Hotter running engine

[Grant_Waite]

I have a 1977M20J with the IO360 A3B6D.Ever since I got my plane back from a 3 month annual, the temps on all my cylinders have gone up 20-30°. The 2 things the shop fucked with were claiming they cleaned the fuel injectors, no way they did. Just cleaned them last week and they were quite dirty but not clogged. They also cleaned, and regapped all 8 of my champion fine wire plugs. My plane use to run perfectly fine in the 360s on the hottest, which was usually #4. I did have a baffle that was cracked and replaced it with a brand new one from Airforms. It didn’t change anything either. I had the timing checked on the mag and it was a half degree advanced, so I had it set back to 25°. They did say the internal timing was about a half degree off. It is almost  time for me to send my mag out for the 500hr. I’m getting that nothing is wrong or different from my mechanics but something changed from annual that’s casing it to run at 390+ when it’s 40° or less out. If sending the mags out and replacing all my baffle seals, doesn’t fix it then idk what else to do. I bought 4 tempest massives to put in #3 and #4 to see if the champions plugs are trashed. Champion is definitely not a champion company… previous owner loved Champion hence the plugs. I can’t justify putting in fine wires if there not going to solve the issue so the massives will have to do for testing. The plane was missing pretty good today when I was taxing it was just after getting fuel so the engine was hot. It’s always kinda missed and stumbled since I’ve owner it but today it definitely seemed worse. Everything else runs like a top and starts just fine, but it does seem to have more vibrations to me in flight. 

[Fritz1]

As you said something has changed, the combo mag has its intricacies, you may want to find somebody that really understands this mag and have it overhauled

[EricJ]

Those are different engine setttings, so you might expect some differences.  20F isn't a lot.

If you want to check something else, make sure the baffles are still folding inward on the cowl.    If the cowl wasn't replaced properly and the baffles fell the wrong way it'll affect the flow.

[Grant_Waite]

1 hour ago, Fritz1 said:

As you said something has changed, the combo mag has its intricacies, you may want to find somebody that really understands this mag and have it overhauled

The mag was overhauled in 2019 so I don’t think it needs it but it does need the 500hr done. I’m sending to Aero Accessories in Van Nuys but I’ve yet to call since they’ve been closed for Christmas 

[Grant_Waite]

1 hour ago, EricJ said:

Those are different engine setttings, so you might expect some differences.  20F isn't a lot.

If you want to check something else, make sure the baffles are still folding inward on the cowl.    If the cowl wasn't replaced properly and the baffles fell the wrong way it'll affect the flow.

The baffles all lay flat except the 2 back ones in 2 spots. I’m going to have all the baffles replaced whenever I send the mag out this month or next month. The baffles around the chin are original and need replacing badly. The one baffle on the right is new since this picture was taken. 

[Bartman]

Replace those worn out baffle seals with the ones made by @Gee Bee Aeroproducts

[Fritz1]

Baffles should contact the cowl with a preload, don't count on ram pressure to close the gaps, check with cowl on, use light and borescope to find gaps

[GeeBee]

He was cooler before and got hot after they worked on the engine. I don't think baffles wore significantly in the shop. Unless they used a "flower pot" to time the engine there is nothing to say the engine is actually set at 25 BTDC. Get your mag and timing squared away first.

[Grant_Waite]

2 hours ago, GeeBee said:

He was cooler before and got hot after they worked on the engine. I don't think baffles wore significantly in the shop. Unless they used a "flower pot" to time the engine there is nothing to say the engine is actually set at 25 BTDC. Get your mag and timing squared away first.

I watch my mechanics time it after the idiots at annual said they checked it. They used an electronic timer and found it was a half degree advanced. The only things I haven’t changed are spark plugs so I’m hoping maybe it could be that. All the baffles will get replaced when the mag gets sent off. 

[EricJ]

4 hours ago, GeeBee said:

He was cooler before and got hot after they worked on the engine. I don't think baffles wore significantly in the shop. Unless they used a "flower pot" to time the engine there is nothing to say the engine is actually set at 25 BTDC. Get your mag and timing squared away first.

A trick I learned somewhere, maybe in A&P school or here or somewhere else, is to sight a laser down the seam of the case halves toward the timing mark on the flywheel.   On many GA aircraft engines there's a boss or some other feature to easily assure that the laser is aligned with the case seam, and then point it at the timing mark on the flywheel.   Every time I've done both this and the coffee can method, it's both easier to do and easier to see small deviations from the timing mark using the laser.

[Grant_Waite]

1 hour ago, EricJ said:

A trick I learned somewhere, maybe in A&P school or here or somewhere else, is to sight a laser down the seam of the case halves toward the timing mark on the flywheel.   On many GA aircraft engines there's a boss or some other feature to easily assure that the laser is aligned with the case seam, and then point it at the timing mark on the flywheel.   Every time I've done both this and the coffee can method, it's both easier to do and easier to see small deviations from the timing mark using the laser.

My mechanics used a wrench to line up the marks to the case halves which not sure how accurate that was or wasn’t. The one who will remove the mag is a different mechanic that worked on the plane for the previous owner

[Gee Bee Aeroproducts]

16 hours ago, Grant_Waite said:

The baffles all lay flat except the 2 back ones in 2 spots. I’m going to have all the baffles replaced whenever I send the mag out this month or next month. The baffles around the chin are original and need replacing badly. The one baffle on the right is new since this picture was taken. 

Material thickness of seal not more than 3/32. .093

pretty lazy not to change the lower cowl

old baffle material makes for cracked baffles , ducts are home made , non finished ends .

Typical hack work I see from non professional mechanics.

[Grant_Waite]

12 minutes ago, Gee Bee Aeroproducts said:

Material thickness of seal not more than 3/32. .093

pretty lazy not to change the lower cowl

old baffle material makes for cracked baffles , ducts are home made , non finished ends .

Typical hack work I see from non professional mechanics.

Yeah, you’re telling me. It could definitely use all new scat tubing from you. Didn’t realize all the stuff you made for aircraft. Lots and lots of hacksmith stuff going on in the engine 

[Paul Thomas]

12 minutes ago, Gee Bee Aeroproducts said:

Material thickness of seal not more than 3/32. .093

pretty lazy not to change the lower cowl

old baffle material makes for cracked baffles , ducts are home made , non finished ends .

Typical hack work I see from non professional mechanics.

What is the optimal thickness? I would assume that too thick and it won't conform as well.

[GeeBee]

17 hours ago, Grant_Waite said:

I watch my mechanics time it after the idiots at annual said they checked it. They used an electronic timer and found it was a half degree advanced. The only things I haven’t changed are spark plugs so I’m hoping maybe it could be that. All the baffles will get replaced when the mag gets sent off. 

The buzz box is no guarantee. Every time I see a timing problem it is because people decided to use some new fangled tool. I've even seen guys screw up Time-Rite units. Put the shaft on TDC, hang a flower pot on the prop, go to 25BTDC. Done. 

Nice thing about the flower pot. It uses an un-relenting source. Gravity.

[Fritz1]

think the problem with the combo mag is the internal timing is set by two set of contacts and the external timing can only be set by rotating the single housing, so the contacts must be set exactly with the same correct gap for both mags to fire at the same time which is apparently difficult, but that is hearsay, I have never timed a combo mag myself, timing two mags with two housings is much easier, not so sensitive, you can rotate each housing individually to get the mags fire at exactly the same angle BTC, I use a metal pointer clamped to the one housing half in the separation plane so that it almost touches the flywheel, your can get the timing within less than .25 degrees with a good old buzzer, I put marks on painters tape on the mags to remember which way to turn for more or less advance

[Joe Linnebur]

14 hours ago, Bartman said:

Replace those worn out baffle seals with the ones made by @Gee Bee Aeroproducts

I second this! 

[201Steve]

Just one thing to consider, since you have the exact same airplane as me, when I ordered the baffle kit and duct kit from Guy, none of it fit right. It was all supposed to be specific to a 1977 Mooney 201 but, it was not. 
 

it’s nice stuff, but it isn’t cut right or at least wasn’t  for all of my stuff. I ended up throwing away all the baffling material, and had to pay for the corrected length duct. Guy said there must be something custom about my airplane (there isn’t) because it worked for other 77 J models and he doesn’t make mistakes. Although nice, if it doesn’t fit…. I wouldn’t try it again. Your results may vary. 

[Grant_Waite]

I already got new seals from Airforms, since I had to buy a new baffle. My one on the left side had a nice crack in it so it wasn’t working too well. But that didn’t fix the temps either. I think it’s most likely a mag thing since they have just about 500 or a littler over. 

[PT20J]

Half a degree engine to mag timing shouldn’t have much effect on CHT. Internal mag timing (E-gap) primarily affects spark intensity.

Lycoming SI 1437 describes two methods for setting timing. Method one won’t work on a M20J because the spinner backplate obscures the timing marks. Method two is what I use. The Lycoming tool is ungodly expensive, but many people just use a straight edge on the crankcase parting line. I use this tool which makes it easier and is reasonably priced.

https://www.aircraftspruce.com/catalog/topages/pointers.php?clickkey=1596921

[Bolter]

On 1/5/2025 at 6:57 PM, Grant_Waite said:

 They also cleaned, and regapped all 8 of my champion fine wire plugs. 

I thought we were not supposed to clean and re-gap fine wire plugs.  The wire is fragile and prone to breakage, plus they tend not to wear within their lifetime.  Not sure how well they handle traditional blasting like the massives do.  The shop may have messed up your plugs.  You did not mention removing and inspecting them.  Mag checks at runup may not detect all possible plug issues.  -dan

[jetdriven]

Ive never been able to use the gunsight down the spine to the flywheel marks worth a hoot.  Often, the marks on the flywheel and starter are visible. Those are great. In Grant's case, its using the metal threaded piston stop that indexes a rite-system digital angle gauge.  You can get repeatable results to about .1 or .2 degrees from different mechanics. We've had the first guy write it down, then zero the gauge and have the next guy do it. He gets the same number.  It goes out for annual. It flies 50hrs.  It comes back, we measure it again.  Then look at last years sheet, its the same too.

[Grant_Waite]

26 minutes ago, Bolter said:

I thought we were not supposed to clean and re-gap fine wire plugs.  The wire is fragile and prone to breakage, plus they tend not to wear within their lifetime.  Not sure how well they handle traditional blasting like the massives do.  The shop may have messed up your plugs.  You did not mention removing and inspecting them.  Mag checks at runup may not detect all possible plug issues.  -dan

That’s what I thought too, is that fine wires weren’t supposed to be gapped because you can mess them up. I have taken them out and they did make spark when we put them in the tester but I didn’t check to measure the gap. I read the log entry after this so I didn’t know they were taken and gapped at annual 

[Grant_Waite]

1 hour ago, jetdriven said:

Ive never been able to use the gunsight down the spine to the flywheel marks worth a hoot.  Often, the marks on the flywheel and starter are visible. Those are great. In Grant's case, its using the metal threaded piston stop that indexes a rite-system digital angle gauge.  You can get repeatable results to about .1 or .2 degrees from different mechanics. We've had the first guy write it down, then zero the gauge and have the next guy do it. He gets the same number.  It goes out for annual. It flies 50hrs.  It comes back, we measure it again.  Then look at last years sheet, its the same too.

I bought a Klein Inclinometer thinking I’d need it, but the guys that timed it said that’s only for Continentals. So that 50 dollar inclinometer wasn’t a waste then. Might have it rechecked before I send the mags off using the inclinometer.  This is the one I got. It comes with a nice base that’s magnetic and straps to hold it to the prop. 
https://www.amazon.com/Klein-Tools-935DAA-Digital-Electronic/dp/B0CSH23J3V/ref=mp_s_a_1_8_sspa?crid=15KLWBKS07ORW&dib=eyJ2IjoiMSJ9.i6aACVH5TXpMP850RfAtruoHeT4cfxmVur7Ap2EZVf6XmyXdgyydoAQWAonkmb9bRJVFHKQl3hLUAaq9_Nw6CEE-c275Ye13Aw5ItzaExhCFo38_qfKAkcNBdP5dp4VWJCW_euDpOlNjAy4BzxX3BXiWATiDbO8WtDCiBakcolxHYypJMb1yo8mBqZn0MpfKCYEydrD-3DoMGjrZ26sxxg.CCh1BqlcrVWcT9IWs201iJCMoKcOR8eTf0BlkGaB12g&dib_tag=se&keywords=klein%2Binclinometer&qid=1736225837&sprefix=klein%2Binc%2Caps%2C118&sr=8-8-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9zZWFyY2hfbXRm&psc=1&th=1

[Gee Bee Aeroproducts]

Ref sceet ducts finished 2” ends

1977

1978 to mse year

201 mse

There three versions of duct sizing

231

252

We add a extra inch or two for bettering routing and or bend .

With finished you can trim to your length.

Place the lined clamp around the amount of material you want to shorten and trim.

Breezeaerospacee 94 series clamp lined will not cut into the silicone cuff.

non finished ends will collapse and fail or bend in the end portion.

i also stock the two defrost ducts and we have made the overhead ducts per customer request.