Hot cylinder solutions needed

[jetdriven]

C models with the doghouse run hot on takeoff. They run hot in cruise too. You can re-jet the carb for more fuel flow or you can send your carb to msacarbs and they can open up the main jet. 

[Greg Ellis]

1 hour ago, jetdriven said:

C models with the doghouse run hot on takeoff. They run hot in cruise too. You can re-jet the carb for more fuel flow or you can send your carb to msacarbs and they can open up the main jet. 

I have the rich carb and run 19 gph on take off.  It is just the one cylinder and has repeated itself from the previous cylinder.  Both were new and both had this happen immediately and throughout break in.  The cylinder before these two ran just fine and ran relatively cool in the mid to upper 300's like my other 3 cylinders do.  I don't really think it is a dog house issue or a carb issue since I have three cylinders that run in the mid to upper 300's and barely kiss 400 in climb out in a hot Texas summer and one cylinder that runs 480 on climb out and 430 in cruise on a hot or frigid day. (one day flown last week in the upper 30's.  Frigid for Texas)

[47U]

11 minutes ago, Greg Ellis said:

The cylinder before these two ran just fine and ran relatively cool in the mid to upper 300's like my other 3 cylinders do. 

So, all three cylinders on the same lower end?  Narrow deck or wide deck?

My friends ‘68G wide deck ran hot, albeit chrome cylinders, but over the years he swapped out three of the four to steel and it was better, but still  ran hot.  He was challenged to keep it under 440-450 on climb.  My question is… do wide deck O-360s run hotter than narrow deck O-360s?

[Greg Ellis]

37 minutes ago, 47U said:

So, all three cylinders on the same lower end?  Narrow deck or wide deck?

My friends ‘68G wide deck ran hot, albeit chrome cylinders, but over the years he swapped out three of the four to steel and it was better, but still  ran hot.  He was challenged to keep it under 440-450 on climb.  My question is… do wide deck O-360s run hotter than narrow deck O-360s?

Same lower end.  Narrow deck.

[47U]

28 minutes ago, Greg Ellis said:

Same lower end.  Narrow deck.

I’m curious what the results of the inflight cylinder lean test will be… you’ve already gone through the intake and exhaust for issues.  And the plug swapout.

Otherwise, something in the valve train?  Pushrods/lifters/cam lobes.  The fact that the problem followed after the cylinder change points to what has commonality between the old and new cylinders. 

[Greg Ellis]

Just now, 47U said:

I’m curious what the results of the inflight cylinder lean test will be… you’ve already gone through the intake and exhaust for issues.  And the plug swapout.

Otherwise, something in the valve train?  Pushrods/lifters/cam lobes.  The fact that the problem followed after the cylinder change points to what has commonality between the old and new cylinders. 

The plug swap out will happen this weekend along with other things (flight test, etc).  I will report back my findings.

[Fly Boomer]

19 hours ago, 47U said:

The fact that the problem followed after the cylinder change points to what has commonality between the old and new cylinders.

Or that something was inadvertently changed when swapping cylinders.

[PT20J]

1. You have ample physical evidence that the high temps are real. Use the well probe -- it will be the most accurate.

2. Intake leaks are most noticeable at low power, but if that cylinder is running leaner than the others it should drop out well before the others when leaning aggressively.

3. The rate of the temperature rise on takeoff together with the damage caused to the first cylinder could indicate preignition. Since this happened on two cylinders in the same position, it would have to caused by something you did not change such as the plugs or the magnetos. It's possible one of the plugs has a cracked insulator. When one of the insulators cracked on my engine it would do something similar at high power. I would replace the plugs in that cylinder with new ones.

4. I would borescope the new cylinder to determine if there has been any damage. 

[1967 427]

Just one more thing to check, timing.  If the mags were somehow advanced more than they should be, cylinders WILL run hot.

[N911TP]

We have the same engine. Since you’ve already burned up a cylinder I’d stop doubting your JPI. It doesn’t sound like a probe issue. 
 

Check baffling/dog house. One baffle or misplaced dog house panel can throw your temps off. Don’t lean so early. Consider keeping your fuel pump on longer until cruise. Avoid prolonged taxi. Keep the runup short. Climb out at 120 MPH. I live where it gets 100+ in the summer and my home airport has a 10,000’ runway. I never use full length to avoid overheating. Mooneys are not known for great cooling. This is just a way of life for us… 

Edited Friday at 08:23 AM by N911TP

[Greg Ellis]

Here is a very short flight done today.  I changed out the spark plugs to no avail.  I don't want to fly the airplane for very long running this hot on the #3 cylinder.  I did an induction leak check according to Mike Busch at around the 17 minute mark.  As you can see the only cylinder running hot is the #3 cylinder.

https://apps.savvyaviation.com/flights/shared/flight/10328542/85e6027a-1330-4240-89d3-54b3c6395d9f

[hazek]

Well, you can stop worrying about the CHT probe, nr 3 is clearly running hot. Also about any baffling issues, it’s connected with combustion from the moment you apply a high power setting. It’s interesting how the EGT spread drops when in the descent at descent power.

So either fuel, air or spark is off - and only at high power settings. You checked the spark plugs, what about the ignition harness? Air - seems like there’s no induction leak. Fuel - can something be going wrong here? FF seems normal.

I’m no expert, on the contrary. But this is what I noticed. I hope you get someone knowledgeable to take a look and give you their input. It’s an interesting case, sorry you have to deal with it.

[Slick Nick]

Woah that #3 is getting HOT! Agree about the harness they can be tricky to diagnose but it’s worth a shot. 

[Ragsf15e]

1 hour ago, Slick Nick said:

Woah that #3 is getting HOT! Agree about the harness they can be tricky to diagnose but it’s worth a shot. 

There’s some way to test them i think?

[47U]

3 hours ago, Greg Ellis said:

As you can see the only cylinder running hot is the #3 cylinder.

Was hoping the new plug would help you out… during the airborne lean test, when did the #3 drop out compared to the other cylinders?

Has the #3 intake tube flange been inspected to make sure that it’s absolutely flat?  Did I read once upon a time that someone used two intake gaskets to ensure a good seal?  Can you make sure there’s no damage to the engine side of the intake tube where it enters the sump?

In your Savvy link, at 16:44 the #3 EGT drops… so that was the first cylinder to misfire during the lean test?

Curious what @N201MKTurbo and @PT20J thinks…

[Greg Ellis]

16 minutes ago, 47U said:

Was hoping the new plug would help you out… during the airborne lean test, when did the #3 drop out compared to the other cylinders?

Has the #3 intake tube flange been inspected to make sure that it’s absolutely flat?  Did I read once upon a time that someone used two intake gaskets to ensure a good seal?  Can you make sure there’s no damage to the engine side of the intake tube where it enters the sump?

In your Savvy link, at 16:44 the #3 EGT drops… so that was the first cylinder to misfire during the lean test?

Curious what @N201MKTurbo and @PT20J thinks…

I am going to insepct the intake tubing, the flange, the gaskets, the rubber connector, etc…next weekend.  Just ran out of time this weekend to do much with it.  Thank you for the response.  I will continue to post what is found out as I work on it.

[Greg Ellis]

1 hour ago, Ragsf15e said:

There’s some way to test them i think?

I have an E5A harness tester from Aircraft Tool and Supply.  The leads to the #3 spark plugs tested good according to the tester.

[Ragsf15e]

1 hour ago, Greg Ellis said:

I have an E5A harness tester from Aircraft Tool and Supply.  The leads to the #3 spark plugs tested good according to the tester.

Sheesh, you’ve got to get to the bottom of this mystery as much for us as for you and your airplane!

[Ragsf15e]

1 hour ago, Ragsf15e said:

Sheesh, you’ve got to get to the bottom of this mystery as much for us as for you and your airplane!

Have you or your mechanic put a borescope into the cylinder through the spark plug hole, turned over the engine and watched the valves?  Maybe compare them to #4?

[hazek]

5 hours ago, Greg Ellis said:

I will continue to post what is found out as I work on it.

Have you considered to subscribe to Savvy’s analysis service? When I had a symptom last year they correctly analyzed my data and correctly diagnosed my problem. They’re very good at this. Might be worth the subscription.

[Greg Ellis]

7 hours ago, hazek said:

Have you considered to subscribe to Savvy’s analysis service? When I had a symptom last year they correctly analyzed my data and correctly diagnosed my problem. They’re very good at this. Might be worth the subscription.

I do subscribe and I have submitted the data for analysis.

[Greg Ellis]

9 hours ago, Ragsf15e said:

Have you or your mechanic put a borescope into the cylinder through the spark plug hole, turned over the engine and watched the valves?  Maybe compare them to #4?

Have not done that.  I borescoped it yesterday just to see if there was any damage and everything looked okay.  but did not move it through to look at the movement of the valves.  Thanks for the advice.

[Ragsf15e]

26 minutes ago, Greg Ellis said:

Have not done that.  I borescoped it yesterday just to see if there was any damage and everything looked okay.  but did not move it through to look at the movement of the valves.  Thanks for the advice.

By “turned it over”, I meant pulling the prop through by hand (carefully).  I think you knew that but just wanted to be sure.

[Greg Ellis]

27 minutes ago, Ragsf15e said:

By “turned it over”, I meant pulling the prop through by hand (carefully).  I think you knew that but just wanted to be sure.

Yes sir.  Thanks.