1970 M20C Panel Upgrade

[tcal780]

12 hours ago, ragedracer1977 said:

I believe that’s normal behavior on a no start and a bendix.  The faster speed of the ring gear when the engine starts kicks the gear off.  I’m not 100% on that, but I’d look into it before you spend money.

 The no start is almost assuredly a p lead issue.  I’d triple check your key wiring.  First thing I would do… key off - stay away from the prop! If you wired it backwards, the mags might be hot! Check if your p leads have continuity to ground.  If they don’t, they’re hot.  If they do, go turn the key to “on” or “run” and check continuity again.  If they’re still grounded, it’s a wiring issue.  I’ve seen 3 guys at the field with ignition switches wired incorrectly. 

Thanks for this. From what I've read, since the gear engages, the bendix drive is likely still good and needs a cleaning, unless the spring is shot. Either way, there's enough justification for me to replace it with a new one that also gives me 10lbs back of useable weight.

Next opportunity I get, I'll check those connections at the ignition switch.

 

[EricJ]

On 12/1/2024 at 10:04 PM, ragedracer1977 said:

I believe that’s normal behavior on a no start and a bendix.  The faster speed of the ring gear when the engine starts kicks the gear off.  I’m not 100% on that, but I’d look into it before you spend money.

That's correct.   The starter motor spinning engages the starter gear with the ring, and the engine starting disengages it.   If the starter was engaged and the engine hasn't started since, it would be expected that the starter gear would be engaged with the flywheel ring.

Edit:   This is for the stock starter.   I think the SkyTec uses a solenoid that disengages the gear.

 

[tcal780]

I verified the ignition wiring was correct and the SOS is functioning properly. I also took the opportunity to replace the ignition harnesses which really needed to be done.

Yesterday, I got the plane out of the hanger for another attempt and it fired right up! I don't think it took more than one revolution with the starter.

My only conclusion is that I did not give it enough fuel on the last attempt. This time, I ran the boost pump with the throttle closed until the fuel flow showed 0GPH. Then, followed a normal, cold start procedure.

Anyway, while the old starter was still serviceable, I'm super happy with the SkyTec and glad to have installed it.

[Hank]

3 hours ago, tcal780 said:

My only conclusion is that I did not give it enough fuel on the last attempt. This time, I ran the boost pump with the throttle closed until the fuel flow showed 0GPH. Then, followed a normal, cold start procedure.

When cranking my 1970 C, after turning on the Master Switch, I run the fuel pump until fuel pressure stabilizes, then turn the pump off. Mixture rich, pump the throttle a few times (half a dozen or so in winter, once or twice in summer).

When it's cold, fuel in the carb evaporates slower, so I'll wind and set the yoke clock and put on my headset before turning the key. She usually fires right up if preheated, but if not, hold the key and pump the throttle while cranking and it will fire.

[Ventus4]

Nice panel,

Since I plan to do a very very similar work, do you have the cad (dxf or any other format) of the panel ?

Thank you a lot.

Andrea

 

[tcal780]

5 hours ago, Ventus4 said:

Nice panel,

Since I plan to do a very very similar work, do you have the cad (dxf or any other format) of the panel ?

Thank you a lot.

Andrea

 

Unfortunately, all I have is a PDF proof that was provided to me for final approval. It's not to scale, but if it would help, let me know and I'd be happy to send it.

[tcal780]

Radios and audio panel installed and tested.

Getting closer!

[Hank]

On 1/19/2025 at 7:20 PM, tcal780 said:

Radios and audio panel installed and tested.

Getting closer!

Wow! That looks great. But it would be difficult getting used to the switches and hear knob being down at the bottom . . .

[tcal780]

33 minutes ago, Hank said:

Wow! That looks great. But it would be difficult getting used to the switches and hear knob being down at the bottom . . .

Honestly, it'll probably take me more time to get used to the engine instruments being right in front of me. 

[Ventus4]

Sorry for my late answer tcal,

Thank you for the offer. Who made your panel ? I may contact them directly and ask.

Thank you and compliment for the result.

Andrea

 

[tcal780]

40 minutes ago, Ventus4 said:

Sorry for my late answer tcal,

Thank you for the offer. Who made your panel ? I may contact them directly and ask.

Thank you and compliment for the result.

Andrea

 

No problem and thanks. Superior Aircraft Components out of Hutto,TX made the panel. They were great to work with and I would recommend them but I'd be surprised if they hand over any dwg files.

[Sapphire1]

Do you have the dimmer assembly wiring diagram by any chance? My dimmer circuit has an issue but we cant find a diagram for it. Thanks

[tcal780]

Sorry, I don't have a wiring diagram for the original dimmer assembly.

[AndreiC]

3 hours ago, Sapphire1 said:

Do you have the dimmer assembly wiring diagram by any chance? My dimmer circuit has an issue but we cant find a diagram for it. Thanks

Are you looking for the original, factory dimmer electrical diagrams for a 1970 Mooney? I have them (there are two versions) somewhere, I can look them up. 

[Hank]

5 hours ago, Sapphire1 said:

Do you have the dimmer assembly wiring diagram by any chance? My dimmer circuit has an issue but we cant find a diagram for it. Thanks

 

1 hour ago, AndreiC said:

Are you looking for the original, factory dimmer electrical diagrams for a 1970 Mooney? I have them (there are two versions) somewhere, I can look them up. 

@Sapphire1, when the circuit board on mine blew, I had just come out of the clouds on a VOR-A approach over WV, and it caused a total electrical failure. My Mooney was down for several months because whatever blew up was completely gone, and no one could tell what it used to have been.

I eventually managed to find a replacement board, but no idea what I'll do the next time.

@AndreiC, can you post the drawings here? Or send them by PM, and shoot me a copy too. Thank you!

[Sapphire1]

I just lost lighting on engine instrument cluster, compass and overhead lighting. They were able to bypass the dimmer circuit to get the lights on, now they need to troubleshoot the dimmer control box. Maxwell states they repair them if my AP cant sort it out.

[Sapphire1]

13 hours ago, tcal780 said:

Sorry, I don't have a wiring diagram for the original dimmer assembly.

Thanks.

I love your panel!

[Sapphire1]

9 hours ago, Hank said:

 

@Sapphire1, when the circuit board on mine blew, I had just come out of the clouds on a VOR-A approach over WV, and it caused a total electrical failure. My Mooney was down for several months because whatever blew up was completely gone, and no one could tell what it used to have been.

I eventually managed to find a replacement board, but no idea what I'll do the next time.

@AndreiC, can you post the drawings here? Or send them by PM, and shoot me a copy too. Thank you!

Thanks. I sent them to my A/P for review.