Looking at a M20K 231

[Mike A]

25 minutes ago, jrwilson said:

This is frustrating.  You're not an expert, but you make a blanket statement about "The 231 has a problem engine as far as I'm concerned."  Do you mean early 231s with the -GB engine?  If so, yes, there were early problems, which have been largely rectified with the -LB engines.  Add an intercooler and Merlyn and it's a fantastic plane.  A low time pilot can't be trained to safely operate one?  Jeez, tell that to the military, which routinely teaches low time pilots to fly jets.  

Sure, it only has 10 more horsepower than the J, and it isn't "...all that much faster."  But by that logic, your Ovation 3 has 100 more horsepower, and isn't that much faster than my 231...in fact, maybe a bit slower.  

Throughout the history of the 231, it has been discussed by armchair critics who've never actually flown them and just repeat what they've heard from early reviews of early model 231's.  Maybe get some updated information on the 231 before making broad statements.  Sorry for the rant...

Let’s not forget that 10 horsepower gap rapidly grows as you climb.  I can get above 10,000’ in less than 15 minutes and leave a NA 201 in my wake with more than likely a smoother and cooler ride. 
 

Treat the TSIO-360 right and she will return the favor. 

[carusoam]

MS rule number one...

Try not frustrate the other MSers in front of the new guy searching for his first Mooney... 

There aren’t any bad Mooneys...

TC’d Mooneys have a clear altitude advantage over the non TC’d versions...

If you want that advantage, go TC!

If you write something in jest...  don’t be afraid to toss one of these in...   not everyone is going to understand the humor at all times....

PP thoughts only, not a website peace keeper...

Best regards,

-a-

 

Edited January 20, 2021 by carusoam

[RJBrown]

On 1/17/2021 at 6:48 PM, Mooney217RN said:

ElCid-

I am not an expert, but have been flying Mooney aircraft for 20+ years.  First aircraft, I'd steer clear of the 231.  Get a 201, an E or F model, all depending on your budget.  I think the 201's are overpriced in general, but a low time pilot can be trained to safely operate an E, F or J Model.  the 231 has a problem engine as far as I am concerned.  It's a whopping 10HP more than an E, F or J, so it's not all that much faster.  yes, it's a turbo - are you planning on regularly flying up above 12,000' MSL?  If so, could be a good plane for you.  Personally, if you're going the route of a 231, step up to a 252.

People like this one do a real service to buyers of 231s. Their uninformed posturing scares people off and pushes down prices.

A J may be the best N/A airplane ever built but it is a downright dog compared to a 231.

I’ve owned both. Before I bought a 231 I flew N9136N a near new 1992 MSE. First flew her in July of 1993 I loved flying that plane. I rented it about 20 times over the next year.

After flying high time Cessnas to learn how to fly that 18 month old MSE was the greatest airplane I’d ever flown. Until I flew a 231. I lived in Denver with MEAs of 16600’ just 15 miles to my west. The difference in safety and dispatch reliability is night and day.

by the way that 231 in Dothan is the most expensive 231 I’ve ever seen. Engine beyond TBO, original panel with a bad KNS80, paint and interior. No wastegate or intercooler. If money is no object and you want a blank canvas you could dump another hundred grand into it tomorrow.

[CharlesHuddleston]

So I will add in my own personal experience here. I bought N1157L from the US Marshal's Service, without logbooks, roughly 2.5 yrs ago. It had sat for a little over a year in the government's possession. Having said that, the prior owner had installed almost every option available to the airframe for an '82 K model. It had the LB engine, intercooler, Merlyn waste-gate, electric speed brakes, long range tanks, gap seals, one piece belly, etc... I had just over 100hrs and only had my PPL. After spending around 10k to get it in the air and flight-worthy, I have since dropped a LOT of money into it to 1. overhaul the engine to 0-time (including the turbo, mags, etc). 2. Replace all the donuts 3. Upgrade the avionics to an Aspen MAX system, and have replaced the interior on my own. It is a joy to fly, and the only thing left for me to replace is the factory oxygen tank and re-paint. Having said that, I usually fly 10-13,000 feet, have traveled all over the southeastern US, and to the Bahamas twice. 

I would agree whole-heartedly with Carusoam's above statement that there are no bad Mooneys. Only newer, older, prettier, uglier, airworthy, and non-airworthy variants. 

For me, having a great instructor (who also happened to be one of my best friends growing up) has been a huge plus. Getting experience in the seat of a complex, high-performance plane is a must. Learning how to adjust your RPM, MP, and fuel flow for different settings at different altitudes is something that comes with time in the seat. The engine monitor is a MUST in order to treat the engine correctly and to get it to TBO (or beyond). Having said all this, we all know people with more time or experience, that we would NEVER let fly our planes. On the other hand, you can usually tell very quickly if someone is up to the task and has the experience/knowledge base to make it work. 

Read and re-read all the different topics here an on other web-sites, and try to learn from other's mistakes. Let their costs save you time and money. And in the end, you will find the right bird to fit your mission and flying style! It truly is a magic carpet! Good luck!!!

[gsxrpilot]

Another Mooney owner here who's never owned a 231. When I was shopping for a turbo Mooney, I talked with and flew with more than a dozen 231 owners. There were two common themes.

1. Every single 231 owner I talked with, said to steer clear of the GB engine and make sure I found one with an LB engine.
2. And every 231 owner also said that if they could have found one, or could afford one, or would have know up front, they would have bought a 252.

I've been very happy with my 252 for the last 5 years.

[Tom 4536]

Wow! We are all very passionate about the planes we own and don't own. It seems I made a bad decision to buy my 231 and should probably sell it. Maybe I should wait until my GB engine starts having all the problems posted here. So far no engine problems in the 5 years I have owned the plane. I wish the rest of the equipment on the plane was as dependable as my GB engine has been.

[DonMuncy]

3 hours ago, gsxrpilot said:

Another Mooney owner here who's never owned a 231. When I was shopping for a turbo Mooney, I talked with and flew with more than a dozen 231 owners. There were two common themes.

1. Every single 231 owner I talked with, said to steer clear of the GB engine and make sure I found one with an LB engine.
2. And every 231 owner also said that if they could have found one, or could afford one, or would have know up front, they would have bought a 252.

I've been very happy with my 252 for the last 5 years.

You probably also should add a #3. We are happy with our 231s; just not quite as happy as we could have been.

[jlunseth]

Yeah, the 231 is a really good airplane. Probably that and the older J’s are the most underpriced aircraft in Mooney fleet. There is nothing wrong with the GB as long as you know its limits. If you want a mid-teen turbo and don’t try to push it higher in warm temps you can do fine with it. As far as I am concerned, the problem with the GB or even the LB is expectation versus reality. The marketing power settings in the POH just are not reality. The GB may have a 24k ceiling but good luck ever getting up there unless (1) it is really cold out and (2) you have a lot of time. The certification pilots must have been very patient. But the throttle “issue” is a nothing, I didn’t have a problem with it from my first time in the aircraft. The engine management is a little more complex, but not a problem with a good engine monitor, which can be said of every Mooney version. And man! can that thing do lean of peak! The untuned intake manifold is a little bit of an issue, If I had a wish to spend a few more hundred thou I would get an Acclaim with the better manifold, but the trade off would be more speed, less payload, in some so much less that a single pilot needs to go on a serious diet.

[Schllc]

11 hours ago, RJBrown said:

People like this one do a real service to buyers of 231s. Their uninformed posturing scares people off and pushes down prices.

A J may be the best N/A airplane ever built but it is a downright dog compared to a 231.

I’ve owned both. Before I bought a 231 I flew N9136N a near new 1992 MSE. First flew her in July of 1993 I loved flying that plane. I rented it about 20 times over the next year.

After flying high time Cessnas to learn how to fly that 18 month old MSE was the greatest airplane I’d ever flown. Until I flew a 231. I lived in Denver with MEAs of 16600’ just 15 miles to my west. The difference in safety and dispatch reliability is night and day.

by the way that 231 in Dothan is the most expensive 231 I’ve ever seen. Engine beyond TBO, original panel with a bad KNS80, paint and interior. No wastegate or intercooler. If money is no object and you want a blank canvas you could dump another hundred grand into it tomorrow.

It’s an LB engine and it has an intercooler, I reviewed the logs and it’s interesting, given the turn this thread had taken, that it made it this far on the original engine and cylinders.
The paint isn’t as bad as the pics, the interior is tired but serviceable, but the avionics are antiquated. 
I agree it’s overpriced, but the owner understands he is going to have to adjust. 
I wouldn’t pay more than $35k

[RJBrown]

The problem I alluded to in my first post was “following the factory POH” the pilot operating instructions were written by the sales department.

All they cared about was getting 200 knots/231 miles an hour. Operated by the book most engines burned out by 1200 hours. What we, as a community of 231 drivers, have learned about operating the GB/LB engines could have saved Mooney from the black eye they got. Operated conservatively they can be made to last. A waste gate, an intercooler and an engine monitor make up for 80% + of the improvements the 252 got. Only shortcoming is the unequal intake runners. Any engine sent back to Continental comes back as a LB. 

‘but,

the 252 is everything the K should have been. It is the Best, most efficient, airplane Mooney ever built.

but, just like politics, POWER CORRUPTS, I Loved my Rocket. It truly corrupted me for anything less.

[kortopates]

8 minutes ago, RJBrown said:

The problem I alluded to in my first post was “following the factory POH” the pilot operating instructions were written by the sales department.

All they cared about was getting 200 knots/231 miles an hour. Operated by the book most engines burned out by 1200 hours. What we, as a community of 231 drivers, have learned about operating the GB/LB engines could have saved Mooney from the black eye they got. Operated conservatively they can be made to last. A waste gate, an intercooler and an engine monitor make up for 80% + of the improvements the 252 got. Only shortcoming is the unequal intake runners. Any engine sent back to Continental comes back as a LB. 

‘but,

the 252 is everything the K should have been. It is the Best, most efficient, airplane Mooney ever built.

but, just like politics, POWER CORRUPTS, I Loved my Rocket. It truly corrupted me for anything less.

Overall good comparison, But as you know from your Rocket, 80% of a 252 is stretch because the Merlyn isn't an automatic wastegate. It merely changes the fixed wastegate into a manual variable wastegate which drastically improves the critical altitude and thus high altitude performance.

But also the GB didn't even have Pressurized magnetos, nit till the LB,  and surprisingly the Rocket didn't get them either, but at least RAM has an STC to add pressurized Mags to the Rocket TSIO-520. But there is just no comparison between an automatic hydraulic controller and wastegate compared to a manual Rayjay system. The 252 and Rocket are almost as easy to manage power as a J or R engine, but just need more respect towards temperatures.

[carusoam]

The cool thing about an M20K... it is more Mooney than an M20J... 

Unless you are really into efficiency...

Holy cow, the J still wins the efficiency war...

Each step up is more desirable, greater appreciated... and harder or challenging to add on later...

Looks like adding an intercooler would be the easy part...

The IC is available and has great reviews around here as well....

Best regards,

-a-

[Scott H Poms]

One adavantage of most 231's over the 252 is payload, the 231 has a bigger payload since it is lighter ( except for the Encore ) and I flew mine for years in the teens without an intercooler or a merlyn no problems flew fine and never ran out of throttle.  You just need to baby it a bit, engine monitor required!  I don't think many GB powerplants left out there and yes they only return an LB at rebuild.  I think the new Continental LB engines have a 2000 hour TBO from the factory now as well.  252 yes easier to manage  engine, bit quieter, better interior and more. 

Good article here on 252 vs 231

https://www.avweb.com/features/mooney-m20k-231-252/

 

 

[Ron McBride]

Can an MB engine be installed in a 231?

 

[kortopates]

2 minutes ago, Ron McBride said:

Can an MB engine be installed in a 231?

 

Years ago there was a 262 STC to do that by Modworks. That really was the best 231 option out there, still quite a few out there.

[carusoam]

Freeing up the mod works STCs...   will probably require an aviation attorney with a deep love of Mooneys...

The STC author has passed...

What could possibly stand in the way...  

Best regards,

-a-

[jlunseth]

On 1/17/2021 at 9:59 PM, whiskytango said:

My first 231 had a GB engine with no UDC or Intercooler.  I don't recommend it.  It was a struggle on hot days to maintain even a moderate climb rate without significantly exceeding 400 F CHT.  As much as I tried to keep CHTs below 400 F, during the 3 years that I owned it I ended up having 3 cylinders develop cracks and 1 complete cylinder barrel separation, resulting in an off-airport landing.  The previous owner had the alarm value on the JPI set for 460 F, so who knows what CHT he was operating at.  

The 231 I am flying now has an LB engine with a Merlyn UDC, intercooler and GAMIs.  It is like flying a different airplane, and I can recommend it.  I too would prefer to have a 252 with the MB engine, but none were available when I was buying.

That 460 setting would be the redline out of the POH. When JPI set up my 930 they also probably put 460 in as the redline limit, but I never get close to that. On hot days, out west and in the climb, it can be pretty hard to keep the temp under 400 on one or two cylinders. A significant issue there is that no matter how hard I try, I cannot get A&Ps to set the max full power fuel flow up to the 24 GPH that is in the POH, it is always down around 21-22. I think I understand the reasons for that, but full rich fuel flow is what keeps temps down in the climb, that and not trying to climb at max climb rate. I keep the climb rate at a steady 500 fpm.

[Jack Burson]

I have owned two 231s - one with the GB engine no merlin or intercooler and one with the LB plus merlin & intercooler.  

The one with GB engine was picked up at the factory new - had it for 8 years.  Never had an issue with the engine - never got it above 22K though...

The one with LB engine I had for 14 years never had an issue with the engine.  IMHO - depends more on how you manage the engine.  If you are careful with throttle (slow & steady movements), pay attention to temps and avoid shock cooling it works fine.

Side note:  the one I bought new in 1981 (still with GB) came on the market about 2 years ago & I bought it again & am loving it.  I currently have 1200+ hours on the engine - no problems so far.

Update:  I'm in the process of adding the Merlyn wastegate controller...

Edited February 11, 2021 by Jack Burson

[jlunseth]

2 minutes ago, Jack Burson said:

I have owned two 231s - one with the GB engine no merlin or intercooler and one with the LB plus merlin & intercooler.  

The one with GB engine was picked up at the factory new - had it for 8 years.  Never had an issue with the engine - never got it above 22K though...

The one with LB engine I had for 14 years never had an issue with the engine.  IMHO - depends more on how you manage the engine.  If you are careful with throttle (slow & steady movements), pay attention to temps and avoid shock cooling it works fine.

Side note:  the one I bought new in 1981 (still with GB) came on the market about 2 years ago & I bought it again & am loving it.  I currently have 1200+ hours on the engine - no problems so far.

The "slow and steady" is more an issue for the non-Merlyn engine. The Merlyn puts a stop to bootstrapping. You can shove the throttle in fairly fast. What might cause an issue is that the prop governor might not catch up right away, so you could see a small amount of overspin with a sensitive modern engine monitor (i.e 2740). That said, the pilot can overboost the engine by firewalling the throttle on takeoff, you don't want to do that. And if you are trying to fine tune MP to, say, 34" instead of 34.3 inches, it takes very small throttle movements and probably a few tries to get it exact. Have often thought a vernier throttle would be good.

[carusoam]

+1 vernier throttle control...

It does everything the ordinary throttle control can do... and...

Dial in every 0.1gph that you want...

If you dial in 0.1gph too many... you can easily dial it right back out... with precision...

Probably really helpful for maintaining TIT...

PP thoughts only, not a CFI...

Best regards,

-a-

 

Hey Jack!  Long time, no see... averaging near two posts per year...   

[whiskytango]

On 1/27/2021 at 10:45 AM, jlunseth said:

That 460 setting would be the redline out of the POH. When JPI set up my 930 they also probably put 460 in as the redline limit, but I never get close to that. On hot days, out west and in the climb, it can be pretty hard to keep the temp under 400 on one or two cylinders. A significant issue there is that no matter how hard I try, I cannot get A&Ps to set the max full power fuel flow up to the 24 GPH that is in the POH, it is always down around 21-22. I think I understand the reasons for that, but full rich fuel flow is what keeps temps down in the climb, that and not trying to climb at max climb rate. I keep the climb rate at a steady 500 fpm.

I too have not been able to get my A&P to adjust max fuel flow for 24 GPH.  The most I ever see is 22 GPH at 36 inches MAP.  The A&P who installed my overhauled LB engine in 2019 set it up for 18 GPH maximum, which was way too low to prevent engine overheating in the climb.  After the first flight I requested my A&P to adjust FF up to 24 GPH, but it only does 22 GPH, and my No. 5 cylinder CHT limits climb to 700 FPM in anything but winter weather.  I reminded the A&P that this intercooled engine cannot be operated over 36 inches MAP, and to set up fuel flow based on that limitation.  I wonder if he saw the 40 inch MAP redline on the MAP gage (which applied to the engine before the Merlin UDC and intercooler were added) and set max FF for that MAP.

[Mike A]

6 hours ago, whiskytango said:

I too have not been able to get my A&P to adjust max fuel flow for 24 GPH.  The most I ever see is 22 GPH at 36 inches MAP.  The A&P who installed my overhauled LB engine in 2019 set it up for 18 GPH maximum, which was way too low to prevent engine overheating in the climb.  After the first flight I requested my A&P to adjust FF up to 24 GPH, but it only does 22 GPH, and my No. 5 cylinder CHT limits climb to 700 FPM in anything but winter weather.  I reminded the A&P that this intercooled engine cannot be operated over 36 inches MAP, and to set up fuel flow based on that limitation.  I wonder if he saw the 40 inch MAP redline on the MAP gage (which applied to the engine before the Merlin UDC and intercooler were added) and set max FF for that MAP.

Take an hour flight and go visit Joey Cole. He will set it up right. I see 25+ gph on the takeoff roll after he corrected another A&P’s disaster setup on my engine. 

[LANCECASPER]

On 1/20/2021 at 9:48 PM, RJBrown said:

the 252 is everything the K should have been. It is the Best, most efficient, airplane Mooney ever built.

The Encore was everything that the 252 should have been.

[jlunseth]

On 1/28/2021 at 11:46 PM, whiskytango said:

I too have not been able to get my A&P to adjust max fuel flow for 24 GPH.  The most I ever see is 22 GPH at 36 inches MAP.  The A&P who installed my overhauled LB engine in 2019 set it up for 18 GPH maximum, which was way too low to prevent engine overheating in the climb.  After the first flight I requested my A&P to adjust FF up to 24 GPH, but it only does 22 GPH, and my No. 5 cylinder CHT limits climb to 700 FPM in anything but winter weather.  I reminded the A&P that this intercooled engine cannot be operated over 36 inches MAP, and to set up fuel flow based on that limitation.  I wonder if he saw the 40 inch MAP redline on the MAP gage (which applied to the engine before the Merlin UDC and intercooler were added) and set max FF for that MAP.

You should get a copy of the Turboplus STC and give that to him. It has specific instructions for modifying the - SID 97-3 (something). The "something" part is that they continually update the SID, so there is a letter at the end and the last time I looked I think it was G. Here is what you will find. The STC requires making adjustments to the manifold pressure at which fuel flow is set depending on ambient pressure and temp. Generally, the fuel setting is made at a number somewhere around 37", rather than the 40" in the POH or the 36" we have all been told. It has always seemed to me that there is an abrupt rise in the fuel flow when the engine is at full power, meaning that every inch or even decimal place will marketly affect the flow. As you probably know, it is not easy to set the TSIO360LB to the tenth of an inch. The fuel flow settings in the SID are made from that base.

I have come to the conclusion that it is wrong to think the engine should not be operated at more than 36", depending on flight regime. Here's why. On the ground, while a maintenance run up is being conducted, the aircraft is not moving and therefore the cooling airflow over the intercooler is not what it would be in flight. Nearly the same thing happens on takeoff, until the aircraft picks up some speed. Moreover, the Turboplus STC uses a higher number, as I said, around 37 or even higher, for the max fuel flow setting. That said, I still don't like operating the engine for a prolonged period, such as in a climb to the flight levels, at a number over 36", but bear in mind that if you do as I do, you are likely not operating at full power. Certainly you are not operating the engine where the STC says you should be for full fuel flow, so you are going to get something in the 22 range from my experience, not 24 gph. That is if the mechanic set the fuel up exactly according to the STC. "Do not operate over 36" " is something we have all read somewhere, but it is not in the POH

I have on occasion gotten my mechanic to set the fuel a little higher, 25GPH. I then need to manage the throttle a little more to keep the fuel flow at 24" which is the POH max. As you know, the throttle and fuel flow are interlinked, so if you firewall the fuel flow and then put in 36" MP, the fuel flow automatically rises. If you put in 37" it rises higher still.

The other issue is the low idle setting. I think the mechanics set the max fuel first, and then they screw the idle adjustment down to where they want it. But the two seem to be interconnected, so that lowers the max fuel even if they set it right to begin with. They need to do it the other way around, set the low fuel first and then tweak the max flow to whatever setting is desired. That results in a slightly higher fuel flow at idle, but it is not idle fuel flow that we worry about in the 231, it is the full power climb to altitude.

I wish I knew the magic bullet to get it set correctly every time.

[Goldonomic]

On 1/19/2021 at 1:05 PM, Mike A said:

Let’s not forget that 10 horsepower gap rapidly grows as you climb.  I can get above 10,000’ in less than 15 minutes and leave a NA 201 in my wake with more than likely a smoother and cooler ride. 
 

Treat the TSIO-360 right and she will return the favor. 

I owned a M231 for years and I must admit that it was a wonderful airplane..even with the GB3 engine which never gave up. I flew it 5 times across the Atlantic. I flew it all the way over Africa...to Cape Town. I flew it at FL300 (and it was still climbing). I used to fly a direct Goose Bay to Reykjavik, Iceland....over all the years, I did have some minor incidents. I remember the  broken turbo clamp somewhere between Goose Bay and Keflavik. Once I had a broken vacuum pump (at night when making an approach to Cape Town), ...It is a wonderful airplane and cheap to maintain.