M20J IO-360-A3B6 Conversion Experience

[carusoam]

Nicely written piece, PT...

Any of that work leave you nervous about getting the project completed?

+1 for the plug for MSer @GEE-BEE

Best regards,

-a-

[PT20J]

No, actually it all went pretty smoothly. I did a lot of research beforehand and had all the parts ready to go. I owe a lot to those on the forum that went before me as their insights were very helpful. For instance, we would not have thought to reinstall the right magneto grounding link on the ignition switch if it hadn't been mentioned here. My IA owns a M20C and has done engine changes, but never on a M20J. We worked on it together and his experience and my research made a good combination with no real surprises.  Even with both of us working on it, it took ten full days to hang the new engine.

[PT20J]

One more thing: How to connect the p-lead shields on the Slick mags?  My AI and I connected the shields to the ground terminals on the mags. Recently, I was chasing down another issue and found differing opinions on line about how the shields should be grounded. None other than the highly respected Jim Schwaner (formerly of Sacramento Sky Ranch) advocated connecting both ends to ground as we did. This is usually a bad idea as it can create a ground loop. Careful study of the wiring diagram for my s/n shows that Mooney grounded the p-lead shield at the ignition switch and not at the mags. The shields are connected to the GND terminal on the ignition switch, and the GND terminal is in turn connected to airframe ground.

I asked Joe Logie at Champion for Slick's recommendation and he said not to ground at the magneto end. So, I'm going to remove the connection at the mag end of the p-leads next time I have the cowling off.

Skip

[rotorman]

The purpose of this post is to add to the body of knowledge on the A3B6 conversion, specifically the governor bracket installation. Skip provided the drawing below. The instruction assumes the use of the same bracket parts called out in this thread along with a same vertical orientation of the bracket itself. However that 660235-001 bracket is no longer available. These are the part numbers from the above post thread.

• 660017-003 Prop cable clamp half 

• 660017-005 Prop cable clamp half

• 660235-001 prop cable bracket

• 660235-003 governor bell-crank

 

On my installation, bracket # 660117-000 was used. I don't have the part numbers for the rest of the kit.  Dan at Lasar said that when they use this bracket the orientation is horizontal similar to the below drawing for the A3B6D installation.  Also from the drawing below 50b is not used. 

 

 

Edited September 26, 2021 by rotorman
Corrected bracket part number

[blankc]

Does anyone have the installation text of ModWork's STC SA250GL so that I can double check to make sure my governor is correct? My rigging is still what the parts book shows for A3B6D and presumably A1A, but I have the STC for the A3B6 that was installed in 1995. I just did an overhaul and want to verify that all my components are correct. I have a C290D5-J/T24, which is not even in the parts book that I have. It works as is and I get 2700 RPM.

[rotorman]

I did the A36B conversion in late 2020. After taking delivery of the rebuilt engine, I found that the wrong governor was installed. It's a long story as to how I arrived at that conclusion but the shop agreed and in consultation with the prop shop replaced it with the correct one. I now have a DC29001-F/T22. 

Edited April 16, 2022 by rotorman
Corrected gov part number I am using.

[mcarterak]

LASAR told me that the ModWorks STC airplanes had the C290D5-J/T24. That's what was installed in my plane, but I was NOT getting 2700 rpm, only about 2610 even in a dive, and it was out of adjustment. The DC290D1/T22 is on the TCDS for the A3B6 and that is what I currently am having installed.  

[Martin S.]

On 7/13/2015 at 3:20 AM, dhc said:

06: That new prop governor arm--correct orientation, and how to rig

 

The –A3B6 installation requires a new prop cable rigging arm, which must be purchased from Mooney. These are the P/N’s:

 

• 660017-003 Prop cable clamp half

• 660017-005 Prop cable clamp half

• 660235-001 prop cable bracket

• 660235-003 governor bell-crank

 

And the governing chapter in the Mooney Parts Manual is 76-00-01.

 

The proper installation of these parts is completely opaque: neither the Parts nor Service manual contain any drawings to provide proper guidance. Worse, on Mooneyspace, there is an often-cited post with an ABSOLUTELY WRONG installation of the both the bracket and the governor bell-crank.

 

I am including both the wrong photos (properly annotated) and correct ones in this post. Note:

1. The proper orientation of the cable bracket relative to the engine
2. The proper layout of the two clamp halves (“thin one on top”)
3. The proper position of the prop cable metal collar in the clamp halves

Proper rigging also requires that full prop speed be attained with cable all the way in (with sufficient “cushion”), and the degree of freedom used here for this model of prop governor (McCauley DC290D1-F/T22) is that the center part of the assembly rotates freely when the 6 allen head screws are loosened. Since the position of the center part is at an arbitrary clock angle when the unit is newly acquired, it is good to scribe the final rigged clock angle for future use, as the photo shows.

 

 

Evening everybody,

 

this post seems very interesting to me, but I cannot open any of the files. Does anyone know how to access the files of dhc's conversion story?

 

Greets,

 

Martin

[Martin S.]

On 7/13/2015 at 3:20 AM, dhc said:

06: That new prop governor arm--correct orientation, and how to rig

 

The –A3B6 installation requires a new prop cable rigging arm, which must be purchased from Mooney. These are the P/N’s:

 

• 660017-003 Prop cable clamp half

• 660017-005 Prop cable clamp half

• 660235-001 prop cable bracket

• 660235-003 governor bell-crank

 

And the governing chapter in the Mooney Parts Manual is 76-00-01.

 

The proper installation of these parts is completely opaque: neither the Parts nor Service manual contain any drawings to provide proper guidance. Worse, on Mooneyspace, there is an often-cited post with an ABSOLUTELY WRONG installation of the both the bracket and the governor bell-crank.

 

I am including both the wrong photos (properly annotated) and correct ones in this post. Note:

1. The proper orientation of the cable bracket relative to the engine
2. The proper layout of the two clamp halves (“thin one on top”)
3. The proper position of the prop cable metal collar in the clamp halves

Proper rigging also requires that full prop speed be attained with cable all the way in (with sufficient “cushion”), and the degree of freedom used here for this model of prop governor (McCauley DC290D1-F/T22) is that the center part of the assembly rotates freely when the 6 allen head screws are loosened. Since the position of the center part is at an arbitrary clock angle when the unit is newly acquired, it is good to scribe the final rigged clock angle for future use, as the photo shows.

 

 

Evening everybody,

 

this post seems very interesting to me, but I cannot open any of the files. Does anyone know how to access the files of dhc's conversion story?

 

Greets,

 

Martin

[PT20J]

I think a lot of stuff got deleted when the server ran out of storage space.

[Martin S.]

32 minutes ago, PT20J said:

I think a lot of stuff got deleted when the server ran out of storage space.

Too bad - these infos seem very valuable.

[PT20J]

Yes, there was a lot of good info in that thread. But if you have specific questions, there are a number of us that have been through it and can probably help out.

[OR75]

2 hours ago, Martin S. said:

Evening everybody,

 

this post seems very interesting to me, but I cannot open any of the files. Does anyone know how to access the files of dhc's conversion story?

 

Greets,

 

Martin

I made a pdf document with the pictures / info that used to be in this thread in preparation of my still to happen overhaul (although in my case it will be an IO-390 but the accessories panel is the same as the IO-360-A3B6. ).  happy to share it with you if you want it. Pm me if you do. 

[OR75]

since some asked if I could send a copy of the pdf I created a while ago using the info in these post (with the pictures ) , I am including it for the MS community. Thanks to the OPer

IO-360-A3B6 Installation.pdf

[EricJ]

9 hours ago, OR75 said:

since some asked if I could send a copy of the pdf I created a while ago using the info in these post (with the pictures ) , I am including it for the MS community. Thanks to the OPer

IO-360-A3B6 Installation.pdf 2.17 MB · 8 downloads

Very nice!   Thanks for that!