PT20J

I like mine so much I just bought their manual towbar to keep in the plane. It has the same nose wheel lock mechanism and telescopes so you can see where you’re going when pushing. I also like the large handles that are welded at the correct angle.

Yes, but wait till the batteries need replacing. Priced golf cart batteries lately?

Low CHTs shouldn't be a problem unless due to running at very low power. Glazing is usually a break in issue, but it might happen if the engine were consistently run at very low power. Glazing is caused when the combustion pressures are too low to seal the rings properly and hot combustion gasses leak past the rings and bake the oil on the cylinder walls. I'd investigate further to determine the source of the problem. A borescope and compression test are good places to start. Glazing should be evident in a borescope inspection if it's present. Is there a lot of oil on the belly? If the rings are leaky, combustion gasses pressurize the crankcase and oil usually gets forced out the breather. Skip

I like SS screws and use them on the belly inspection plates. When I remove a plate, I put the screws in a zip lock bag and tape it to the plate - saves a lot of time searching for missing screws. I spray a little WD-40 in the bag so the screws are lubed when I put everything back together. Never had a galling or corrosion problem and they come out next year with no hassle. Skip

John Deakin ran a TN Bonanza and wrote a lot of articles about LOP operations. They’re on Avweb.

M20Js have an electric gauge and transducer. It could be a measurement issue, since both pumps have about the same pressure and the engine runs fine. The way a good A&P would troubleshoot it would be to connect a known accurate gauge in the line and see what it reads. Skip

Call Jimmy at All American - he’s been valuing Mooneys for 25 years and has sold hundreds of them. And, he’s fair and honest (that’s why he’s been in the business so long). Skip

You’ve got to ask, why is it cheap? Remember that the seller knows more than you will know until a couple of annuals have been completed. The pre-buy will only catch (hopefully) show stoppers. Lots of little things add up. Mooney isn’t really making many airplanes. They are mostly selling parts for old ones. Parts are thus expensive. I think Mike Busch’s advice to buy the newest, cleanest, lowest time airframe you can find/afford is sound advice for lowest total cost of ownership. Skip

I remember it being there also. But, now that it’s certified, the graph is gone. I wrote the following to Surefly: I am interested in replacing the Slick impulse-coupled magneto on a Lycoming IO-360-A3B6 installed on an M20J with a SIM.Can you supply the timing advance schedule (as a function of MAP and rpm) for the SIM?I note the SIM uses a wasted spark design. What is effect on spark plug life? Do you recommend iridium plugs?Do you have any data showing performance or fuel efficiency improvements for my engine? The reply was: We do not recommend any spark plugs outside your standard manufacturers specs. Your engine is approved for both fixed and variable timing. The fuel efficiency and improvements are based on so many variables that we can’t give any definitive numbers. The wasted spark system should not affect the life of a standard plug. They did not send the advance curve. I asked again for it, but have not received a reply. I’ll share it if I ever get it. Skip

Where did you find the curve on Surefly’s website? I looked all over and couldn’t find it. I emailed them (twice) asking for it but so far no dice. Interesting that Lycoming’s rebranded version is set for fixed timing. Skip

Now that you’ve found the pitot drain, you can look for the static drain. (Hint: it’s near the static ports). Cherokees have them inside the cabin at the left wing root. Skip

I did some research on the bearings recently for another thread. They are PN3A needle bearings. They are not sealed and the Mooney maintenance manual calls for oil. 3-in-1 or similar will work.

For resale, best option is to mimic the latest factory paint scheme. Makes the plane seem newer. If you get too crazy, it may only appeal to you. On the other hand, Mooneys are always going to be a seller’s market buy when the economy is good because they don’t make many new ones and they don’t make mid- and short-bodies at all any more and a lot of the ones out there are, ah, shall we say undesirable. All airplanes go buyer’s market when the economy tanks (which is probably overdue). Curious: Has anyone who has painted a plane a dark color noticed any difference in cabin temps from white? Skip

Seems to give a reasonable number in this case, but I’m curious about the derivation.

Welcome aboard. Did you fly with Amelia? Did she fall asleep? Skip

This is precisely why Don Maxwell told me he never became a repair station. Skip

Pretty good discussion of the Surefly timing advance here http://www.vansairforce.com/community/showthread.php?p=1350922 Skip

Mike Busch covers this particularly well in his Sept 2019 column in AOPA PILOT. ICA compliance (annual or otherwise) is not required for part 91 operators of small non-turbine airplanes unless the ICA contains FAA-approved airworthiness limitations. This does not mean that some ICAs are not a good idea. But as the operator, you bear the responsibility to decide. Skip

I'm interested in what others are seeing for takeoff fuel flow at sea level in an M20J. I can't find a specification for this from Lycoming. The Operator's manual shows 94 pph (15.7 gph) at 100% power, best power mixture (not full rich). For the HIO-360 it shows a suggested high limit of 105 pph (17.5 gph) for 100% power. The test stand data that came with my rebuilt IO-360-A3B6 shows 92.83 pph at an airflow of 1000 pph. Max power generated an airflow of 1118.5 pph but fuel flow was not recorded at this condition. Assuming linearity and extrapolating, this would be 103.8 pph (17.3 gph) at 100% power. So, my guess is that the fuel flow should be between 17 and 17.5 gph. Skip

We probably all know that the magneto ignition system reverses polarity every firing. That's why we rotate plugs. Since the spark jumps from cathode to anode, taking a bit of metal with it, if we didn't rotate the plugs the ground electrodes would erode on half the plugs and the center electrode would erode on the other half. Rotating (in an engine with an even number of cylinders, i.e., non-radials) evens out the wear. https://www.themagnetoguys.co.uk/spark-polarity A bit of research shows that wasted spark systems for automobiles tended to use plugs with platinum on both electrodes because of alternating polarity and twice the number of sparks. https://en.wikipedia.org/wiki/Wasted_spark https://shop.advanceautoparts.com/r/advice/car-maintenance/the-differences-between-spark-plugs Does this apply to airplane engines and Surefly ignition? Maybe... Massive aviation spark plugs have much larger electrodes than automotive plugs -- maybe they can take the extra sparks in stride. Also, the wasted spark occurs on the exhaust stroke with higher gas temperatures and lower cylinder pressures, so the plug fires easier with much less energy in the spark to move metal. If I were installing a Surefly and had serviceable massives, I'd keep them so that I would only be changing one component of the ignition system. Then I could determine what advantages Surefly might have. When the plugs wore out, I'd change to fine wires. Skip

Since it's a wasted spark system, the plugs fire twice as often (two plugs always fire at the same time -- the "wasted" one fires during an exhaust stroke). I asked if this would wear the plugs out faster and Surefly said no, but I wonder if it might not be better to use fine wire plugs. Skip

The procedure calls for calibration both clean and flaps/gear down. There are two pointers, one for each calibration setting. Mine (installed by a defunct avionics shop for the previous owner) is way out of calibration; normal approach is way into the cross-hatch stall warning area. Sooner or later I will try to correct it, but the display on a single display EFD1000 is so small that it doesn't really seem that useful to me. Skip

I talked to LASAR, Top Gun and Maxwell when planning my conversion. By far, Maxwell had done the most conversions. Don was the only one to give me a complete and accurate list of parts required. When I asked him how he did that, he said, in his east Texan way, "It's all in the IPC." And, he's right. All the part numbers are in the IPC if you read it carefully. The problem is that there are no drawings for the A3B6 installation, so you have to figure out a few things for yourself, like rotating the oil cooler 180 degrees. By far the most confusing part from reading many posts is the prop governor installation. You need to get the new bracket, clamps, bellcrank and spacer. I detailed it pretty well toward the end of this thread: Skip

If the relays are grossly underrated, I would expect most of them to fail in service. But most seem to be trouble free for many, many years/hours. A failure within 200 hours of 1-4 hour flights is a failure after maybe 100 operations of the relay. Something else is probably going on.

According to the M20J IPC, the relays changed part number when the preselect feature was added. Not sure if that has any bearing or not. I’ve also seen a thread here somewhere where someone noted that one of the relays can chatter if the flaps are in takeoff position and then pressure applied as might happen with an air load if the microswitches are not set up perfectly. Skip