Garwin cluster

[DonMuncy]

3 hours ago, MyNameIsNobody said:

It is NOT about enjoyment.  It is about upgrading to a digital read-out that provides a superior (accuracy) and upgraded aesthetic appearance that is functional better.  

Can one "scan" a CHT reading of 378 degrees. At a glance you can see an analog is a little under 400. I agree there are time when you want to know within a few units, but other times you want to scan for unusual readings.

[Guest]

1 hour ago, bonal said:

Its funny this thread was mostly ignored until there was a problem I thank all for the suggestions and will check cannon plug today as far as the digital anolog debate I just want to get my pressure working again as this is what my budget allows. It's a double edged sword the more data you have the more you scratch your head trying to analyze it. This engine has flown over 6000 hrs  as equipped and oil temp is a pretty straight forward bit of information. Believe me when I say when things need repair I have spent whatever it takes to fly safe.

They are indeed a double edged sword, they do provide a ton more information.  Lots of dollars have been spent putting them in, and many more dollars are spent analyzing the readings.

Clarence

[N601RX]

I would also say that they have saved many dollars by pointing you directly to the problem.

[Marauder]

I would also say that they have saved many dollars by pointing you directly to the problem.

For me, the original GEM I had in the 1990s, saved fuel and once saved my bacon by letting me know what was going on with my engine while it was having problems.

[Mooneymite]

Technology always seems to create one problem for every problem it solves.  The airlines went nuts over BITE....built in test equipment.  The theory was when something broke, the machine would tell you what was broken.  However the problem arose that when the BITE said something was broken, you never knew if it was it the item it monitored, or the BITE!  

Twice the complexity!  

[Browncbr1]

After reading this thread recently, I decided to monitor my garwin cluster a little more closely in cross reference to my jpi 830.   I found that my factory cht indicated about 280F (#3) while my #3 jpi indicated 370F on takeoff.  I am starting to doubt that the numb-nuts who installed my jpi plugged leads into the wrong holes in the DB connectors.  I had already found that the oil temp lead was in the wrong spot and had to be moved over one place.  You would think that a licensed IA would have atleast noticed something was wrong by the giant red X on the oil temp field when doing the final system checklist.    

[par]

1 hour ago, Browncbr1 said:

After reading this thread recently, I decided to monitor my garwin cluster a little more closely in cross reference to my jpi 830.   I found that my factory cht indicated about 280F (#3) while my #3 jpi indicated 370F on takeoff.  I am starting to doubt that the numb-nuts who installed my jpi plugged leads into the wrong holes in the DB connectors.  I had already found that the oil temp lead was in the wrong spot and had to be moved over one place.  You would think that a licensed IA would have atleast noticed something was wrong by the giant red X on the oil temp field when doing the final system checklist.    

Regarding your CHT reading difference on #3, this can be attributed to the type and location of the probe used on for the digital indicator. If it is located around the spark plug, the value read will be higher than the value you will see from using a CHT probe in the cylinder. I'll have to look it up but I think my book said it can be higher by as much as 100 degrees.

[carusoam]

Two different sensors mounted in two different locations on the same cylinder...

The ship's gauge is supposed to stay in the proper location, the JPI TC is sometimes mounted using a spark plug ring TC.  The spark plug ring TC is much hotter based the location it is reading.

The better alternative is a ring TC that mounts under the ship's TC's bayonet holder.  It is a lesser known alternative, accept around here.

Which two TCs do you have for CHT #3 and why?

Best regards,

-a-

[MyNameIsNobody]

20 hours ago, DonMuncy said:

Can one "scan" a CHT reading of 378 degrees. At a glance you can see an analog is a little under 400. I agree there are time when you want to know within a few units, but other times you want to scan for unusual readings.

I have both.  EI has lighted dots that give you a good quick scan reference (They just don't vary if all is well) and there is a digital value that is EXACT.  Individual EI instruments are NOT that pricey.  You can do one or two a year until done.  In addition to MP/RPM/OIL PRES&TEMP VOLTS&AMPS you get a fuel flow and clock and are golden.  An old GEM (basically free) and some new probes and you have a four probe BETTER exhaust/cylinder reference.  You don't have to spend thousands for flat screen color.  Certified can be done on a budget.  I still had enough panel space for a panel mount 696...

[Browncbr1]

14 hours ago, par said:

Regarding your CHT reading difference on #3, this can be attributed to the type and location of the probe used on for the digital indicator. If it is located around the spark plug, the value read will be higher than the value you will see from using a CHT probe in the cylinder. I'll have to look it up but I think my book said it can be higher by as much as 100 degrees.

I'm using a collar probe that is located on the factory CHT probe and tanis probes on other cylinders.  If it were on the spark plug, I wouldn't be wondering what I'm wondering..

[DonMuncy]

14 minutes ago, Browncbr1 said:

I'm using a collar probe that is located on the factory CHT probe and tanis probes on other cylinders.  If it were on the spark plug, I wouldn't be wondering what I'm wondering..

It seems t0 me that using "piggy back" collar on a probe should read a little different than a probe, which presumably reads at the "bottom" of the well. Having all your sensors reading off the spark plug base should be OK, as would all reading in the "well", as would reading all in the piggy-back mode. I think that technically, a different temperature would apply to each measurement location. What drives us crazy is having different ones reading different places, and trying to make sense of the different numbers.

[Browncbr1]

24 minutes ago, DonMuncy said:

It seems t0 me that using "piggy back" collar on a probe should read a little different than a probe, which presumably reads at the "bottom" of the well. Having all your sensors reading off the spark plug base should be OK, as would all reading in the "well", as would reading all in the piggy-back mode. I think that technically, a different temperature would apply to each measurement location. What drives us crazy is having different ones reading different places, and trying to make sense of the different numbers.

Yea, all of my JPI CHT probes are piggy back on the "wells"   But, what caught my eye is that there is nearly a 100 degree delta between factory and JPI on #3.  JPI claims collars that go on the "wells" are generally 20dF lower than actual reading deep in the well.  But, my JPI is telling me it is nearly 100 hotter at the collar.  It seems that either my factory gauge is faulty or the AI who installed my JPI mixed up the cylinder numbers..   #3 on the JPI is always the hottest... I'm going to check all leads at annual next month.

[carusoam]

Accuracy of the gauges and TC locations should all read the same number (within reason) at room temperature...

if one of them is really off after a day, it is possible to calibrate the gauge to make an adjustment for what it is telling.

To know what the TC is telling it is often calibrated by placing it in water with excess ice.  Then finishing the test by putting the sensors in boiling water.  Compare to known values at your altitude...

PP knowledge, I'm not a mechanic...

Best regards,

-a-

[Marauder]

24 minutes ago, DonMuncy said: It seems t0 me that using "piggy back" collar on a probe should read a little different than a probe, which presumably reads at the "bottom" of the well. Having all your sensors reading off the spark plug base should be OK, as would all reading in the "well", as would reading all in the piggy-back mode. I think that technically, a different temperature would apply to each measurement location. What drives us crazy is having different ones reading different places, and trying to make sense of the different numbers.

Yea, all of my JPI CHT probes are piggy back on the "wells"   But, what caught my eye is that there is nearly a 100 degree delta between factory and JPI on #3.  JPI claims collars that go on the "wells" are generally 20dF lower than actual reading deep in the well.  But, my JPI is telling me it is nearly 100 hotter at the collar.  It seems that either my factory gauge is faulty or the AI who installed my JPI mixed up the cylinder numbers..   #3 on the JPI is always the hottest... I'm going to check all leads at annual next month.

When I had the JPI 830, the #3 cylinder had the piggy back probe installed. I found the temp to be slightly warmer than the other cylinders that had the probes installed in the cylinder well ports. The factory gauge, although analog, was reporting a reasonable temp in comparison.

When I upgraded to the 900, the probes for the other 3 cylinders were kept in the wells and the #3 was replaced with a direct well probe (the factory gauges were removed). The temps remained consistent with the 830 readings, that is to say, with the #3 reporting a little higher than the other temps.

[wombat]

Marauder:  Is the "22.0 USD" showing on the 830 the gas bill for the flight so far?   

[Marauder]

Marauder:  Is the "22.0 USD" showing on the 830 the gas bill for the flight so far?   

Back in 1991 it wasn't far off. Now I need to use a multiplier

[bonal]

On March 27, 2016 at 6:27 PM, carusoam said:

Open, Clean and re-connect the plug... We love Aviation electronics...

Best regards,

-a-

Ended up being the connector to the probe. It was cracked and had some pretty bugered up repairs done at some point. New connector and wires installed today. Test run up yielded normal temps hopefully next flight will confirm service complete