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About PT20J

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    1994 M20J

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  1. They quoted me 9 weeks and it took 11-1/2. The real problem was communication. No one told me -- or Air Power that I bought the engine from -- that it was going to ship late. I had time reserved at the shop for the installation and had to keep rescheduling. The shop was very good about juggling, but it wasn't really very fair to them. I never could get a good ship date until I got the email that it had shipped. Then, the shipper agreed to call me to arrange a delivery time. Never got a call -- it just showed up one day. Moral is, it gets there when it gets there. Be careful unpacking it so you can reuse the packing to return the core. Skip
  2. The old Apple campus was located at 1 Infinite Loop, Cupertino, CA USA. An "infinite loop" is generally considered to be a programming error. Just sayin'. Skip
  3. Based on my experience, don't be surprised if it the ship date slips. The date the factory gives you is only an estimate. Mine slipped a couple of weeks and I didn't find out until they missed the ship date. But.. it's got roller tappets! Skip
  4. I installed a Lycoming rebuilt IO-360-A3B6 last October. Lycoming sent a bunch of service instructions and bulletins with the engine as well as a DVD. I found the break in procedure a bit confusing. Most of the information supplied is for a field overhaul. But with a rebuilt, Lycoming runs it in a test cell for an hour. Attached is a copy of the test report for my engine. That run takes a lot of the concern out of the first run after installation. I never noticed any big changes in temps or performance during my break in flights. All were done at about 75% power ROP using 25"/2500 at 2500' MSL. I never had high CHTs and I never saw them decrease. It burned about 7 hours/qt of oil for the first 30 hours and is now burning about 8 hrs/qt. Talking to other owners and Lycoming the oil consumption is a bit of a crap shoot. Some burn more some less - no one seems able to predict or explain the variation. I changed the oil at 10 hours (some Lycoming docs say ten, some say five). I figured ten was reasonable since the oil had been removed and replaced with preservative, and a new filter installed, after the test cell run. There was very little metal in the filter at ten hours. I changed the oil again after another 30 hours and switched from Aeroshell 100 to Aeroshell W100. The filter had only half a dozen small flecks of metal. I also did an oil analysis (Blackstone) at 30 hours and the metals were normal. Compressions at this time were 1-79/80, 2-79/80, 3-78/80, 4-79/80. My conclusion is that the most critical part of the break-in is done during the test cell run. After the first ten hours, I flew normal missions at 75% and just didn't do any stalls, slow flight, touch and goes, long low power descents and such. Skip Test Report.pdf
  5. You didn't say if the stains are on the top or bottom of the wing, but from your description it sounds like the bottom. In that case, it might be easiest to use some acetone to remove the sticky stuff and then polishing compound to remove the stained paint. If the paint ends up too thin or down to the primer, you can take the tail access panel to an auto paint shop and get a color match in a spray can and touch it up. It won't blend perfectly but underneath it won't be noticeable. Even if it's on the top of the wing, you will have to look really hard with the light just right to notice the repair if you use a little polishing compound to blend the edges of the paint. That's what I've been doing with some blemishes in my paint and no one but me notices them. Skip
  6. How do you apply it? Do you take the leaking screw out and coat the screw with it, or do you paint it on top of the screw? Does it work well in the wing walk (always problematic) area?
  7. Didn't @Cody Stallings mention some magic sealant he uses for fuel tank screws a while back? Skip
  8. Lycoming shipped my A3B6 with Slick mags: 4372 (impulse coupling) on the left and 4370 (no impulse coupling) on the right. That is the condition that SHOULD have the strap installed as the purpose of the strap is to ground out the right mag so it doesn't operate during starting. Since the right mag doesn't have the impulse coupling, the spark will not be retarded during start and it will fire the plugs too early at the low cranking rpm without the strap. You only remove the strap if you have two impulse mags installed or if you have the dual mag on the A3B6D. Check with your A&P. Skip
  9. Much better to have a backup AI than a turn coordinator especially for IFR training. The examiner cannot ask you to do anything that the airplane is not equipped to do. So... no pesky partial panel timed turns. BTW the early Cirrus SR22 had an Avidyne glass panel and a backup AI and an S-TEC autopilot with the turn coordinator required for the rate-based autopilot mounted behind the panel out of sight. Skip
  10. Good point, Ross. I was thinking of cruising around 5000 - 8000 ft. Skip
  11. Valves don't burn because of high EGT. They burn when there is a problem with dissipating heat through the seat. Seat eccentricity (Continental has had some problems with this), sticking (both Lycomings and Continentals but more common on Lycomings I believe). High CHTs will impede the heat transfer. For longevity, control the CHTs and don't worry about the EGT except as a leaning reference. Skip
  12. In my experience with Lycoming 320/360 series engines, leaning to roughness and the richening to smooth yields 25-40 deg LOP in fuel injected engines and near peak in carbureted engines (except for the PA28-161 which will run smoothly LOP). Skip
  13. If you don't tape the edges, the bare edges of the aluminum insulation material can scratch the plexiglass (happened to a friend). Cloth tape is probably better than aluminum tape to tape the edges with something that won't scratch.
  14. This is an interesting point. For an ideal Otto cycle engine, the ignition occurs at TDC and the mixture burns instantaneously at constant volume and then expands adiabatically (without loss or gain of heat) as the piston moves down on the power stroke transferring work to the crankshaft. In a real spark ignition (SI) engine, the mixture takes a finite time to burn and there is a rise in pressure to a peak and then a decline. The peak pressure position (PPP) measured in crankshaft angle (degrees after TDC) is determined by mixture strength, rpm and spark timing. There exists a PPP for each engine (based on engine geometry) that will produce the maximum brake torque (MBT). Operation at MBT produces the greatest efficiency. In automobiles, the spark timing is viable allowing PPP to achieve MBT over a range of operating conditions. Our engines have fixed timing, and the rpm is variable only over a limited range due to propeller efficiency. Thus, our primary control to affect PPP is mixture. LOP mixtures operate nearer the ideal PPP which is why LOP mixtures have the lowest brake-specific fuel consumption (BSFC). This all is just the physics behind why LOP is more efficient than ROP. For the pilot, it means that if you can get the same power (meaning true airspeed since that is what the power is converted to in cruise) running LOP as you can ROP, then LOP will be the more efficient choice. This is clearly apropos to turbocharged engines. For normally aspirated engines, if you can accept the airspeed generated by operating LOP at a particular altitude, then LOP is again your most efficient option. If you need to go faster and the throttle is already wide open, you will have to run ROP and accept the lower miles per gallon. BTW, the loss in efficiency from operating off MBT by 5 degrees or so is small, which is another way of saying the optimum operating point is broad. This is why Lycoming could change the timing from 25 deg BTDC to 20 deg BTDC without claiming a power loss -- the loss was absorbed in the tolerances permitted by certification. But the engine will produce slightly more power with the 25 deg timing. Chapter 2 of the attached document has some interesting description as well as measured engine data. Skip Maximum Brake Torque Timing.pdf