---------------------------------------------------------- JabiruEngine-List Digest Archive --- Total Messages Posted Wed 04/26/06: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:01 AM - Re: engine monitor problem - CHT thermocouples (T. Graziano) 2. 07:27 AM - Re: Re: engine monitor problem (JAPhillipsGA@aol.com) 3. 07:56 AM - Re: Re: engine monitor problem - CHT thermocouples (JAPhillipsGA@aol.com) 4. 04:23 PM - Re: engine monitor problem (Jim Stone) ________________________________ Message 1 _____________________________________ Time: 06:01:17 AM PST US From: "T. Graziano" Subject: JabiruEngine-List: Re: engine monitor problem - CHT thermocouples --> JabiruEngine-List message posted by: "T. Graziano" Bill, If your CHT probes are attached to your monitoring instrument, then all you ahouls have to do is put the "sensening" end of the probe into a know temp liquid and check your instrument reading. I used to check calibration by placing the "twisted" end of the thermocouple wire into ice water (32 deg F/0 deg C) and then into boiling water. Another thing to do to check the CHT thermocouple position for instrument reading is to use a hair dryer or other hot air device to put heat onto the cylinder and check the reading on the instrument. I found that I had two cylinder location readings reversed when I installed my probes. Tony Graziano ZodiacXL/Jab3300A, N493TG, 91 hrs Time: 09:34:00 AM PST US From: JAPhillipsGA@aol.com Subject: Re: JabiruEngine-List: Re: engine monitor problem --> JabiruEngine-List message posted by: JAPhillipsGA@aol.com Jim, I think I will try to test my probes as you suggested. Again, how would you do that ? I have a digital thermometer so would I have to get some water hot and stick the thermometer probe and the CHT probe in there together and see the difference in readings ? You mention grounding. Would I have to run a ground wire from the CHT probe to the engine ? I remember when I purchased the CHT kit the instructions mentioned that they could be off by as much as 75 degrees. Best to you, Bill of Georgia, N505WP, 601X-3300 w/dc and 60 plus hours ________________________________ Message 2 _____________________________________ Time: 07:27:38 AM PST US From: JAPhillipsGA@aol.com Subject: Re: JabiruEngine-List: Re: engine monitor problem --> JabiruEngine-List message posted by: JAPhillipsGA@aol.com Jim, thanks for the input. I plan to try testing this weekend at the hanger. What kind of difference did you find ? and did you check all your CHT probes or just the hottest ? I don't want to make extra work for myself as every minute working - is a minute flying, Thanks, Bill of Georgia do not archive ________________________________ Message 3 _____________________________________ Time: 07:56:51 AM PST US From: JAPhillipsGA@aol.com Subject: Re: JabiruEngine-List: Re: engine monitor problem - CHT thermocouples --> JabiruEngine-List message posted by: JAPhillipsGA@aol.com Tony, thanks for the input. I to had two cylinders probes reversed. My real concern is how much attention I need to pay to the gages. I noticed the other day that my oil temp went up as the CHTs for 4 & 6 stayed up and moved down as they went down. I wonder how accurate my oil temp gage is ? Is there a way to mechanically test this ? When I first started flying her I used a mechanical gage to test the oil pressure gage and found it reading 10-15 pounds high. Have you tested yours ? I will be glad to send you the oil gage I used and fittings if you want. Thanks again, Bill of Georgia do not archive ________________________________ Message 4 _____________________________________ Time: 04:23:48 PM PST US Subject: JabiruEngine-List: Re: engine monitor problem From: "Jim Stone" --> JabiruEngine-List message posted by: "Jim Stone" My tests were more complex then you would typically encounter. This was because I was testing a custom design before general public release. The firt set of softeware coefficients gave results that were nowhere near the real worlk, Ref temp = 385 'F vs displayed value = 223' F. variation between sensors varied by up to 20% of reference standard. We eventually scrapped the initial hardware and went to differential sensors for each line. The process took several months between hardware and software revisions. All sensors are now +/- 3% of my calibrated reference. The Great Lakes sytsem has enough volume that I would expect all sensors to show in the range of +/- 5% compared to a reference standard. -------- Jim Stone Jabiru J450 N450SJ Clearwater FL USA Read this topic online here: http://forums.matronics.com/viewtopic.php?p=30960#30960