High CHT, 470 degrees +.

[ragedracer1977]

6 hours ago, MikeOH said:

Do you know you had the issue BEFORE the new mag? How about BEFORE the Surefly?

When you say the timing was checked at 25 degrees, that was only for the mechanical mag, correct?

I'm just suspicious of the electronic mag.  Take a flight, get the #4 CHT temp up and then kill the Surefly mag...see if the CHT drops.  That would at least eliminate the Surefly as a contributor.  Do the same with the mechanical mag.

Yes. The issue existed before the new Bendix and Surefly. 

I did what you're suggesting.  

Bendix mag only:

#1-314 #2-345 #3-367 #4-395

Surefly only

#1-342 #2-374 #3-396 #4-433

Looks like they all went up about 30 degrees. That seems to be expected behavior as the surefly advances timing at higher altitudes. 

 

[ragedracer1977]

6 hours ago, carusoam said:

Brice do you have other flights you can share?

The one we are looking at has a few extra variable tossed into the mix...

The FF/MP is getting bumped around a bit... so the EGTs will change each time with that... mixture changes will also affect the data...

It looks as if the flight we are looking at really changed the air/fuel going to each cylinder...

As in EGT1 goes from hottest to coldest after your inflight mag check... red line...

At 6:30... the throttle is opened up... and all four cylinders do something different... one goes straight up, one doesn’t show a change of EGT at all, the other two take an average approach... and one of them shows a delay before rising...

4&3 rise with the power being added... 

EGT1 looks like nothing changed...

EGT2 looks like it waited a minute to fully react...

When talking to your mechanic... focusing a minute on that first full power run may show something interesting... there may be something blocking airflow in front of the carb, of the carb heat misbehaving, or something unexpected...

Comparing to other flight data would be helpful to see if this is a one time event or if every take-off has a bit of wacky power related to it...

PP thoughts only, so... don’t get nervous... yet.  

Best regards,

-a-

 

 

This is the only flight I have data for.  I just installed it lol.  

It looks like I need some better sampling.  Any suggestions on what specifically I should do, and for how long, to get useful data?

[orionflt]

Brice,

first thing I see from this is the 191 on the oil temp, is that only in climb or do you get that in cruise also? Yes I know its not that high in the scheme of things, but in this case we are looking for the small things to figure out what is going on. since yours is a 63' you should still have the doghouse, what are your cruise CHT's? the ones you have posted tell me your doghouse is not as tight as you think and there is a lot of air bypassing. when I redid mine a few years ago my CHTs were around where yours are, my hot cylinder was number 3. now I worry that my cylinders are actually running too cold in the winter. my climb temps may hit 380, my cruise temps are in the high 200, low 300. there are a lot of little places for the air to bypass reducing the cooling. also look over #4 cylinder to ensure the cooling fins are not being blocked. an old birds or mouse nest that has filled some of the cooling fins will really mess up the cooling on that cylinder.

if you have the doghouse off, take pictures from the top looking down and post them, we may be able to see something from them. 

Brian

[ragedracer1977]

40 minutes ago, orionflt said:

Brice,

first thing I see from this is the 191 on the oil temp, is that only in climb or do you get that in cruise also? Yes I know its not that high in the scheme of things, but in this case we are looking for the small things to figure out what is going on. since yours is a 63' you should still have the doghouse, what are your cruise CHT's? the ones you have posted tell me your doghouse is not as tight as you think and there is a lot of air bypassing. when I redid mine a few years ago my CHTs were around where yours are, my hot cylinder was number 3. now I worry that my cylinders are actually running too cold in the winter. my climb temps may hit 380, my cruise temps are in the high 200, low 300. there are a lot of little places for the air to bypass reducing the cooling. also look over #4 cylinder to ensure the cooling fins are not being blocked. an old birds or mouse nest that has filled some of the cooling fins will really mess up the cooling on that cylinder.

if you have the doghouse off, take pictures from the top looking down and post them, we may be able to see something from them. 

Brian

190 has been my oil temp for years.  Rock steady there.  I've always been very pleased with that, since Lycoming suggests 185-210.  

I'll take some pictures.  There isn't any place where even light gets through, except where it's supposed to.

EricJ did point out that there are supposed to be intercylinder baffles.  I'm not sure I have those, but if I don't I never have.

[gsxrpilot]

I might have missed this somewhere but is your sampling rate set to 1 or 2 seconds on the JPI? The default is 6 seconds which is worthless for troubleshooting anything.

[Andy95W]

I'm with Brian.  The extreme #4 CHT really only occurs at what appears to be the climb phase.  Cruise temps all seem pretty uniform.  Low airspeed causing high CHTs is nearly always baffling.

The worst baffling problems I've seen are around the generator, starter, and oil pressure relief valve housing (back behind #3).  Following those three, it's down to the seal that mates the lower dog house to the lower cowling and the thick felt pad that mates the dog house to the upper rear case of the engine.  Of course that assumes the actual dog house sheet metal is all in good shape, which it sounds like yours is.

[0TreeLemur]

9 minutes ago, Andy95W said:

I'm with Brian.  The extreme #4 CHT really only occurs at what appears to be the climb phase.  Cruise temps all seem pretty uniform.  Low airspeed causing high CHTs is nearly always baffling.

The worst baffling problems I've seen are around the generator, starter, and oil pressure relief valve housing (back behind #3).  Following those three, it's down to the seal that mates the lower dog house to the lower cowling and the thick felt pad that mates the dog house to the upper rear case of the engine.  Of course that assumes the actual dog house sheet metal is all in good shape, which it sounds like yours is.

I have the same engine.  My #4 CHT rarely exceeds 410F, and I try to keep it below that number.   Here's a recent flight of mine for reference.  Your graph suggests to me that cooling air flow is the problem.   Just a PPSEL, not an A&P.  Good luck.

 

[ragedracer1977]

26 minutes ago, gsxrpilot said:

I might have missed this somewhere but is your sampling rate set to 1 or 2 seconds on the JPI? The default is 6 seconds which is worthless for troubleshooting anything.

6. But I'll adjust that.  I didn't read the savvy suggestions close enough

[ragedracer1977]

Ill be happy to pay for a savvy analysis as well, but I want to make sure I'm collecting the right data.  

Is there a suggested flight profile or anything?

[gsxrpilot]

14 minutes ago, ragedracer1977 said:

6. But I'll adjust that.  I didn't read the savvy suggestions close enough

This will make running the GAMI spread test much more accurate/useful. Obviously you don't have GAMI's or any injectors. But knowing accurately where each EGT peaks per fuel flow and in what order they peak, could confirm or debunk the theory that #4 is running too lean.

[N205S]

@ragedracer1977 I haven't read through the remainder of the thread but I suggest looking through your JPI manual for troubleshooting procedures. Last week, I saw a 500+ CHT on Cylinder #3 immediately after departure with normal EGT reading. I circled around, landed, and had my mechanic look at it that afternoon. My JPI manual showed a scenario for "CHT more than 500, EGT normal, Adjacent EGT may be low". Probable Cause: Leaking exhaust gasket blowing on CHT Probe. Once we got the cowling off, this was the exact issue. I lock washer wasn't installed where it should have been and the hot air was blowing on the CHT Probe. Quick fix by my mechanic due to the recommendations in the JPI manual. I hope this helps.

[Oldguy]

4 minutes ago, ragedracer1977 said:

Ill be happy to pay for a savvy analysis as well, but I want to make sure I'm collecting the right data.  

Is there a suggested flight profile or anything?

Brice, from your first post, it looks like you are running the Savvy tests they use for analysis. Get up to altitude so you max out at about 65% at WOT, and you should be able to run everything exactly as they specify. If you adjust the sampling to the fastest rate, the only suggestion I have would be to have someone fly with you as a safety pilot so you can focus on doing everything exactly like they would like to have it done for an analysis run. I have found it easier to not have to worry about traffic or letting something slip when I run the tests by taking another pilot with me.

[N201MKTurbo]

What is your idle MP and RPM?

[N201MKTurbo]

Are you sure you don't have your inter-cylinder baffles? I can't believe I would have missed that?

If you are missing them, I rescued a pair of brand new ones from Chuck Esterguard's storage unit after he died. He used to own the engine shop at KCHD and all these engine parts were heading for the dumpster. Mostly junk...

[ragedracer1977]

11 minutes ago, N201MKTurbo said:

Are you sure you don't have your inter-cylinder baffles? I can't believe I would have missed that?

If you are missing them, I rescued a pair of brand new ones from Chuck Esterguard's storage unit after he died. He used to own the engine shop at KCHD and all these engine parts were heading for the dumpster. Mostly junk...

I don't know. Eric and I were talking about it and I can't say one way or the other.  We didn't really look

[Oscar Avalle]

Dear Brice,

Let me tell you that I share your pain. My M20C (SN 700006) with an engine O-360-A1D has been a pain in the behind. I have been struggling with the same issue for years. On a hot day on take off my CHTs in particular number 3, reached easily 475 if I did not manage the climb well. If you search on Mooneyspace you will find a discussion I started around the issue. What did I do:

a) Baffling: I have now the best baffling that a M20C can have. It had a good impact and reduced my CHT3 by 15 degrees. 

b) cowling: I installed a new cowling with a smaller air intake... Marginal impact, but the plane looks much cooler

c) Fuel Flow: my fuel flow was on the lower side (15.6 to 16 gal/hour) on take off. Check you hoses to make sure that there is not obstruction and that you have the right fuel lines. I had one that was too narrow. It increased the fuel flow by 0.5. But then I read something about carburetors and that some Mooneys had a different set of carburetors. I checked if I had the right carburetor. I did, but the fuel flow was not right. So I send it out and it seems that during the overhaul it had been adjusted to the specs of the wrong one... So I asked to overhaul it again. The new flow is now 16,5 to 17 and it makes a HUGE difference. My CHT3 is now down to 420 to 430 on take off on a HOT day. Still high, but not crazy high as before. So look into that option. 

d) Technic: I checked with Savvyanalysis (happy to share the emails with you if you want send me you email through PM). Take off let the plane accelerate to 120 mph and only then climb. Adjust throttle a bit and reduce RPM to 2550 for climb. It helped marginally.

e) Timing: I checked the timing of the ignition, as it was ok, it did not impact my case, but I know for sure that this can be a factor

f) There are more serious issues related to the crankshaft... but just look into that as a last option... I didn't. 

hope it helps

Oscar

[orionflt]

4 hours ago, ragedracer1977 said:

190 has been my oil temp for years.  Rock steady there.  I've always been very pleased with that, since Lycoming suggests 185-210.  

I'll take some pictures.  There isn't any place where even light gets through, except where it's supposed to.

EricJ did point out that there are supposed to be intercylinder baffles.  I'm not sure I have those, but if I don't I never have.

if they are missing, then that is your problem. i was wondering the same thing. your oil temp range should be 100-225 deg F with a redline of 245, 190 is not a bad temp but the vernitherm should be trying to regulate 180 deg F. With your CHT's running where they are it makes sense that your oil temps are going to run hotter.

one other thing to look at is your cowl flap to ensure they are properly adjusted. as you probably already know the upper part of the engine compartment is a high pressure area, the lower section is low pressure. the cowl flaps should be open aprox 1" when closed to give the proper air flow out of the lower cowling. if it is closed up too much or you have ram air coming into the lower cowl the pressure is increased affecting the airflow and ultimately the engine cooling.

Brian 

[carusoam]

3 hours ago, N205S said:

Probable Cause: Leaking exhaust gasket blowing on CHT Probe. Once we got the cowling off, this was the exact issue. I lock washer wasn't installed where it should have been and the hot air was blowing on the CHT Probe. Quick fix by my mechanic due to the recommendations in the JPI manual. I hope this helps.

205S,

thoughts for a CO monitor will follow... 

If you have one, did you get alerted about the exhaust leak?

Best regards,

-a-

[chriscalandro]

Fuel caps

[Andy95W]

Just now, chriscalandro said:

Fuel caps

Definitely funny! 

(But still wish you’d post the successful resolution of your problem for the benefit of everyone here.)

[carusoam]

 Something interesting going on with the Gami spread numbers...

Collecting Gami spread numbers may be challenging the first couple of times...

 

Proper Gami spread data is a FF number each time a cylinder peaks while leaning...

Each cylinder gets a FF number...  most -  least FF gives the overall spread...

a 0.5gph spread is middle of the road... well balanced air intakes mated to well balanced injectors can get the Gami down to 0.1 or 0.0...

1gph is a typical wide spread...

 

In Brices case...

#3 FF 10.3gph            1446 EGT rise 156f

#1 FF 8.7gph              1419 EGT rise 229f

#2 FF 8.5gph              1438 EGT rise 315f

#4 FF 8.5gph              1427 EGT rise 270f

Least is 8.5gph

Most is 10.3gph

#3 is standing out in the crowd...

It is peaking earlier than the other three by a big change in FF

 

If this were a fuel injected engine, the injector in #3 would be pulled and inspected...probably get cleaned and have Black things caught on a paper towel...

How this gets handled with a carburetor takes on a different  method...

 

You may want to start by duplicating the Gami spread test to make sure it was collected properly, repeatability is key...

Why is cylinder #3 peaking first?

When we are looking at cylinder #4 as being the hot one...?

 

Definitely time to collect some more data...

Set the fasted data rate possible... you won’t run out of memory for years... and savvy is a great place to keep the extra data...

Use a lot of time during the run-up... an engine is an analog mechanical device... allow it to stabilize with each click of the ignition switch... watch the EGT graphs rise until they stop... and then decline until they stop again... No rush, the data just gets lost otherwise...

If the JPI data selection was 6 seconds... it is possible the peak didn’t actually get collected... it might be a single point of data if the ignition switch was twisted based on what the pilot was hearing and seeing on the tach...

The tach reacts really quickly, but we are looking at EGTs which may take more time to change, over 10-15 seconds...

PP thoughts only, not a mechanic...  

making headway...

Best regards,

-a-

 

 

[ragedracer1977]

I'm getting ready to go fly now.  I'm going to take a lot more time for each test iteration.  

Here some photos of the dog house.  It was basically dark in the hangar with a very bright LED shop light in the cowl.  As far as I can see the only light is coming through very small areas such as an old screw hole and the pass through mounts for the plug wires.

At the front of cylinder 2, there's a little light, but I can't see how you could make that better.

I also tried to take pictures looking down through the fins.  I can't see any obstructions at all. 

Last is a photo of the probe area.  Do you see any signs of exhaust blowing on it?

[Andy95W]

Looks good, Brice, but it looks like you might be missing the inter-cylinder baffling between your #2 and #4 cylinders.  It's difficult to tell based on your photo looking down.

The photo below shows a different Lycoming engine, from underneath the cylinder.  The O-360 baffle is smaller.

 

EDIT- this is the parts manual for the O-360.  Ours are quite a bit smaller.

[carusoam]

Sometimes the piece of sheet metal that goes in there looks different...

But something has to go in there to block air from escaping between the gap between cylinders...

The amount of air going through there must be just a small breeze... so any interruption or rerouting of air will be significant...

Best regards,

-a-

[Andy95W]

Your baffling really does look pretty good.  If you'd like, here are two ideas to seal up in front of #2 a little better.