PT20J

One of my JPI EGT probes is getting wonky and the wiring and connections check good. These probes have over 1500 hours on them (JPI claims 600-1000 hour life expectancy) so I'm going to replace them all. The original installer bundled the EGT/CHT wiring with the ignition wires which is not recommended by JPI, although I've never noticed a problem. But, since I am replacing them, I'd like to clean up the installation. Anyone have pictures of how your IO-360 EGT/CHT wires are routed to the cylinders?

3” extensions should be available from Mooney through any Mooney Service Center. You need two; one for each pilot’s pedal.

I would run a tank dry, let it sit for a day and then remove the sump drain and drain out all the unuseable fuel which will get the tank as clean as you can get it without flushing it. Then you can see if it comes back.

What glue did you use?

It's unlikely it left the factory that way, so something has changed. The amount of adjustment to set the preload is pretty small. All three wheels are rigidly connected together. Maybe the problem is the other main gear.

A few points to consider: 1. Since the ammeter shows a positive indication (no matter what the value) the charging system is working. What is the bus voltage? 2. The air conditioner compressor is engine driven not electrically driven according to the M20R manual. 3. The annunciator flashes to indicate a low voltage (charging system failure) or it is steady on to indicate that the overvoltage protection circuit has tripped (usually a voltage regulator failure). Dim is not a valid indication. Since this only happens when the air conditioner is on, perhaps something is amiss with the annunciator or the air conditioner. The service and maintenance manual has procedures for checking out the electrical system and the air conditioner. You might call the manufacturer of the annunciator to inquire what would cause a dim indication. https://www.internationalavionics.com/

I think Byron @jetdriven said he changed his.

Dukes Actuators. For M20J: S/N 24-0001 - 0083, 0085 - 0377 according to the IPC. Later Js had Eaton or Plessey actuators with the somewhat infamous noback spring.

It’s a vacuum formed blank panel There’s nothing behind it. It can be used to mount a variety of options as illustrated in the above posts. Mine used to have an EDM 700 there and that instrument is pretty deep.

I had the same experience as Eric. I finally tracked the debris down to paint on the wing around the fuel caps chipping off and falling into the tank. Check that it’s not leaking from the sender screws. I’ve had a couple of those seep. You can remove them one at a time and coat the threads with EZ Turn or non-hardening Permatex and retorque them gently (spec. is 20-25 in-lbs.)

I think a lot of people have had them weld repaired.

Yes, but the torque plates are for use if the cylinders are going to be left off for a while. Obviously you have to undue all the fasteners to remove the cylinders and install the plates. So, if torque is in question, why not loosen everything and proceed as if you were installing all new cylinders? The through studs will only be loose for a few minutes.

I see your point. I don’t think just checking that the wrench clicks before the nut moves means the torque is correct because the breakaway torque is going to be higher than the running torque, but I guess it would uncover anything that was grossly under torqued. I guess if it were mine I might consult with Lycoming about the best course of action.

Rich, to get an accurate torque, would it be best to loosen everything and start over?

Lacing is most commonly used for wire bundles.

https://gama.aero/wp-content/uploads/2023ShipmentReport-03-08.pdf

Looks like a typo in the SB. The IPC calls for 5491. I can’t imagine it matters as long as you get a good fit with some slippery tape. We used some UHMW tape we had on hand.

JPI claims that its EGT probes last about 600-1000 hours. Mine have been in service for about 1500 hours. I'm wondering what symptoms others have seen that indicate imminent probe failure.

The thin plastic with the foam core was probably BA-189-139. It is softer than the T-9088. But the problem with it is that the foam deteriorates over time and the seal loses its resiliency. Brown Aircraft discontinued it (I called them) and Mooney switched to the T-9088. The T-9088 works but the positioning is critical. The bottom is the hardest to get right because there are no latches or pins to hold the door tightly closed, the door hold-open arm is located on the bottom edge, and the curvature of the door frame corners does not match the curvature of the door. I had to remove the right seat and lay inside with the door closed and use a flashlight and a Sharpie to mark the proper location for the seal on the bottom. Along the top and sides, the centerline of the bulb should be placed on the line of rivets fastening the inner and outer door panels together. EDIT: A trick Don Maxwell uses if there is still an area (usually along the bottom) where the seal isn't tight enough even though it is positioned properly is to cut off a piece of the flat "tail" from a left over piece and glue that under the door seal to shim it a bit. I had to use that in one spot and it worked great.

The breather tube on my M20J is stiff and I asked Frank Crawford what it was made of and he looked it up and the drawing says poly vinyl. It would seem that Tygon might be a better choice on the older airplanes as well.

I've tried it. I had a discussion long ago with aeronautical engineer and handling qualities consultant Roger Hoh who pointed out that not all airplanes wind up tighter and tighter and faster and faster until making a smoking hole in the ground. Spiral divergence is caused by the directional stability being greater than than the lateral stability. But the longitudinal stability can be a factor also. Normally a Mooney phughoid lasts about 2-1/2 cycles. If you get the airspeed right (trimmed to about maneuvering speed) and the airplane is well rigged, I've let a spiral start power off and watched it stabilize in about a 45-degree bank and get almost to redline before the nose started up and then it got almost to stall before the nose came back down and then did this another time and a half with lower amplitude each time until it finally stabilized at trim speed in a 45 degree descending turn. This was long ago in my 1978 M20J. I haven't tried it in my 94 J.

It took me a few tries to learn how to do this. The placement of the seal on the door is critical. The gap between the door and the fuselage is not uniform. If you use the proper 3M yellow adhesive, there is an hour or so open time to reposition the seal. Don't use too much adhesive -- a thin coat on both surfaces is all you need and be sure to clean the seal and door with denatured alcohol first. After positioning, I close the door on a sheet of printer paper. If the seal is positioned correctly, the door will latch but take some pressure to close and the paper cannot be pulled out without tearing. If it won't shut or the paper is loose you can reposition the seal. If you use the Brown T-9088 seal and shut the door and leave it for a couple of days it will take a set and the door will be much easier to close thereafter and it won't leak.

M20C checklist.pdf

The up limit switch is in a fixed bracket and the adjustment is on the little paddle on the push pull tube, so I didn't have to worry about the adjustment.

The truss and spindle should last darn near forever if properly lubricated at regular intervals. The leg wears on the bottom plate where the weight of the airplane rests on it. The later horns are hollow and should be filled with grease. I suspect that a lot are under lubricated. I don't see why a steering horn can not be rebuilt in the field.