Mooney 231 PPI Items

[malyce7]

Greetings all!  I have owned a non-turbo Piper Arrow III for about 16 years now, and it's been a great plane for being single, then married, then married with 2 kids.  Easy to maintain, reasonably capable and comfy to fly in, even coast-to-coast a few times.  After many years I've decided to trade platforms and look for a 231.  I met one gent at CZL a few weeks ago that let me poke around his 231 a bit (I was flying the wife's C152), and it's comparable to the Arrow in terms of cabin space and whatnot. 

I've poked around the interwebs enough to learn some basics about the Mooney model I'm interested in, but was curious about some of the things to look for in a potential purchase- both what you might consider "mandatory" versus "Preferred."

My typical flying will be from TN to NY/NC/FL, with jaunts to ID/WA 2-4 times a year.  Will probably fly 55-65% power, but mainly interested in comfortable cruise in the 10-12k range, with hops up to 18-20k for the Rocky Mountains.  I've read up on the test pilot writeup that seems to be everywhere that Mooney discussions seem to be, and lurked these forums quite a bit for tidbits here and there.  

It seems the best things to look for are the LB engine, single-piece belly, intercooler, and Merlyn Wastegate.  Not all mandatory items, but good to have.

What sort of things would be a no-go for a M20K related to the airframe and engine?

 

Edited April 22, 2020 by malyce7

[Oldguy]

Welcome aboard, @malyce7! I will throw out some of the general things I see mentioned on here from the turbo guys and some of my own NA thoughts as well.

1. Corrosion in the frame is a killer so look for a SB208B inspection having been done in the recent past.
2. While not mandatory, a recording engine monitor will let you manage your engine better than just getting it "close enough". It may also show you how to previous owner ran it. 
3. The Continental IO-360s seem to need a top overhaul if not run appropriately about halfway to TBO, so a good PPI on a mid-time engine (900-1200 hrs) will serve you well.
4. Leaking tanks will cost ~$8,000 to get both stripped and sealed if leaking. They are not necessarily a no-go, but a significant cost consideration if leaking. If recently sealed by one of the better known places (Weep No More, Houston Tank Specialists, etc.) then the plane would typically come with a transferable warranty for several years and be considered something of value.
5. Being maintained by a Mooney Service Center (MSC) in the past is a plus, but have a different MSC do the PPI. And while it does not have to be a MSC in either of those situations, without Mooney expertise, it is a crap-shoot  to expect them to find Mooney-specific problems.

This is a start on some things which may be different from the NA Arrow you have been flying. There are a bunch of additional items relating to autopilots, glass screens, GPS, etc. but they usually come down to personal preference and what you are used to using.

Best of luck on your search, and keep us informed on how it progresses.

[gsxrpilot]

1 hour ago, malyce7 said:

What sort of things would be a no-go for a M20K related to the airframe and engine?

The first no-go M20K for me is the 231. Look for a 252. 

But on a more serious note... if a 231, look for one with the LB engine upgrade. I'd stay away from the GB engine. And a later model version, like 1986 or so, will have the removable back seats which are one of the nicest interior features in a Mooney, if you ask me.

[Guest]

There is a nice TKS equipped 252 owned by a Mooneyspace member for sale.  I’ve no stake in the plane, but could complete a PPI for you.

https://www.controller.com/listings/aircraft/for-sale/191592877/1986-mooney-m20k-252tse

Clarence

[MIm20c]

9 minutes ago, M20Doc said:

There is a nice TKS equipped 252 owned by a Mooneyspace member for sale.  I’ve no stake in the plane, but could complete a PPI for you.

https://www.controller.com/listings/aircraft/for-sale/191592877/1986-mooney-m20k-252tse

Clarence

Every time I see a plane listed north of the border I always ask myself...is it close enough for Clarence to pop the hood. 

[DonMuncy]

When I started shopping for a Mooney, I was not aware of the differences between the 231 and the 252. I am happy with my 231. It is a good plane, but one of my frequent laments is that I didn't get a 252. If you can stand the price differential and can find one, get a 252. If not a 231 is still a fine plane. Don't get one which has not been converted for GB to LB unless you factor in the cost to convert.

[carusoam]

231, 252, Rocket, 262...

LB, MB, TSIO360, TSIO520....

MP controller, intercooler, engine instrumentation...

 

Things to become familiar with while determining if a 231 is the right plane for you...

Any one will be better than the Brand P being set out to pasture...
 

The independent PPI by a Mooney specific mechanic... is the best protection for your wallet...

PP thoughts only, not a mechanic...

Best regards,

-a-

 

[ArtVandelay]

There is a nice TKS equipped 252 owned by a Mooneyspace member for sale.  I’ve no stake in the plane, but could complete a PPI for you.
https://www.controller.com/listings/aircraft/for-sale/191592877/1986-mooney-m20k-252tse
Clarence

If I read the W&B correctly, you can’t fly this plane solo with full fuel unless you weigh 100lbs.

[gsxrpilot]

28 minutes ago, ArtVandelay said:

If I read the W&B correctly, you can’t fly this plane solo with full fuel unless you weigh 100lbs.

This desperately needs a full panel makeover to reduce weight... and an Encore upgrade.  But it's a TKS 252 which is s great platform to start with.

[Niko182]

18 minutes ago, gsxrpilot said:

This desperately needs a full panel makeover to reduce weight... and an Encore upgrade.  But it's a TKS 252 which is s great platform to start with.

does it fall under the serial numbers to be able to be upgraded to an encore?

[gsxrpilot]

17 minutes ago, Niko182 said:

does it fall under the serial numbers to be able to be upgraded to an encore?

Good question. It's one of the earlier 252's.

[LANCECASPER]

6 hours ago, gsxrpilot said:

The first no-go M20K for me is the 231. Look for a 252. 

But on a more serious note... if a 231, look for one with the LB engine upgrade. I'd stay away from the GB engine. And a later model version, like 1986 or so, will have the removable back seats which are one of the nicest interior features in a Mooney, if you ask me.

All '86 and newer K models were 252s, so once again @gsxrpilot , subtly, wants you to get a 252. (The 231 ran through 1985)

If I remember right the 83's and on had removable back seats, but I'm pretty sure that 84's and newer had the one piece belly.

@malyce7  here's a pre-buy article from MAPA years ago. 

M20K PRE-BUY.pdf

[Brian E.]

2 hours ago, LANCECASPER said:

here's a pre-buy article from MAPA years ago.

Great article.  Not in the the market but I want one.

[squeaky.stow]

4 hours ago, gsxrpilot said:

This desperately needs a full panel makeover to reduce weight... and an Encore upgrade.  But it's a TKS 252 which is s great platform to start with.

The Encore upgrade is on my to-do list if it doesn’t sell. Frankly I am not expecting it to sell during the current health/market crisis, but I am not in a hurry. Anyone on Mooneyspace that can advise me on where to find a copy of the engineering drawings and any good sources for used landing gear doors and brake parts would be my new best friend. The additional 230 lbs of useful load would be nice.
Panel upgrade is further down the list. I do plan to do ADSB this year but the urgency is not the same here in Canada. I am waiting for a good deal. As much as I would love to replace everything else with new fancy glass, every time I do the math I come back to the fact that it will buy me absolutely no additional utility and everything I have is working just fine. I don’t like how cluttered my panel is,  but I do like redundancy when flying IFR. That I have in spades. 
 

[squeaky.stow]

5 hours ago, ArtVandelay said:

If I read the W&B correctly, you can’t fly this plane solo with full fuel unless you weigh 100lbs.

That’s just about right. I have never actually flown it with full tanks. One reason for that (other than being 65 lbs too heavy) is that I can’t imagine flying my Moony for 10 hours! 

My typical load is myself and my wife, a couple of bags, and 5 hours of fuel. If I do the Encore conversion I can fill the long range tanks to the brim and still bring the wife and her purse, but she will want to stop for a break after 3 hours.

[Hank]

9 minutes ago, squeaky.stow said:

The Encore upgrade is on my to-do list if it doesn’t sell. Frankly I am not expecting it to sell during the current health/market crisis, but I am not in a hurry. Anyone on Mooneyspace that can advise me on where to find a copy of the engineering drawings and any good sources for used landing gear doors and brake parts would be my new best friend. The additional 230 lbs of useful load would be nice.

@Parker_Woodruff, how much of this do you still have / remember?

[gsxrpilot]

1 hour ago, squeaky.stow said:

The Encore upgrade is on my to-do list if it doesn’t sell. Frankly I am not expecting it to sell during the current health/market crisis, but I am not in a hurry. Anyone on Mooneyspace that can advise me on where to find a copy of the engineering drawings and any good sources for used landing gear doors and brake parts would be my new best friend. The additional 230 lbs of useful load would be nice.
Panel upgrade is further down the list. I do plan to do ADSB this year but the urgency is not the same here in Canada. I am waiting for a good deal. As much as I would love to replace everything else with new fancy glass, every time I do the math I come back to the fact that it will buy me absolutely no additional utility and everything I have is working just fine. I don’t like how cluttered my panel is,  but I do like redundancy when flying IFR. That I have in spades. 
 

I only mentioned the panel from a useful load perspective. A modern, no vacuum panel, might net you 50 lbs. That standby vacuum pump in the tail is 25 lbs by its self.

[Parker_Woodruff]

1 hour ago, Hank said:

@Parker_Woodruff, how much of this do you still have / remember?

Don Maxwell could get it for him for sure.

[squeaky.stow]

The drawings or the parts?

[squeaky.stow]

24 minutes ago, gsxrpilot said:

A modern, no vacuum panel, might net you 50 lbs. That standby vacuum pump in the tail is 25 lbs by its self.

That low hanging fruit has been picked. All vacuum instruments and standby pump are removed. My backup AI is electric with an external backup battery. Getting rid of the steam gauges might net me another 15-20 lbs but it would cost me either an extra Aspen and the Max upgrade or something even more expensive from Garmin. 
All of this could be rationalized if it was my forever airplane. Less so if I plan to trade up.

[gsxrpilot]

6 minutes ago, squeaky.stow said:

The drawings or the parts?

Both

[gsxrpilot]

6 minutes ago, squeaky.stow said:

That low hanging fruit has been picked. All vacuum instruments and standby pump are removed. My backup AI is electric with an external backup battery. Getting rid of the steam gauges might net me another 15-20 lbs but it would cost me either an extra Aspen and the Max upgrade or something even more expensive from Garmin. 
All of this could be rationalized if it was my forever airplane. Less so if I plan to trade up.

As you're selling the plane, I wouldn't do anything to it. If I was a buyer, the only negative is the useful load and I see ways to mitigate that with an Encore upgrade. But I'd let the buyer do that. 

I was seriously considering a 231 until I learned that a 252 could get significantly better useful load because of the Encore conversion. To my mind, that's a huge benefit of a 252. 

Mooneys are always short on useful load. But the F, Eagle, and Encore, can all have over 1000 lbs of useful load. And 252's can be converted to Encores. 

[CharlesHuddleston]

7 hours ago, LANCECASPER said:

If I remember right the 83's and on had removable back seats, but I'm pretty sure that 84's and newer had the one piece belly.

My '82K has removable seats! But, it also has the one piece belly, which I know was added on...

[Mike A]

22 hours ago, malyce7 said:

I met one gent at CZL a few weeks ago that let me poke around his 231 a bit (I was flying the wife's C152), and it's comparable to the Arrow in terms of cabin space and whatnot. 

@malyce7  Hey there!  I was that gent!  Glad you are continuing your search. If you want to meander over to MQY sometime soon I’m happy to get you up for a flight. 

[Warren]

I made the decision to buy a 231 based on the price being lower than a 252.  Here are a few thoughts and some of the differences I think are most important.  Nothing about avionics listed as there are many other sources for this information.

1.       Intercooler and Merlyn Upper Deck Pressure controller.  With the upgrades to add an intercooler and an upper deck pressure controller you significantly close the gap to a 252.  Still have to manage boost pressure manually (becomes second nature after a few flights).  I know intercoolers are still available for about 10k, not sure about the Merlyn controllers if you buy one without these.  I believe both of these should be mandatory upgrades on a 231.

2.       Encore Upgrade.  The 231 doesn’t have the option to upgrade to the Encore.  Mine is partially upgraded to glass, has the backup vacuum removed, went to a MT prop (15lb lighter) and has a useful load of 920 lb.  Knowing the Encore is rated almost 200 lb heavier with the same wing and 10 additional hp gives me comfort loading up to max gross weight with no concerns.

3.       LB Engine.  As stated above…the GB engine is less ideal than the LB and requires more conservative operation.  There are also some 231’s that have been upgraded to the MB engine which effectively makes them a 252 with a 12V system.

4.       231’s are all 12V and 252’s are 24V – many, if not all of the 252’s, have backup alternators while the 231’s need an aftermarket add-on if you want this.  There is some safety redundancy here.

5.       The removable rear seats in the later 231’s (guessing approx. 1982 forward) is a huge convenience.  I can put two road bikes or two mountain bikes in my plane with the rear seats out.  It takes about 2 mins to remove the rear seats.

Good luck with your search.  If you can afford a 252 or Encore they offer more performance for more money.  You will have to determine what you can afford and the best “bang for the buck” tradeoff’s.