in helicopters? Â 

 

 

 --

_________________
Gary
AuCountry Aviation
Home of Team Grumman

az_gila

Joined: 17 Jun 2006
Posts: 99
Location: Tucson, AZ

Posted: Sun Mar 29, 2009 11:03 am Post subject: EI vs JPI

 	  Quote: 	
		  This is only true if, and it's a big IF, the temperatures displayed on todays instrumentation "WOULD" have displayed the same temperatures as those recorded by Lycoming techniciansÂ on the instrumentation used by Lycoming. Â  

 	


 Gary... I don't belief that is a big "IF"...



 The electrical characteristics of a type J thermocouple have been well known from long before WWII.



 The electrical instrumentation bit has not changed over the years as far as the basic thermocouple, especially when used in an engine test cell.  I bet Lycoming had individual CHT meters directly connected to the probes, none of this fancy digital switching, scanning stuff....:^)



 Today the probes and the interconnect may be different, but the a type J thermocouple has always created the same amount of voltage due to physics.



 There is something else going on here in your plane - and since we are dealing with fractions of milliVolts, I would personally vote for grounding issues.  You can see from the table below that 10 degrees Centigrade is about a 1/2 milliVolt change.  Try a direct wire from GND on your EI gauge to the engine.



 This is from Sandia labs...  gil A



 

 [quote] ITS-90 Table for type J  thermocouple  °C      0      1      2      3      4      5      6      7      8      9     10                                 Thermoelectric Voltage in mV       0  0.000  0.050  0.101  0.151  0.202  0.253  0.303  0.354  0.405  0.456  0.507   10  0.507  0.558  0.609  0.660  0.711  0.762  0.814  0.865  0.916  0.968  1.019    20  1.019  1.071  1.122  1.174  1.226  1.277  1.329  1.381  1.433  1.485  1.537    30  1.537  1.589  1.641  1.693  1.745  1.797  1.849  1.902  1.954  2.006  2.059    40  2.059  2.111  2.164  2.216  2.269  2.322  2.374  2.427  2.480  2.532  2.585       50  2.585  2.638  2.691  2.744  2.797  2.850  2.903  2.956  3.009  3.062  3.116   60  3.116  3.169  3.222  3.275  3.329  3.382  3.436  3.489  3.543  3.596  3.650    70  3.650  3.703  3.757  3.810  3.864  3.918  3.971  4.025  4.079  4.133  4.187    80  4.187  4.240  4.294  4.348  4.402  4.456  4.510  4.564  4.618  4.672  4.726    90  4.726  4.781  4.835  4.889  4.943  4.997  5.052  5.106  5.160  5.215  5.269      100  5.269  5.323  5.378  5.432  5.487  5.541  5.595  5.650  5.705  5.759  5.814  110  5.814  5.868  5.923  5.977  6.032  6.087  6.141  6.196  6.251  6.306  6.360   120  6.360  6.415  6.470  6.525  6.579  6.634  6.689  6.744  6.799  6.854  6.909   130  6.909  6.964  7.019  7.074  7.129  7.184  7.239  7.294  7.349  7.404  7.459   140  7.459  7.514  7.569  7.624  7.679  7.734  7.789  7.844  7.900  7.955  8.010      150  8.010  8.065  8.120  8.175  8.231  8.286  8.341  8.396  8.452  8.507  8.562  160  8.562  8.618  8.673  8.728  8.783  8.839  8.894  8.949  9.005  9.060  9.115   170  9.115  9.171  9.226  9.282  9.337  9.392  9.448  9.503  9.559  9.614  9.669   180  9.669  9.725  9.780  9.836  9.891  9.947 10.002 10.057 10.113 10.168 10.224   190 10.224 10.279 10.335 10.390 10.446 10.501 10.557 10.612 10.668 10.723 10.779      200 10.779 10.834 10.890 10.945 11.001 11.056 11.112 11.167 11.223 11.278 11.334  210 11.334 11.389 11.445 11.501 11.556 11.612 11.667 11.723 11.778 11.834 11.889   220 11.889 11.945 12.000 12.056 12.111 12.167 12.222 12.278 12.334 12.389 12.445   230 12.445 12.500 12.556 12.611 12.667 12.722 12.778 12.833 12.889 12.944 13.000   240 13.000 13.056 13.111 13.167 13.222 13.278 13.333 13.389 13.444 13.500 13.555      250 13.555 13.611 13.666 13.722 13.777 13.833 13.888 13.944 13.999 14.055 14.110  260 14.110 14.166 14.221 14.277 14.332 14.388 14.443 14.499 14.554 14.609 14.665   270 14.665 14.720 14.776 14.831 14.887 14.942 14.998 15.053 15.109 15.164 15.219   280 15.219 15.275 15.330 15.386 15.441 15.496 15.552 15.607 15.663 15.718 15.773   290 15.773 15.829 15.884 15.940 15.995 16.050 16.106 16.161 16.216 16.272 16.327        [quote][b]

GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Sun Mar 29, 2009 4:40 pm Post subject: EI vs JPI

 	  Quote: 	
		  There is something else going on here in your plane - and since we are dealing with fractions of milliVolts, I would personally vote for grounding issues.Â  	
MY PLANE? Â Ok, maybe your right. Â The grounds in installed according to the STC were done wrong. Â Maybe the probes grounding against brand new cylinders had corrosion built up in them. Â  

 

  Maybe planes experiencing CHT readings higher on a JPI than on an EI also followed the installation instructions.

 

   

 

  How about you doing your own testing and report your own results?

 

 

 --

_________________
Gary
AuCountry Aviation
Home of Team Grumman

az_gila

Joined: 17 Jun 2006
Posts: 99
Location: Tucson, AZ

Posted: Sun Mar 29, 2009 5:42 pm Post subject: EI vs JPI

Gary,



 How many STCs have you installed with poor/bad/wrong instructions?  And the CHT/EGT monitor STCs are quite "generic" not really airframe specific.



 My latest one was my Plane Power voltage regulator.  Works fine, but needed spacers to clear the "bumps" on the fire wall - hardly a drop-in exact replacement for the non flat bottom mechanical regulator - and no mention in the STC instructions.



 Your plane seems to be the only test case reporting the problem.  I'm happy with the Insight GEM in mine with it's probes that touch the thermowell bottom like I believe the Lycoming test bayonet probes did during their certification.



 As an electronics engineer, I know I would not design sensitive millivolts equipment using grounded sensors.... but that's just me.... and my stuff is (or has been) working in military aircraft and space vehicles....:^)



 gil A



 PS ...I like the GEM unit, but I have the "bars only" version - I would prefer the version with numbers - a probable future upgrade.



 PPS  Sorry about the formatting of the mV chart in my previous e-mail



 Here is an alternate link to another table of National Institute of Standards and Technology output voltages from a Type J thermocouple -



  http://www.omega.com/temperature/Z/pdf/z203.pdf



 This shows how small the DC voltages are that we are measuring.



 At 05:40 PM 3/29/2009, you wrote:

 [quote]  There is something else going on here in your plane - and since we are dealing with fractions of milliVolts, I would personally vote for grounding issues.Â 



  MY PLANE? Â Ok, maybe your right. Â The grounds in installed according to the STC were done wrong. Â Maybe the probes grounding against brand new cylinders had corrosion built up in them. Â  



 Maybe planes experiencing CHT readings higher on a JPI than on an EI also followed the installation instructions.



 How about you doing your own testing and report your own results?



 

 --

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Sun Mar 29, 2009 6:04 pm Post subject: EI vs JPI

I started this thread because of similar  thread that was started on the GG. I understood one poster to say that he too  had experienced higher readings with JPI type probes that actually touch the  thermowell. He had both in his Cheetah and found that the probes that touch the  head actually give a higher reading.

  

 So in answer to Gil's post it appears that  others have noted the diffenece in temp readings besides Gary.

  

 Someone at Lycoming needs to answer this  question, at least the question of the type of probe they used. Right now we are  just speculating on what type of probe they used.

  

 Ned

  

 Here is the post I refer to:

  

   

 ---

az_gila

Joined: 17 Jun 2006
Posts: 99
Location: Tucson, AZ

Posted: Sun Mar 29, 2009 6:14 pm Post subject: EI vs JPI

Ned... I believe the GG post you refer to still references Gary's EI/JPI measurements....:^)



 He just says below that the EI non-bayonet probes read lower - which does not seem to be in dispute....:^)



 And do you really think Lycoming used a non-MIL-Spec probe, especially in the 60's, for certification?  I vote for probes that touch the cylinder.



 gil A



 At 07:05 PM 3/29/2009, you wrote:

 [quote] I started this thread because of similar thread that was started on the GG. I understood one poster to say that he too had experienced higher readings with JPI type probes that actually touch the thermowell. He had both in his Cheetah and found that the probes that touch the head actually give a higher reading.

  

 So in answer to Gil's post it appears that others have noted the diffenece in temp readings besides Gary.

  

 Someone at Lycoming needs to answer this question, at least the question of the type of probe they used. Right now we are just speculating on what type of probe they used.

  

 Ned

  

 Here is the post I refer to:

  

  

 ---

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Sun Mar 29, 2009 6:32 pm Post subject: EI vs JPI

Here is another example given on the GG of  others that have found the same as Gary.

 [quote]           Subject: Re: JPI vs EI probes      
From:      
Date: Wed, 09 Jan 2008 15:59:45 -0500 
     	  Quote: 	
		  Had I not had 200 hours on my Tiger with the JPI and KNOWN that the #3

cylinder was within a few degrees of cylinder #4, I would have to agree.

B Yes, had I not had previous experience with my engine and the JPI, and yes

IF I installed the EI into an unknown condition, then yes, one could say that

one cylinder runs 80 degrees cooler than the others. But, that is not the

case. 

For what it's worth, the testing on the new cowling is being done with EI

gauges, calibrated by EI for the FAA. These probes are calibrated to read

within 1 degree. These also show, on the average, on ALL 4 CYLINDERS, 50 to

80 degrees cooler than the data downloaded from the JPI. Different plane.

B Different engine. Different baffles. And 50 to 80 degrees difference in

temps.

I talked to JPI. Their probes and analyzers are calibrated to within 1

degree.

Mount a JPI CHT probe in a piece of steel 4 inches thick simulating the

mounting in a cylinder. Mount the EI gauge in a hole in the steel. Heat

the other side with a torch. You'll get different readings. 

LyCon has a customer in Wyoming (Wildoming) with a Husky. He changed from EI

to JPI after and engine overhaul. He chased around 70 degree higher temps

for a long time. And by chasing, I mean they pulled the engine and sent it

back to LyCon for inspection. LyCon ran the engine without baffles and it

was never over 380. They concluded the JPI must read higher. I had talked

to Ken in the past about doing a side-by-side test of JPI and EI. Never

done. We talked when his customer sent the engine back. 

I installed a JPI 700 in a Comanche following an engine overhaul. The engine

overhaul was a complete firewall forward with all new baffles and seals. The

owner complained of temps going over 450 on climb-out. I couldn't convince

him it was the analyzer and not his engine. I just heard that he recently

had the EI re-installed. He couldn't deal with seeing the temps going over

450 on climb-out. He told me that he now sees temps in the 380 range and he

likes that better. 

Both readings of temperature are correct. They are measuring different

temperatures. One measures the temp of the air in the well, the other

measures the temperature of the aluminum.

[b]

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Sun Mar 29, 2009 6:33 pm Post subject: EI vs JPI

Gil,

  

 I'm confused by your post below.

 Don't you mean for Gary to try a direct wire  from GND on you JPI gauge to the engine?

  

 As EI are not grounded probes....

  

 ned

  

  

  

  

  

  

 There is something else going on here in your plane - and since we are  dealing with fractions of milliVolts, I would personally vote for grounding  issues.  You can see from the table below that 10 degrees Centigrade is  about a 1/2 milliVolt change.  Try a direct wire from GND on your EI gauge  to the engine.



This is from Sandia labs...  gil  A

   [quote][b]

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Sun Mar 29, 2009 6:33 pm Post subject: EI vs JPI

Perhaps there was a milspec probe like the one  EI uses today in use on Lycomings certification tests...

  

 Like Isaid earlier we are just  speculating

 [quote]   ---

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Sun Mar 29, 2009 6:33 pm Post subject: EI vs JPI

Gil,

  

 You didn't read the post very well. I removed  all but the one sentence from the post that you missed. Want to change your  belief?

 Ned

  

 ---

flyv35b(at)minetfiber.com
Guest

Posted: Sun Mar 29, 2009 6:35 pm Post subject: EI vs JPI

Maybe you guys need to ask Steve Peach about the two different styles of EI probes, bayonet and standard P-100, that he tested and found very little difference between the two.  The large differences in temperature mentioned are between JPI with the bayonet and EI with the fixed probe.  And all the accusations, or implications at least, are that the fixed EI probe does not measure the true temperature.  There is a real possibility that it could be due to something completely different.



Cliff

  ---

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