#3 Cylinder runs very hot after overhaul

[Greg Ellis]

I have a 1963 C model.  It has an O-360-A1D engine.  I had a problem at the end of the summer with a broken engine mount and the #3 cylinder needed to be overhauled.  Both intake and exhaust valves were apparently bad.  It took the shop an extremely long time to fix everything.  Most of the problem was the choice of shop I had was on my home airport and I usually do not use them for mechanical issues, only for avionics (they are a very good shop with a good reputation).  But I could not fly the airplane due to the broken motor mount and the #3 cylinder to my usual mechanic.  They told me it would take a long time because they were booked solid through December (started this in August) with annuals.  They are a big shop.

Anyways, I got the airplane back last Saturday.  Everything ran well on the ground, run up was perfect.  The plane actually flew extremely well and very smooth which makes me wonder how long the motor mount had a problem.  The issue is that the #3 cylinder which was over hauled ran very hot on takeoff.  Over 450 degrees according to the JPI!!!  When I brought the power back it cooled off but ran 80 to 90 degrees hotter than the other 3 cylinders.  The other 3 cylinders were in the low 300's and #3 was high 300's to low 400's.  Fuel flow on take off was 18.8 gph according to the JPI.  All other gauges were in the green.

I told the shop about it and they are going to look it over today.  Off the top of their heads they talked about making sure the cowl flaps opened far enough and that the baffling was good and tight.  It is the dog house style baffling and had been replaced about 7 or 8 years ago.  While it was in this shop they said they had to repair an area of the baffling.

Besides those 2 things is there anything else they should be looking at?  I know it is normal for a new cylinder to run hotter during break in but I feel that going over 450 is excessive.  So any ideas of what else it could be if anything?  I do apologize but I did not download the flight from the JPI.  I will do that this weekend when I am back out at the airport.

Thanks.

[ArtVandelay]

First, sanity check the probe by checking it show ambient temperature before you start it.
I had temperatures around 410-420 when I was breaking in my overhauled engine. It took a 2 hour test flight to get them below 400. I kept temperatures under control by running rich. You should be using a break in oil of some kind (no anti scuff additives).

[Greg Ellis]

ArtVandelay….I spoke to the shop.  It is the recommended break in oil that is being used.  I looked at the temp on the probe on Sunday after it had been sitting in the hangar all night and all 4 probes registered the same temp and it was roughly hangar temp of 40 degrees.  Thank you for the response and the ideas.  I am going flying again on Thursday and more this weekend and hopefully will see a difference.  On the first flight after the work was done, I flew it at 2500 feet, full rich and kept the power between 70 and 75% as recommended by Lycoming during break in.  Thanks again.

[Oldguy]

4 hours ago, Greg Ellis said:

While it was in this shop they said they had to repair an area of the baffling.

Probably a good place to review what was done while making sure nothing on the doghouse was left out/off when it was reassembled.

If  you had the injected engine I would suggest looking for induction leaks or the baby jar test, but my assumption is you have the O-360.

Are the EGTs close to even across all cylinders?

[HRM]

Baffling. No, I mean the engine. I had saggy engine mounts to the point that the clearance at the lower cowl was 'just barely'. Replaced the mounts and spaces and Voila! no more overheating. Just need to check everything carefully to make sure all is aligned and no air leaks. At least you know which jug to concentrate on.

Then there's the oops! Like, oops! we forgot to put whatever that springy thing is that goes between the jugs and pulls the lower baffle piece up and tight. Or oops! we left a rag in there.

Oops happens.

[Greg Ellis]

14 minutes ago, Oldguy said:

Probably a good place to review what was done while making sure nothing on the doghouse was left out/off when it was reassembled.

If  you had the injected engine I would suggest looking for induction leaks or the baby jar test, but my assumption is you have the O-360.

Are the EGTs close to even across all cylinders?

The EGT's, if I remember correctly (I forgot to download the JPI data) were fairly even across all cylinders.  Nothing stood out to me.  I did not look at the doghouse because that meant pulling off the cowling which is a pain the you know what in these old C models (about 75 screws to remove).  And it is the O-360-A1D engine.  Thanks for your response.

[Greg Ellis]

Just now, HRM said:

Baffling. No, I mean the engine. I had saggy engine mounts to the point that the clearance at the lower cowl was 'just barely'. Replaced the mounts and spaces and Voila! no more overheating. Just need to check everything carefully to make sure all is aligned and no air leaks. At least you know which jug to concentrate on.

Then there's the oops! Like, oops! we forgot to put whatever that springy thing is that goes between the jugs and pulls the lower baffle piece up and tight. Or oops! we left a rag in there.

Oops happens.

Thanks for the response Harley.  I am going to remove the cowling later this week and double check that all was installed correctly.  My first thought was the "springy thing" because I remember that being quite tight with close tolerances and was important to cooling and mine had to be replaced at one time a while back.  The engine should not be sagging since the motor mount was replaced at the same time the cylinder work was done, new Lord mounts were used and the engine was shimmed according to my bill.  I have not actually read the log book entries yet as to what was entered in them.

[DonMuncy]

First thing I would do is swap the 1 and 3 CHT probes and fly it to see if perhaps the # 1 might now show the high temp. Thus a bad probe. I had it happen on my K model.

[HRM]

30 minutes ago, pmccand said:

Took me three times to get the intake pipe lined up perfectly.  Check it again.

That might qualify as an 'oops!' given that the jug was replaced. Damn easy to check (see the Youtube video here).

[takair]

6 hours ago, Greg Ellis said:

I have a 1963 C model.  It has an O-360-A1D engine.  I had a problem at the end of the summer with a broken engine mount and the #3 cylinder needed to be overhauled.  Both intake and exhaust valves were apparently bad.  It took the shop an extremely long time to fix everything.  Most of the problem was the choice of shop I had was on my home airport and I usually do not use them for mechanical issues, only for avionics (they are a very good shop with a good reputation).  But I could not fly the airplane due to the broken motor mount and the #3 cylinder to my usual mechanic.  They told me it would take a long time because they were booked solid through December (started this in August) with annuals.  They are a big shop.

Anyways, I got the airplane back last Saturday.  Everything ran well on the ground, run up was perfect.  The plane actually flew extremely well and very smooth which makes me wonder how long the motor mount had a problem.  The issue is that the #3 cylinder which was over hauled ran very hot on takeoff.  Over 450 degrees according to the JPI!!!  When I brought the power back it cooled off but ran 80 to 90 degrees hotter than the other 3 cylinders.  The other 3 cylinders were in the low 300's and #3 was high 300's to low 400's.  Fuel flow on take off was 18.8 gph according to the JPI.  All other gauges were in the green.

I told the shop about it and they are going to look it over today.  Off the top of their heads they talked about making sure the cowl flaps opened far enough and that the baffling was good and tight.  It is the dog house style baffling and had been replaced about 7 or 8 years ago.  While it was in this shop they said they had to repair an area of the baffling.

Besides those 2 things is there anything else they should be looking at?  I know it is normal for a new cylinder to run hotter during break in but I feel that going over 450 is excessive.  So any ideas of what else it could be if anything?  I do apologize but I did not download the flight from the JPI.  I will do that this weekend when I am back out at the airport.

Thanks.

Are you aware of the Lycoming recommended break in procedure?  I don’t recall the number at the moment, but it has the best advice for break in. You didn’t really mention speeds and power settings, but power should be high and speeds high, including climb. Following the procedure will get temps down within the two hours, but I agree the 450 seems excessive. 

[Greg Ellis]

Just now, takair said:

Are you aware of the Lycoming recommended break in procedure?  I don’t recall the number at the moment, but it has the best advice for break in. You didn’t really mention speeds and power settings, but power should be high and speeds high, including climb. Following the procedure will get temps down within the two hours, but I agree the 450 seems excessive. 

Yes, I am very familiar with the break in procedure and was running the airplane accordingly. It is Lycoming SI 1427C.  I just finished watching the video by Mike Busch on breaking in an engine and cylinders and he stated that 450 in a Lycoming is not excessive during break in.  Thanks for the response.

[Greg Ellis]

44 minutes ago, DonMuncy said:

First thing I would do is swap the 1 and 3 CHT probes and fly it to see if perhaps the # 1 might now show the high temp. Thus a bad probe. I had it happen on my K model.

Thanks for the response Don.  If all else fails I will start looking into this as well.  According to the Mike Busch video, the temps are not excessive for break in but I will see in another flight and see what happens.  All are great suggestions.

[carusoam]

Expect break-in to show interesting behaviors... may take 10hrs to settle out... or more...

When it happens, the JPI trails will be interesting to see... it can be hot one minute and back to normal the next... depending on what minute It happens...

+1 on giving the doghouse a complete review to make sure everything is in place... most is viewable from the outside.. of the DH... saving a lot of screw removal time...

Unlike engine OH... the cylinders don’t get Any pre-run time... so you get to see virgin square edged rings installed.

Some quirky JPI Numbers can be caused by either loose intake tubes or exhaust pipes... make sure the seals and nuts are in place...

Got a dental camera?  Great time to buy one.  Now you sort of kinda have a reason... 

Some OH'd engines see multiple hours on a test stand before they get installed in a your plane...

Best regards,

-a-

[Greg Ellis]

5 hours ago, carusoam said:

Expect break-in to show interesting behaviors... may take 10hrs to settle out... or more...

When it happens, the JPI trails will be interesting to see... it can be hot one minute and back to normal the next... depending on what minute It happens...

+1 on giving the doghouse a complete review to make sure everything is in place... most is viewable from the outside.. of the DH... saving a lot of screw removal time...

Unlike engine OH... the cylinders don’t get Any pre-run time... so you get to see virgin square edged rings installed.

Some quirky JPI Numbers can be caused by either loose intake tubes or exhaust pipes... make sure the seals and nuts are in place...

Got a dental camera?  Great time to buy one.  Now you sort of kinda have a reason... 

Some OH'd engines see multiple hours on a test stand before they get installed in a your plane...

Best regards,

-a-

Thanks for the response.  I am planning on flying the plane again tomorrow and will give the doghouse a good look to make sure everything is in tact and where it should be.  As far as the dental camera goes, being a dentist , I have 3 or 4 of them and they are very handy outside of my practice.  I also have a borescope if I need one as well.  I am currently making a list of things to check thanks to this wonderful Mooney forum!!!

[Guest]

Make sure that the rubber seal on the lower engine baffles is seated into the groove in the lower cowl.  If your airplane has the dog house upper baffles it too has a rubber seal, check that it is seated in the groove as well.

Clarence

[Greg Ellis]

Just now, M20Doc said:

Make sure that the rubber seal on the lower engine baffles is seated into the groove in the lower cowl.  If your airplane has the dog house upper baffles it too has a rubber seal, check that it is seated in the groove as well.

Clarence

Thanks very much for the response.  I will check on that tomorrow.

[HRM]

1 hour ago, pmccand said:

Actually, No OOPS...not so easy to find.  That’s why it took THREE TIMES to find it.  After 50 years of thermal expansion and contraction, improper fittings of the past, the face of the induction tube flange was warped which could only have been found using the flat plate of a machinists bar and a feeler gauge. Alternatively, one could have used a plate of glass, but for whatever reason, it had a small amount of warpage that could not be detected by the eye, but was large enough that the gasket could not take up the gap.  Again, check your intake tubes for warpage or small dents.

Agreed, THAT is not an oops. That said, if in reinstalling the jug the stack was not tight, THAT's an oops.

[Ragsf15e]

I’m currently breaking in a new cylinder too, but in an io-360.  Mine was noticeably warmer than the others, but nothing like yours.  I’m seeing like 380 in cruise while the others are 330.  I have the bonus of very cold air temperatures for breaking it in (Eastern Washington in winter).

What kind of cylinder is it? Mine is chrome.

so one last thing to possibly just glance at... make sure you don’t have a small exhaust leak on that cylinder or the one next to it heating up the area near the probe.

[tigers2007]

My #3 always runs warmer... I think it is an inherent issues with the oem cooling design.

[Greg Ellis]

On 2/27/2020 at 11:15 AM, Ragsf15e said:

I’m currently breaking in a new cylinder too, but in an io-360.  Mine was noticeably warmer than the others, but nothing like yours.  I’m seeing like 380 in cruise while the others are 330.  I have the bonus of very cold air temperatures for breaking it in (Eastern Washington in winter).

What kind of cylinder is it? Mine is chrome.

so one last thing to possibly just glance at... make sure you don’t have a small exhaust leak on that cylinder or the one next to it heating up the area near the probe.

Mine is a steel cylinder.

[FloridaMan]

Think of taking a hair comb and putting it under the water coming out of your sink. There’s plenty of pressure, but it prefers to go around the teeth unless there’s nowhere else to go. It sounds like this is what’s happening and the air is going around your fins and not through them. Check your baffling. Also check for obstructions preventing air from exiting your lower cowl under that cylinder. 

Edited March 1, 2020 by FloridaMan

[carusoam]

Water has that hydrogen bonding thing that keeps the water pulling together... making it a big blob forced to try and avoid the comb’s teeth...

Air doesn’t have the magical hydrogen atoms...

But... the part about pressure differential is spot on... it takes pressure to push the air down through the fins...

The more pressure the better...

The fewer escape routes the better, as well...

PP thoughts only not a mechanic...

Best regards,

-a-

[HRM]

3 hours ago, FloridaMan said:

Think of taking a hair comb and putting it under the water coming out of your sink. There’s plenty of pressure, but it prefers to go around the teeth unless there’s nowhere else to go. It sounds like this is what’s happening and the air is going around your fins and not through them. Check your baffling. Also check for obstructions preventing air from exiting your lower cowl under that cylinder. 

I think this analogy is spot on. We often forget that air is a fluid.

[Greg Ellis]

I would like to post an update on this issue and see if anyone has any input (please see original post for initial history).  So the #3 cylinder continues to show a very high temperature on the EDM 900.  It hits about 470 at about 1000 feet on take off.  It will cool off in cruise but stays above 400 degrees when all other 3 cylinders are in the mid 300's.  A lot has been done to trouble shoot this since I first posted about it but to no avail.  The probes were swapped, no change. A new probe was put in.  No change.  The wires were checked for shorts and grounding issues, none were found.  They took the #1 and the #3 probes and put them in boiling water and they registered the correct temp on the EDM 900.  They have checked the baffling and it looks tight.  They removed the cylinder again and had 2 engine builders and the cylinder overhaul guy look at it and all said it looked fine with no issues.  And by the way it is a chrome cylinder not steel like I had thought.  They pressurized the intake and found no leaks.  Spark plugs all check fine.

The only thing different is that it is a chrome cylinder and not steel like the other 3.  I have 27 hours on the break in and the cylinder guy says the cylinder looks good.

So, they are at a loss as to what may be happening.  I consulted with JPI and they said to check the grounding which they did and check for shorts which they did.  If you do a full power run up on the ground the cylinder stays well below 400 degrees.  But on take off it hits 470 when about 800-1000 feet in the air and stays above 400 throughout the flight.

We have run out of ideas.  So I am grasping at straws here because the shop at my airport that did this work have kind of given up.  They haven't a clue what to do next.  I thought maybe putting a steel cylinder back on to see if that corrects it.  Maybe there is something with the cylinder that just can't be seen.  But I am not sure what to do next.  

Please feel free to ask any questions needed.  I will answer them as best as I can.

Thanks.

 

[takair]

15 minutes ago, Greg Ellis said:

I would like to post an update on this issue and see if anyone has any input (please see original post for initial history).  So the #3 cylinder continues to show a very high temperature on the EDM 900.  It hits about 470 at about 1000 feet on take off.  It will cool off in cruise but stays above 400 degrees when all other 3 cylinders are in the mid 300's.  A lot has been done to trouble shoot this since I first posted about it but to no avail.  The probes were swapped, no change. A new probe was put in.  No change.  The wires were checked for shorts and grounding issues, none were found.  They took the #1 and the #3 probes and put them in boiling water and they registered the correct temp on the EDM 900.  They have checked the baffling and it looks tight.  They removed the cylinder again and had 2 engine builders and the cylinder overhaul guy look at it and all said it looked fine with no issues.  And by the way it is a chrome cylinder not steel like I had thought.  They pressurized the intake and found no leaks.  Spark plugs all check fine.

The only thing different is that it is a chrome cylinder and not steel like the other 3.  I have 27 hours on the break in and the cylinder guy says the cylinder looks good.

So, they are at a loss as to what may be happening.  I consulted with JPI and they said to check the grounding which they did and check for shorts which they did.  If you do a full power run up on the ground the cylinder stays well below 400 degrees.  But on take off it hits 470 when about 800-1000 feet in the air and stays above 400 throughout the flight.

We have run out of ideas.  So I am grasping at straws here because the shop at my airport that did this work have kind of given up.  They haven't a clue what to do next.  I thought maybe putting a steel cylinder back on to see if that corrects it.  Maybe there is something with the cylinder that just can't be seen.  But I am not sure what to do next.  

Please feel free to ask any questions needed.  I will answer them as best as I can.

Thanks.

 

What rings do you have?  Steel cylinders run chrome rings, but you don’t want those running in a chrome cylinder.  Also, did they confirm ring gaps?  Too tight and they will run hot and/or break.  Apologies if this was covered previously.