TIO 540 AF1B cylinder replacement

[estroodle]

We are looking to replace a cylinder for a Lycoming TIO 540 AF1B engine on a M20M.  New or used and serviceable cylinder.  Any suggestions for shops or dealers that can help?  Our current vendor estimates a January delivery date but we would really love sooner.  Thanks in advance!

[LANCECASPER]

2 hours ago, estroodle said:

We are looking to replace a cylinder for a Lycoming TIO 540 AF1B engine on a M20M.  New or used and serviceable cylinder.  Any suggestions for shops or dealers that can help?  Our current vendor estimates a January delivery date but we would really love sooner.  Thanks in advance!

If Air Power can get you a new cylinder in three months you should be thrilled. No one else is going to get you a cylinder any sooner. About three years ago there was an 18 month wait on TIO-540-AF1B cylinders. I wouldn't waste the labor cost on a used cylinder, especially on this engine since people run them too hot. Even having a cylinder rebuilt will take you longer than January since the parts that are always backordered on these cylinders are the exhaust valves and guides.

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This is way more info that you asked for . . . . You may have owned your Bravo for years, but since you're new on Mooneyspace I'm going to share some information on what temperatures work for this engine. If you run it by the POH you will burn up cylinders, turbos, exhaust systems and maybe occupants.

Normally we all think of the POH as the final authority but if you take into account all of the experience that Bravo owners on this forum have, in 36 years now since the M20M was introduced, the recommended setting for longevity on this engine is a max combined number of 53 (MP + RPM; Example 29MP + 2400RPM). The people that run 34/2400 will be buying cylinders often. Even 32/2400 will never make TBO.

Also keeping the TIT below 1600 will prolong the cylinders (especially the exhaust valves), exhaust system, turbos and TIT probes. The POH was never revised from the original and it says 1750 max, but that's when in the early life of the M20M people were going through a set of cylinders every 200-300 hours. The early M20M owners fought the battle and eventually Lycoming developed the wet-head (Bravo) engine, which helped. However still even with the Bravo (wet-head) engine you'll still never hit TBO if you run POH numbers.

The other big thing with this engine is that the TIT probes really only last 200-300 hours - less if you run it hotter than 1600. When the probes fail the TIT reads low, compounding the problems. As an example someone runs it at 1650 indicated when in fact the TIT is really 1750 since the probe is bad. This will mean turbo overhaul, exhaust overhaul and cylinder replacements. Looking over the logs and seeing when the probe was last replaced is very important.

Every time you have the engine cowl off carefully inspect your exhaust system as if your life depended on it, since it does. A few Bravo accidents occurred when the exhaust system burned through (especially the "Y" in the tailpipe) or the early spot-welded Turbo V-Clamp gave way and 1600-1700 exhaust gases burned through the firewall and it didn't end well for the pilot and passengers. Make sure that a soapy water pressure test is done on the exhaust at every annual and that it's visually inspected at every 25 hour oil change (Yes this is one of the few engines that Lycoming says it is mandatory that 25 hour oil changes must be done - Lycoming SB 480F).

I've had three M20Ms and there are a lot of other people on here with a lot of M20M time as well and that's what we have learned so far. 

 

[mike_elliott]

Solid ^^

[Fritz1]

I am ordering a cylinder today so I have it and never need it, 3 months is awesome!

[Fritz1]

If you are dropping the exhaust and it has more than 1000h and most of it was put on by a previous owner overhauling that exhaust might be an excellent idea for the reasons stated above. There is an SB installing an additional firewall baffle above the wastegate and behind the turbo transition Y, make sure that is installed

[hazek]

1 hour ago, Fritz1 said:

There is an SB installing an additional firewall baffle above the wastegate

Link to SB?

[estroodle]

I figured Air Power would be our best/only option. 

Thanks for the great advice!  The last time we replaced a cylinder we lucked into one of six on the planet that was immediately available.  We aren't as lucky this time around.  A benched spare would have been a great idea looking back as the prices won't ever come back down.  At that time we also did a complete exhaust overhaul so those bits were addressed.

As for the recommended settings for running the engine, I had never heard of the "53 rule".  What a concise way to describe optimal running conditions.   We service the engine "on condition" with analysis using the Savvy method.  Savvy recommended usage is in line with what you described above; keep TIT 1600 or less, run 75-80% HP during cruise which comes out to roughly 53-54 using the rule LANCECASPER describes.  Finally, monitoring TIT probe age is invaluable advice.  Ours had probably aged out prior to the last cylinder servicing and was subsequently replaced.  Looking back at the flights after replacement there was a notable increase in EGT/TIT temps that we summed up to be related to a properly working probe.  Who knows if we could have avoided some of the exhaust woes we went through had we replaced the probe sooner?   

[Fritz1]

will check on the firewall SB, replaced wastegate last year and SB is somewhere in the paperwork, as for overhaling that cylinder if you must, It cannot be bored since nitride hardened, can only be honed, as stated before availability of exhaust valve and guide will determine timing, I have heard good things about Gann aviation and Gibson cylinders, when in doubt call Jimmy Garrison at GmaxAmerican, think he still has a personal Bravo and might know where a cylinder can be found, welcome aboard! 

[LANCECASPER]

7 hours ago, hazek said:

Link to SB?

Service Bulletins are easy to find. https://mooney.com/contact-2/

Scroll down and select your model and then you'll see all of the Service Bulletins for your airframe. You can find them as easily as anyone else can on here.

(The one that was referred to was SBM20-283A. This one also covers the riveted V-Clamp requirement.)

[estroodle]

Update:

We sourced a cylinder, Fritz1 to the rescue!  Gibson cylinders was able to provide a rebuilt cylinder.  Thanks all for your help/feedback.  I think going forward we may also bench a spare.  What a wonderful community, I appreciate the guidance!

[LANCECASPER]

On 10/8/2025 at 7:04 PM, estroodle said:

Update:

We sourced a cylinder, Fritz1 to the rescue!  Gibson cylinders was able to provide a rebuilt cylinder.  Thanks all for your help/feedback.  I think going forward we may also bench a spare.  What a wonderful community, I appreciate the guidance!

Each person gets to make this choice, but I personally wouldn't put a Gibson cylinder on an airplane I owned. They are the go-to for people doing "cheap" field overhauls. Sellers who are "fixing" an airplane right before they sell it use Gibson, and the cylinder will last for a few hundred hours. Paying all of the labor to remove the old cylinder and replace it with a Gibson is money you'll never get back. If you're set on going with a repaired cylinder I would just send the one you have to Gann or J & J Air Parts in Pleasanton TX. (https://www.jjairparts.com/)

 

Example: Gibson doesn't even realize that this cylinder is for an -AF1B engine. They have it listed for an -AFIB. That may give you an idea of their attention to detail.     https://www.gibsonaviationok.com/class-38-2

They also have a lot of "as needed" in the description of their work. Particularly on these cylinders the exhaust valve guide has to be replaced, not just "as needed" - they all need it.

 

[Fritz1]

Lance has a good point, my personal choice would have been Gann, comes down to the question are the exhaust valve and the guide available and what does the bore of the existing cylinder look like

[Fritz1]

called airpower since they were showing stock, ordered one and will put under X-mas tree