Is 310 deg. F. a HI CHT??

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bkspero

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bkspero
Finally seem to have gottem most of the kinks out of a new EI CGR-30P engine analyzer and decided to try out the free version of Mike Busch's SavvyAnalysis.com performance analysis tool. There is an "Alerts" column on the My Flights page (where the file names are listed), and both of my flights, with peak cylinder temperatures of about 310 deg. F., showed up with a "HI CHT" alert. I thought that CHT's in this range were on the low end of normal. What am I missing?

Here are more details. I flew the two uploaded flights at relatively low power levels ( ca. 60%). Both flights showed peak cylinder head temperatures ranging from about 290-305 deg. F. in cruise (depending on the cylinder). The peak for the hottest cylinder (#4) was at 310 deg. F. during the last ca. 5 minutes of the climb and during a couple of leaning tests. The other cylinders were at the time were at 288, 300, and 304 deg. F at those points. EGT's were between 1320 and 1375 in cruise and peaked at 1340-1420 during a leaning test.

Is there anything here that should trigger a HI CHT alert? If not, what could have triggered it?

By the way, these values are consistent with what I used to see on the single cylinder CHT/EGT gauge installed on cylinder #4 a few owners ago (so I don't think it is an issue with the new installation or instrument).

Thanks for the help. Barry
 
bkspero said:
Finally seem to have gottem most of the kinks out of a new EI CGR-30P engine analyzer and decided to try out the free version of Mike Busch's SavvyAnalysis.com performance analysis tool. There is an "Alerts" column on the My Flights page (where the file names are listed), and both of my flights, with peak cylinder temperatures of about 310 deg. F., showed up with a "HI CHT" alert. I thought that CHT's in this range were on the low end of normal. What am I missing?

Here are more details. I flew the two uploaded flights at relatively low power levels ( ca. 60%). Both flights showed peak cylinder head temperatures ranging from about 290-305 deg. F. in cruise (depending on the cylinder). The peak for the hottest cylinder (#4) was at 310 deg. F. during the last ca. 5 minutes of the climb and during a couple of leaning tests. The other cylinders were at the time were at 288, 300, and 304 deg. F at those points. EGT's were between 1320 and 1375 in cruise and peaked at 1340-1420 during a leaning test.

Is there anything here that should trigger a HI CHT alert? If not, what could have triggered it?

By the way, these values are consistent with what I used to see on the single cylinder CHT/EGT gauge installed on cylinder #4 a few owners ago (so I don't think it is an issue with the new installation or instrument).

Thanks for the help. Barry
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What airplane and what engine?
 
Did you program the alert light off point for that n your POH for the Yellow Line?
 
Henning said:
Did you program the alert light off point for that n your POH for the Yellow Line?
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EI would only program a red line for CHT and only at 500F. POH does not mention CHT. Lycoming O360 manual is the source of their 500F redline.

Don't think alert was in the log file. Came from savvyanalysis.
 
bkspero said:
EI would only program a red line for CHT and only at 500F. POH does not mention CHT. Lycoming O360 manual is the source of their 500F redline.

Don't think alert was in the log file. Came from savvyanalysis.
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Doen't really make sense to me because I wouldn't consider it high at all. Maybe spread?
 
Seems like no one has an explanation for the HI CHT alert. I guess my options are to pay them $130 to correspond with a human at SavvyAnalysis.com, or treat it as the false alarm it seems to be.
 
bkspero said:
Seems like no one has an explanation for the HI CHT alert. I guess my options are to pay them $130 to correspond with a human at SavvyAnalysis.com, or treat it as the false alarm it seems to be.
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I'd assume a programming error. Rule of thumb we use is to keep CHTs under 400...a good buffer below the 500 max. If we see 380+ we look for ways to add some cooling...either cowl flaps or fuel.
 
The Lycoming manual I read recommended keeping CHT's below 400 with yellow line at 450 and red line at 500. I have a CGR-30P on order. These were the numbers I specified on my paperwork for EI to program my monitor. How do you like the CGR-30P? Mine should arrive some time this week. My engine is out for major overhaul and the CGR-30P will be installed on engine reinstallation.
 
Sounds like someone didn't know how to program the alert correctly on the CHT gauge. You can set it for anything. Would you be asking if it was hi if someone set it for 150°F? GIGO.
 
MickYoumans said:
The Lycoming manual I read recommended keeping CHT's below 400 with yellow line at 450 and red line at 500. I have a CGR-30P on order. These were the numbers I specified on my paperwork for EI to program my monitor.
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I posted incorrectly. I went back and looked at my configuration sheet and it is;
150 to 435 Green
435 to 500 Yellow
> 500 Red
 
Make your savvy analysis charts visible to the world (that's an option with that site).

Then post the link to them here.

We'll comment on them for nothing. Which might be exactly how valuable our comments are, but at least we'll enjoy disagreeing, or maybe coming to a consensus.

Be aware that we will be able to see the routes you flew, so don't post your trips to visit someplace you want us to see.
 
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bkspero said:
Seems like no one has an explanation for the HI CHT alert. I guess my options are to pay them $130 to correspond with a human at SavvyAnalysis.com, or treat it as the false alarm it seems to be.
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The alert comes from your programming of the engine monitor. Read the install/setup instructions for the alarms section and you should find your answer. The Saavy Analysis program does not set any alerts that I know of.
 
bkspero said:
EI would only program a red line for CHT and only at 500F. POH does not mention CHT. Lycoming O360 manual is the source of their 500F redline.

Don't think alert was in the log file. Came from savvyanalysis.
Click to expand...

Lycoming's 500F is not only redline but probably total destruction. If you don't have a copy of Lycoming's Key Operations Publication go get it and read it over and over. The recommended limits are well below 450F. In fact keeping temps no higher than 400 in cruise is highly recommended. You will see higher temps in hot weather and on takeoffs.

http://djholman.csde.washington.edu/Yankee/Lycoming/LycomingKeyReprints.pdf

http://www.4shared.com/office/o4sO2J03/Lycoming_Flyer_-_Key_Operation.html?locale=en
 
MickYoumans said:
The Lycoming manual I read recommended keeping CHT's below 400 with yellow line at 450 and red line at 500. I have a CGR-30P on order. These were the numbers I specified on my paperwork for EI to program my monitor. How do you like the CGR-30P? Mine should arrive some time this week. My engine is out for major overhaul and the CGR-30P will be installed on engine reinstallation.
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As you did, I asked for a yellow range for CHT. In my case to start at 430F. Then red at 500F. Both were based on guidance from the O-360 manual from Lycoming. When the CGR-30P arrived, CHT was only programmed with the 500F redline and no yellow line. Similarly, I had listed AMPS as my 4th primary instrument with a yellow range for negative amps. To do this I requested vacuum as secondary on the CGR30P with the intention of leaving in my mechanical vacuum gauge and knowing that I already have vacuum warning annunciation from my standby vacuum system. I had also requested a particular order of the primary readouts to correspond with the order they were placed in the original panel gauges (that were removed).

When it arrived all these were changed. And despite their promise to call before making any changes, there had been no communication from EI. They only programmed the 500F CHT redline, they made Vacuum primary and AMPS secondary, and they ignored my ordering request for the display of the other gauges. In addition, they programmed a wrong lower fuel pressure redline.

When I questioned the changes they explained that their DER required them to be programmed as they did (except for the fuel pressure error). He will not allow vacuum to be secondary. He says that they have to standardize on the order of primary instrument display. And that Lycoming's guidance regarding 400-430F operation is only advisory and that only the 500F redline a requirement.

They sent me new configuration files to correct the fuel pressure error, and none of the other things are a big deal for me. So I'm ok with the changes. But when yours arrives I suggest you carefully review the configuration printout that they provide to confirm what is actually programmed.

When you get yours, could you PM me and let me know how the CHT scale is programmed?

As for operation of the unit, it is striking how much information is packed into a single 3 inch hole. Part of that is having information on 3 different screens, and for that to work they do a very good job of annunciating key information from non-displaying screens in a clear manner on whichever screen is displayed.
 
EdFred said:
Sounds like someone didn't know how to program the alert correctly on the CHT gauge. You can set it for anything. Would you be asking if it was hi if someone set it for 150°F? GIGO.
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See the reply below. Problem solved. A single erroneous high reading buried in each log file was the cause.
 
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Cruiser said:
The alert comes from your programming of the engine monitor. Read the install/setup instructions for the alarms section and you should find your answer. The Saavy Analysis program does not set any alerts that I know of.
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Thanks for the response familiar with how the SavvyAnalysis site operates. It forced me to look more closely at the logfile. A few thousand lines down in the file there is a single reading of 8514F. It doesn't show up in any of the graphs (presumably because there are more data points than there are pixels to display the data). But its there. That's what probably triggered the website to show the alert.

That's the answer.
 
murphey said:
Lycoming's 500F is not only redline but probably total destruction. If you don't have a copy of Lycoming's Key Operations Publication go get it and read it over and over. The recommended limits are well below 450F. In fact keeping temps no higher than 400 in cruise is highly recommended. You will see higher temps in hot weather and on takeoffs.

http://djholman.csde.washington.edu/Yankee/Lycoming/LycomingKeyReprints.pdf

http://www.4shared.com/office/o4sO2J03/Lycoming_Flyer_-_Key_Operation.html?locale=en
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Thanks for the links. The guidance seems like the same as in the O-360 manual. I will read through the documents for anything new.

Thanks again.
 
NoHeat said:
Make your savvy analysis charts visible to the world (that's an option with that site).

Then post the link to them here.

We'll comment on them for nothing. Which might be exactly how valuable our comments are, but at least we'll enjoy disagreeing, or maybe coming to a consensus.

Be aware that we will be able to see the routes you flew, so don't post your trips to visit someplace you want us to see.
Click to expand...

Better to keep the full files private. Here's a CHT/EGT graph for anyone interested.
 

Attachments

  • EGT CHT.pdf
    287.1 KB · Views: 20
What are the black curved arrows indicating?
 
you should be able to program the alert limits yourself. claasic case of needing to read the manual, I guess. don't know anything about EI, have the JPI 730 installed in the cherokee. and the default limits are very reasonable.
 
It would be horribly high with a Rotax, about where you'd like it with a Continental, and unusually low in a Lycoming.
 
kinda skimmed through the previous posts, so I apologize if someone said it already. They recommend staying under 380F in my mooney's lycoming O-360.
 
murphey said:
you should be able to program the alert limits yourself. claasic case of needing to read the manual, I guess. don't know anything about EI, have the JPI 730 installed in the cherokee. and the default limits are very reasonable.
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That part of the programming requires a system password above the level of the user password. I tried to get them to add the yellow range starting at 430, but they wouldn't budge.

Not such a big deal in reality. The display is in my sight line and it is pretty easy to both recognize when the bar height is increasing and see the displayed temperature values.
 
bkspero said:
That part of the programming requires a system password above the level of the user password. I tried to get them to add the yellow range starting at 430, but they wouldn't budge.

Not such a big deal in reality. The display is in my sight line and it is pretty easy to both recognize when the bar height is increasing and see the displayed temperature values.
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send it back, tell them it's for an experimental, and you need it setup like X :)
 
Ron Levy said:
Fabulously low for an O-360-A4K in a Tiger. Lucky you. Don't change a thing other than your high CHT alarm setting, which most Tiger owners set in the 430-450F range.
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I was only running about 55-60% power in level flight...at least that is my estimate based on 2300 rpm at 3500 ft with a Sensenich prop that the logs say is 63 pitch.
 
My tiger chts generally run 350-380
 
jesse said:
send it back, tell them it's for an experimental, and you need it setup like X :)
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Too late for that. Maybe I can just draw a yellow line on the face of the screen with a fine point sharpie<G>.
 
bkspero said:
I was only running about 55-60% power in level flight...at least that is my estimate based on 2300 rpm at 3500 ft with a Sensenich prop that the logs say is 63 pitch.
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Sounds about right on the power percentage, but 310F is still nicely cool for a Tiger.
 
bkspero said:
Too late for that. Maybe I can just draw a yellow line on the face of the screen with a fine point sharpie<G>.
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use a yellow grease pen. easier to see, easier to erase, easier to re-draw.
 
bkspero said:
That part of the programming requires a system password above the level of the user password. I tried to get them to add the yellow range starting at 430, but they wouldn't budge.



Not such a big deal in reality. The display is in my sight line and it is pretty easy to both recognize when the bar height is increasing and see the displayed temperature values.
Click to expand...


Since the EI is a primary instrument replacement gauge, were you able to confirm all of the other parameters were set correctly? They are required to set the parameters to what is in the POH. Since there may be slight changes in the POH of planes from the same make/model, I would check the rest are correct.
 
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