Ignition Leads M20E

[BVUICICH]

 I recently purchased a nice m20e with all the mods and nice radios. Last weekend I decided to  uncowl the beast as I cannot leave anything alone. I found a few items that needed some general tinkering with, but everything looked average for its age. One item  that appeared to need some attention were the Ignition leads(they appear to be the original one's). I'm sure the leads do not need replacement at this time, but I think it would be a good idea. Does anyone know of a good source for new ones that will not break the bank?

[Bob_Belville]

Buddie, you'll need to know what mags, timing, plugs (5/8" or 3/4") you have. Here's a reference manual from Chief Aircraft ... Aircraft Spruce is also a popular supplier... 

http://www.chiefaircraft.com/pdf/L-1318G-58-application.pdf

[BVUICICH]

THANKS A MILLION!!!!

[bonal]

Welcome BV we definitely need to know more to help you spend your money. Also keep in mind the old adage if it ain't broke don't fix it. And of course post some pics of your new pride and joy

[Marauder]

 I recently purchased a nice m20e with all the mods and nice radios. Last weekend I decided to  uncowl the beast as I cannot leave anything alone. I found a few items that needed some general tinkering with, but everything looked average for its age. One item  that appeared to need some attention were the Ignition leads(they appear to be the original one's). I'm sure the leads do not need replacement at this time, but I think it would be a good idea. Does anyone know of a good source for new ones that will not break the bank?

Let us know what harness you need. Some of us are hoarders.


Sent from my iPad using Tapatalk Pro

[ArtVandelay]

Buddie, you'll need to know what mags, timing, plugs (5/8" or 3/4") you have. Here's a reference manual from Chief Aircraft ... Aircraft Spruce is also a popular supplier... 
http://www.chiefaircraft.com/pdf/L-1318G-58-application.pdf

Timing? How does timing affect the ignition leads?

[Bob_Belville]

I don't know, the Chief Aircraft chart lists 20 BTDC and 25 BTDC separately and has 3 different mag pair for each but it looks like there are just 3 harnesses for the 3 mags combos. 

Engine Complete LH RH Engine - Model (Degree°, HP) LH Harness RH Harness Harness Notes

IO-360-A1A (20°,200HP) M4004 M2989 M2990 X 2, 3

IO-360-A1A (20°,200HP) M2402 M2403 M2404 X 2, 3

IO-360-A1A (20°,200HP) M2365 M2017 M2016 X 2, 3

IO-360-A1A (25°,200HP) M4004 M2989 M2990 X 2, 3

IO-360-A1A (25°,200HP) M2402 M2403 M2404 X 2, 3

IO-360-A1A (25°,200HP) M2365 M2017 M2016 X 2, 3

IO-360-A1B (20°,200HP) M4012 M4019 M4020 X 2, 3

IO-360-A1B (20°,200HP) M4004 M2989 M2990 X 2, 3

IO-360-A1B (20°,200HP) M4006 M2983 M2984 X 2, 3

IO-360-A1B (20°,200HP) M4007 M2977 M2976 X 2, 3

IO-360-A1B (20°,200HP) M2364 M1980 M1975 X 2, 3

IO-360-A1B (20°,200HP) M2365 M2017 M2016 X 2, 3

IO-360-A1B (25°,200HP) M4012 M4019 M4020 X 2, 3
 

[RLCarter]

Timing is odd, or so I think....

 

[Bob_Belville]

9 hours ago, RLCarter said:

Timing is odd, or so I think....

 

Makes sense. My main point is that "M20E" or even "IO360A1A" is not enough information to be sure you're getting the right mags, plugs, or ignition harnesses.    

[BVUICICH]

 M20E Fuel Pressure. Thank you so much for the info. I will uncowl this weekend and get the numbers off the mags. Well they say don't borrow trouble , Well I guess I did! I have only have about 12 hrs. on the plane since I picked it up in early January. I'm located at a high elevation airport with somewhat high density altitude(ksrr). The other day I decided to take one of my friends up for a casual ride to demonstrate the speed and handling of my steed. So we climbed to 10.0 and trimmed the prop to 2500. The OAT was about 48F. everything seemed fine until I looked at the fuel pressure/ manifold gauge. The fuel was reading right at the bottom of the green area, I'm guessing about 15lbs.Now given my nature I'm in full blown panic mode thinking my mechanical pump is almost done. I checked several of the blogs and found I need to check the snuffer for blockage and. possibly the fuel strainer( The one I cannot find). Ok back to the original problem, do I have a problem? and if I do am I on the right track. P.S. EGT and Fuel flow was steady.

[ArtVandelay]

. The fuel was reading right at the bottom of the green area, I'm guessing about 15lbs.Now given my nature I'm in full blown panic mode thinking my mechanical pump is almost done. I checked several of the blogs and found I need to check the snuffer for blockage and. possibly the fuel strainer( The one I cannot find). Ok back to the original problem, do I have a problem? and if I do am I on the right track. P.S. EGT and Fuel flow was steady.

What happen when you turn on the electric boost pump?

[Shadrach]

An original ignition harness on even the most recent E model would be ancient (41 years old) by harness standards. What does your harness look like? A 10 to 12 yr old harness doesn't owe you a thing. A 40 year old harness is on borrowed time man times over.

[BVUICICH]

Nothing changed, pressure remained the same. The pump does work on boost but not higher than 15 maybe 16. Starts fine. I disconnected the fuel line at the firewall and I did have pressure. Not sure how much? 

[ArtVandelay]

Could be a gauge or sensor issue.

[mike_elliott]

12 hours ago, BVUICICH said:

 Thank you so much for the info. I will uncowl this weekend and get the numbers off the mags. Well they say don't borrow trouble , Well I guess I did! I have only have about 12 hrs. on the plane since I picked it up in early January. I'm located at a high elevation airport with somewhat high density altitude(ksrr). The other day I decided to take one of my friends up for a casual ride to demonstrate the speed and handling of my steed. So we climbed to 10.0 and trimmed the prop to 2500. The OAT was about 48F. everything seemed fine until I looked at the fuel pressure/ manifold gauge. The fuel was reading right at the bottom of the green area, I'm guessing about 15lbs.Now given my nature I'm in full blown panic mode thinking my mechanical pump is almost done. I checked several of the blogs and found I need to check the snuffer for blockage and. possibly the fuel strainer( The one I cannot find). Ok back to the original problem, do I have a problem? and if I do am I on the right track. P.S. EGT and Fuel flow was steady.

You will have 2 strainers, one on the fuel selector and a finger strainer on the fuel servo. If the fuel selector is leaking air into the system, this would cause it, as will small holes in the diaphragm of the mech. fuel pump. While the fuel selector is a simple device, it is one of those "ill kill you if you don't put me back together just right" items and should be left to someone who has done them before and knows exactly what they are doing, and not the A&P in the next hanger who has never seen one before but is qualified to legally kill you. I had a similar problem a decade or 2 ago in my F model, it was the fuel pump.

[N201MKTurbo]

There is also the screen after the electric fuel pump.

[BVUICICH]

I think at this point I will go ahead and replace the pump( cheap insurance). It looks like a real bear to replace, but not impossible. Do you or anyone have a good source for a new pump. Not sure if I should go new or rebuilt?

[Shadrach]

50 minutes ago, BVUICICH said:

I think at this point I will go ahead and replace the pump( cheap insurance). It looks like a real bear to replace, but not impossible. Do you or anyone have a good source for a new pump. Not sure if I should go new or rebuilt?

1) I don't think you should replace the pump, perhaps speak with an A&P about the problem

2) Just throwing parts at an issue is rarely sound maintenance policy, it's usually a last resort that gives less than stellar results.  It is probably a better idea to find out what is causing the problem.

3) Replacing a perfectly serviceable and well functioning part is not "cheap insurance". It's introducing a variable (maintenance) into a system that all evidence suggests is not the problem. 

The mechanical pump is statistically one of the most reliable accessories on the aircraft.  Moreover, you've stated that turning on the boost pump does not change the pressure reading.  Why on earth would you dig into the pump?  

Just from what you've said so far, I would start with what is easiest...verifying the gauge is correct.  I would then start tracing back from there.  The boost pump alone ought to be able to hold nearly 20 psi, the engine driven pump should produce 23-24 psi in cruise.

 

[Andy95W]

Do what you want, but if you are only getting 16 psi with either the engine driven or electric fuel pumps, you've got a different problem.  But your shop will love you for being very thorough.

[BVUICICH]

1. Thank all of you for your valuable input! I'm blown away with the responses, great info.

2.Thinking back about this problem, it showed up overnight. I was thinking about my own experiences with an automotive mechanical fuel pump. If failed slowly, starting with long crank cycles. NOT THE CASE HERE

3. This weekend I'm going to remove the gauge and if I'm lucky(according to the parts manual) I will remove the snuffer and check for an obstruction. I think I have a access to an automotive gauge to verify the pressure. If I can get the correct fittings without 20 trips to town.

4. The parts manual shows the snuffer or what ever its called to be attached the back of the gauge.

5.  I will  keep you posted.

6. Any ideas are welcome THANK YOU

[N201MKTurbo]

If your fuel pressure gets below the green your engine will stumble. If your pressure indicates below the green and your engine is still running ok I would suspect the gauge.

[BVUICICH]

It dropped below the green a few times and still ran fine.   Thanks

[flyntgr1]

10 hours ago, N201MKTurbo said:

There is also the screen after the electric fuel pump.

Is that a screen?  I thought that was a filter that was installed as part of an AD note.

[N201MKTurbo]

18 minutes ago, flyntgr1 said:

Is that a screen?  I thought that was a filter that was installed as part of an AD note.

Yes and yes. It is a screen. It was put there to catch the parts of the fuel pump when it eventually comes apart. It should be cleaned every annual. It only takes a few minutes.

[carusoam]

By the way...

'Snubber' a small orifice in line with or as part of the pressure gauge.  It is calibrated to remove the pressure oscillation of the fuel pump and whatever else oscillates the fuel's pressure...

The MP often gets one as well. The MP of the 60's Mooney's had a tiny hole in the aluminum line connected to the intake.  This also kept fuel from being sucked towards the gauge during the engine shutdown.

Best regards,

-a-