Upgrading a 252 to the Encore's engine

[Parker_Woodruff]

Does anyone have knowledge on what the requirements are to upgrade a 252 to the Encore's 220 hp engine?  Does it mean buying a brand-new engine, or has anyone been able to work out an overhaul/exchange swap with the factory?

It sure seems like a great deal to upgrade the fairly low useful load of a late 80's M20K by 230lbs.

Also, is a new prop required?

[Geoff]

Parker,

Talk to the guys at Lone Star Aero, I took this from their website...

M20K 252 Encore from MB to SB engine

Converts “MB” to “SB” by changing fuel pump, turbo charger controller and prop governor,

changes control surface, counter weights and remarked gauges, and installs dual piston brake

pads. Increases gross weight to 3,130 lbs, BHP changes to 220@2,600 RPM.

[Parker_Woodruff]

Quote: Geoff

Parker,

Talk to the guys at Lone Star Aero, I took this from their website...

M20K 252 Encore from MB to SB engine

Converts “MB” to “SB” by changing fuel pump, turbo charger controller and prop governor,

changes control surface, counter weights and remarked gauges, and installs dual piston brake

pads. Increases gross weight to 3,130 lbs, BHP changes to 220@2,600 RPM.

[KSMooniac]

Someone on one of the email lists did this a couple years ago, and it wasn't that extensive nor really expensive relative to the increased capability.  I don't remember the costs off the top of my head, but it seemed reasonable to me.  I think it makes more sense to do it at overhaul time to avoid paying double labor for R&R, but who knows...

[Parker_Woodruff]

Quote: KSMooniac

I think it makes more sense to do it at overhaul time to avoid paying double labor for R&R, but who knows...

[kortopates]

Although probably easiest to do the upgrade duirng an engine change, its also straightforward to reconfigure one current TSIO-360-MB to the SB. Its also possible to do it in two stages, which is what I am intending to eventually do. The main airframe change is to put on double puck brakes, which can be done as the first step. A Mooney Drawing provides the details and they have a kit for the brake parts. The double puck brakes will bring back the shorter stopping distances with the increased max gross weight.

Another Mooney drawing will provides the details of the engine changes which basically involves i) having the fuel pump and pop-off valve overhauled to be set up for the SB configuration with its greater max MP, ii) and adjusting the governor back down to 2600 RPM max and iii) with the engines changes come some additional airframe and instrumentation changes: the airspeed indicator, MP gauge and RPM gauge will have to be re-marked, Encore control balance weights must be installed to replace the 252 balance weights (aileron, elevator and lower rudder) and lastly update (mostly Section 5) of the POH with the Encore POH pertinent parts. In lieu of remarking the old MP and RPM instruments its probably a good time to upgrade to an approved digital unit(s). Alternately of course, one could use their MB core as a trade-in towards a TCM new or rebuilt SB engine or just have their MB field overhauled to the SB configuration.

One can get both the Engine and Brake upgrade drawings from the factory to get all the details of the upgrade process. A owner that's also an A&P like myself can pull this off pretty easily in stages. I was about to start when the factory was furloughing people and at that time they needed 6 weeks to put together the brake kit. I haven't inquired how long it would take since then and put the project on the back burner for awhile.

[Parker_Woodruff]

Good info, Paul.  Thanks!

[fantom]

Parker...you're putting the cart in front of the horse

That 252 needs some avionics and a new interior before any engine upgrade. Best of luck on the "deal".

[Parker_Woodruff]

Quote: fantom

Parker...you're putting the cart in front of the horse

That 252 needs some avionics and a new interior before any engine upgrade. Best of luck on the "deal".

[MooneyMitch]

A little birdie says Parker may be acquiring a 252!!!  Is that true??

[Parker_Woodruff]

Quote: Mitch

A little birdie says Parker may be acquiring a 252!!!  Is that true??

[MooneyMitch]

That's just really exciting!!!  Wowie!!!

[KLRDMD]

Quote: Parker_Woodruff

[KLRDMD]

Quote: fantom

That 252 needs some avionics and a new interior before any engine upgrade. 

[fantom]

Copy that, Ken.

The interior photo's don't do it justice then, and while the panel is OK "as is", knowing Parker's love of the latest glass gizmo's, I gotta believe some of the older avionics you checked out will be on the market soon. ;-)

[Parker_Woodruff]

Quote: fantom

Copy that, Ken.

The interior photo's don't do it justice then, and while the panel is OK "as is", knowing Parker's love of the latest glass gizmo's, I gotta believe some of the older avionics you checked out will be on the market soon. ;-)

[jackn]

Parker, I have the 252/encore conversion. I was off last week sailing the high seas, or I would have given my 2 cents. Mine was already converted when I bought her. Any help, let me know. I don't believe you can upgrade an MB to an SB easily. The SB may need beefier internals to get the extra 10 hp rating.I may be wrong, check with TCM. You can get the conversion drawing from Mooney.

I am thinking of selling my Encore to go to a Bravo w/FIKI. I know this kind of late for you, but if things change, let me know.

[Parker_Woodruff]

After talking with Don Maxwell this week, it's a "GO".

We've acquired all the parts (one control counterweight is being made by Mooney).  It's really not a scary mod; you just send out a few easy-to-remove engine parts out to Continental, put some different control weights on, change/modify the prop governor.

The expensive part is going to be modifying the brake system - about $3000 parts & labor is my guess.

All said and done, it appears it's a mod that can be accomplished for $6000-$8000.  Once it's done and I have the exact figure, I'll let yall know.  The number could significantly inflate itself if I get a JPI 930.

[kortopates]

Keep us posted about it - as you're beeting me to it

I was quoted over $4K for the brake parts kits a while back, plus a 6 week wait to pull the parts together. Will be curious to hear what you experience.

[Parker_Woodruff]

Quote: kortopates

Keep us posted about it - as you're beeting me to it

I was quoted over $4K for the brake parts kits a while back, plus a 6 week wait to pull the parts together. Will be curious to hear what you experience.

[KSMooniac]

Good luck!  Sounds like a bargain to me for the extra utility.

[kortopates]

I think what slowed me down was that the brake drawing listed mostly Mooney parts in addtion to the obvious cleveland/parker brakes assembly and cylinders. But the only Mooney part I can recall for sure now is the gear door, but I assume many others like perhaps a shuttle valve/parking brake. But you've spiked my interest up again and I'll have to review the list. It would be great too if it turns out many of those items on the drawing aren't necessary to replace.

 

[ChrisShopperly]

Hello guys!  I just joined MooneySpace and noticed this discussion.  I am currently contemplating an overhaul of the MB1 on my 1987 252 and am interested in the Encore/SB conversion process.  I understand that there may be a set of drawings and a list of requirements from Mooney to accomplish this change.  Does anyone have this material?

Thanks in advance for your help!

[kortopates]

Yes, there are specific airframe drawings for your serial number range and whether you intend to modify your existing MB engine to the SB configuration or whether you intend to remove your MB and install a SB engine (such as at overhaul time). Plus there is a separate drawing to retrofit the dual puck/cylinder brakes(drawing 94006). The specific drawings you need can be ordered from Mooney through your MSC at a pretty modest price (about $40).

[ChrisShopperly]

Thanks Paul!