Would you look further?

[NJMac]

For the last year that I've been flying my E, cylinder number 3 was always my hottest and would peak around 1350 running 150 degrees Rich of peak about 12 gph fuel flow.

 

The last two or three flights number two has been the hottest cylinder. previous two flights I was able to lean it out to around the same fuel flow roughly 12 gallons an hour as before but cylinder number two was peaking first at 1350.

 

Tonight the plane was effectively full rich and running at 1350. Would this situation I described give anyone reason to look further or doubt the health of the engine currently?

 

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[carusoam]

You are always going to be looking for something....

 

Absolute EGT numbers require an understanding of where the probes are mounted compared to one another...

1) The older the plane, the less likely they were mounted with the required precision to be comparable.... mm(s) actually matter in this case...

EGTs are dropping quickly as the gasses expand down the pipes...  MS thermo at work...

This is why we use Gami spreads for comparing EGTs... Pk4’s FF - Pk1’s FF...  isn’t thermo a blast? 

 

2) Then, we want to know about spark plugs in that cylinder.... a failing plug is similar to running on one mag... the EGT automatically rises as more and more fuel is escaping the cylinder before burning... burning right where the EGT sensor is...

Be on the look-out for high resistance plugs by a company called...

 

3) Where is the fifth EGT sensor mounted? Is this related to your odd EGT? Where is the ship’s EGT mounted?

 

4) a really high CHT May match with a high EGT... But now more variables are coming into play... hey, your CHTs are pretty close... wanna stop here? (Of course you don’t)...

5) Time to test those JPI skills... load some JPI data into Savvy include some fun things like a well orchestrated run-up... and an inflight mag check... then we can see some things worth looking at...

 

6) Doesn’t that fancy JPI do a Gami spread analysis automatically..? It’s powerful enough, it should...  If nothing else... the graphs of EGT v. Time and FF v. time can be used to determine the Gami... just lean slowly enough near the peaks to allow for some good data acquisition... set the JPI to collect data every second if possible...

 

PP thoughts that come to mind... not a mechanic...

Best regards,

-a-

[Ragsf15e]

Could be all kinds of things, because absolute egt numbers are relatively meaningless like Carusaum said... that being said, it seems odd... have the chts remained about the same?  Is it generating the same power?  Climb/airspeed?

[Two Oh One]

In messing around with my EDM900, I've learned the value in making true apples to apples comparisons. Are these numbers all taken at the same density altitude, throttle angles, etc?

[ArtVandelay]

Ignore absolute temperatures, when you do LOP, what was and now is the order of cylinders peaking and at what is the fuel flow when they peak?


Tom

[NJMac]

You are always going to be looking for something....
 
Absolute EGT numbers require an understanding of where the probes are mounted compared to one another...
1) The older the plane, the less likely they were mounted with the required precision to be comparable.... mm(s) actually matter in this case...
EGTs are dropping quickly as the gasses expand down the pipes...  MS thermo at work...
This is why we use Gami spreads for comparing EGTs... Pk4’s FF - Pk1’s FF...  isn’t thermo a blast? 
 
2) Then, we want to know about spark plugs in that cylinder.... a failing plug is similar to running on one mag... the EGT automatically rises as more and more fuel is escaping the cylinder before burning... burning right where the EGT sensor is...
Be on the look-out for high resistance plugs by a company called...
 
3) Where is the fifth EGT sensor mounted? Is this related to your odd EGT? Where is the ship’s EGT mounted?
 
4) a really high CHT May match with a high EGT... But now more variables are coming into play... hey, your CHTs are pretty close... wanna stop here? (Of course you don’t)...
5) Time to test those JPI skills... load some JPI data into Savvy include some fun things like a well orchestrated run-up... and an inflight mag check... then we can see some things worth looking at...
 
6) Doesn’t that fancy JPI do a Gami spread analysis automatically..? It’s powerful enough, it should...  If nothing else... the graphs of EGT v. Time and FF v. time can be used to determine the Gami... just lean slowly enough near the peaks to allow for some good data acquisition... set the JPI to collect data every second if possible...
 
PP thoughts that come to mind... not a mechanic...

Best regards,
-a-

Honestly can't answer many of those questions. My concern stemmed from the abrupt change that was most noticeable last night.

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[NJMac]

... that being said, it seems odd... have the chts remained about the same?  Is it generating the same power?  Climb/airspeed?

Yes, CHTs have been similar. If anything its making more power. Dense cool air recently but it's been climbing like a boss, as good if not better than ever and airspeed is as good if not a hair better than before.

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[NJMac]

Are these numbers all taken at the same density altitude, throttle angles, etc?

Yes, i dont mess with fuel flow until I'm straight and level, set cruise power, closed flaps. That's when I start watching temps as I lean to 150 ROP down low or 50 LOP up high.

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[NJMac]

Ignore absolute temperatures, when you do LOP, what was and now is the order of cylinders peaking and at what is the fuel flow when they peak?


Tom

I went back thru my photos of past flights and grabbed these JPI shots. Does this help with any insight?

I did sign up for savvy engine analysis thus morning. Wondering if they will see any trends

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[orionflt]

look under the cowl at the fuel injectors, see if there is any blue staining on any of them. injectors may need to be cleaned.

Brian

[Marauder]

You might be looking for a problem that doesn't exist. Since I bought my plane F 28 years ago, I have always had an engine analyzer in it. All of my cylinders at one time or another have peaked before the others. EGTs also will vary depending on OAT, altitude, heck even barometric pressure. What I do look for is a seriously off indication, not the normal variability I will see from flight to flight.

I will find and post a few examples.

[Marauder]

Last week.



A few weeks before during a final climb to altitude.



Some older ones at cruise.







This one is a little hard to see but the EGT for #2 is much warmer than 3.




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[NJMac]

You might be looking for a problem that doesn't exist. Since I bought my plane F 28 years ago, I have always had an engine analyzer in it. All of my cylinders at one time or another have peaked before the others. EGTs also will vary depending on OAT, altitude, heck even barometric pressure. What I do look for is a seriously off indication, not the normal variability I will see from flight to flight.
I will find and post a few examples.

Have you ever had an issue where you were at peak temp and not able to lean the mixture? Appreciate the pics and feedback so far

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[ArtVandelay]

I went back thru my photos of past flights and grabbed these JPI shots. Does this help with any insight?

Not really, but just looking at you OAT range -7 to 25 tells me you really can’t compare different flights.

You need to go up, lean the engine from rich to lean...slowly, then upload data to savvy. Use their gami find functionality to get your fuel flow spread.


Tom

[Oldguy]

3 hours ago, NJMac said:

I did sign up for savvy engine analysis thus morning. Wondering if they will see any trends

Go to the Savvyanalysis.com site and read their Flight Test Profiles section under the Learn More tab. Follow their instructions and send the resulting data file in with a request to have it analyzed by them. I have found it usually takes less than 24 hours to get a response back from them with all kinds of good information.

The profile they have you fly stresses several systems in your engine and helps identify where problems are occurring or likely to occur, and the resulting report is very specific.

[KLRDMD]

13 hours ago, NJMac said:

For the last year that I've been flying my E, cylinder number 3 was always my hottest and would peak around 1350 running 150 degrees Rich of peak about 12 gph fuel flow.

The engine monitor shows 13.5 GPH. For a 200 HP normally aspirated engine that's a tremendous fuel flow. I cruise at 12.5 GPH with a 285 HP engine.

[NJMac]

The engine monitor shows 13.5 GPH. For a 200 HP normally aspirated engine that's a tremendous fuel flow. I cruise at 12.5 GPH with a 285 HP engine.

LOP? Most of my flights are short hops down low and i shoot for 150 ROP.

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[Oldguy]

1 minute ago, NJMac said:

LOP? Most of my flights are short hops down low and i shoot for 150 ROP.

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What does your POH show for for fuel flow for Best Power (kind of ROP ) and Best Economy (kind of LOP) at the altitudes and power level you fly? I know mine has a statement in the Normal Operating Procedures about not letting the CHTs get below 300 dF during a descent, but most of yours in the photos are not even that high at what looks to be level cruise.

[NJMac]

What does your POH show for for fuel flow for Best Power (kind of ROP ) and Best Economy (kind of LOP) at the altitudes and power level you fly? I know mine has a statement in the Normal Operating Procedures about not letting the CHTs get below 300 dF during a descent, but most of yours in the photos are not even that high at what looks to be level cruise.

I can't say from top of mind. You're right my CHTs have always been very low.

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[jaylw314]

11 minutes ago, NJMac said:

LOP? Most of my flights are short hops down low and i shoot for 150 ROP.

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My POH for an IO-360 in an M20J shows a fuel flow of 10.5 or 10.8 gph for 24/2400 or 23/2500 at best power (125^oF ROP).  I can't imagine your numbers are terribly different?

Edit: Oh, never mind, I saw in your OP that you were full rich in the first image.  One suggestion would be to check the probe is secure in the exhaust riser.  I had one that backed out about 3/4" and threw off my numbers by about 100^oF.  Fortunately, the wire was secured so it couldn't back out completely.

[Oldguy]

1 minute ago, NJMac said:

I can't say from top of mind. You're right my CHTs have always been very low.

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Even where you are running 8.2 and 8.7 gph, you only have 1 CHT above 300 dF.

You must have AWESOME cooling if everything is showing accurately.

Have you matched your fuel usage against fuel pumped into a tank to make sure everything matches up?

I have serious envy of your CHTs....

[NJMac]

Have you matched your fuel usage against fuel pumped into a tank to make sure everything matches up?
I have serious envy of your CHTs....

I haven't watched that closely. I tend to trust and then verify if something draws my attention. I'll start watching now.

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[ArtVandelay]

BTW,

Your 2nd shows 67% HP on 8.2gph, the other shows 70% on 8.7gph.

That’s wrong, it should be 55%, and 60%.

 

Check your MP pressure setting before starting the engine, it should match current atmosphere pressure.

Also check setting for horsepower constant, should be 120 I think.

 

 

Tom

 

[jaylw314]

3 minutes ago, ArtVandelay said:

BTW,
Your 2nd shows 67% HP on 8.2gph
That’s wrong, it should be 55%.

Check your MP pressure setting before starting the engine, it should match current atmosphere pressure.
Also check setting for horsepower constant, should be 120 I think.

I thought JPI's calculate HP solely by MP/RPM, which only works for ROP?  8.2 gph would be LOP for those settings...

[ArtVandelay]

16 minutes ago, jaylw314 said:

I thought JPI's calculate HP solely by MP/RPM, which only works for ROP?  8.2 gph would be LOP for those settings...

If they’re assuming ROP, then it’s even worst.  I was using IO360 power schedule, but didn’t know altitude so just pick 5000-6000’ where I had matching FF. Thats why I said to check HP constant, which is used in JPI formula.