| Bob,
If it were me I would ask to talk to Monty Barrett. Besides knowing the engine he knows the IVP installation and all the cooling mods George Braly came up with.
2nd, better to get this resolved than cruise around at lower power settings, for engine breakin reasons. You want high pressure on the rings normally.
Stabs in the dark: - 1 degree per second is huge. it strikes me as more about the combustion event than the cooling. Have you ruled out: ignition system, ignition timing, spark plugs, helicoils (or other things that glow), local fuel flow. - did you do a GAMI lean test? If there is a local fuel flow problem it would show up as no peak or peak at a very different flow relative to the other cylinders. - did you look at the egt/cht log relative to your power setting changes? - did you calibrate your mp transducer? - If you have thorough pics of the old installation I would go over them carefully and look for differences in the baffle fit and and airflow. - cyl #5 you need the little hole in the front baffle with the hat on it to line up with the flat spot on the cylinder so you get cool air around and under the cylinder. - all cylinders including 5,6 need little air guides underneath to force the air through the lower fins. If any of those didn't get put back where they came from, that would cause a problem. - I would be suspicious about what had to change in order to reroute the spark plug wires. Are they blocking air flow underneath the cylinders? Did they open a hole in the baffle? - speaking of: the front cylinders don't get any flow if there is a big leak at the back. - The total pressure above the engine could be compromised by leaks around the spinner, especially if the engine doesn't fit into the cowl the way it used to. - did you change anything that would affect the exit flow from the cowl? On Jun 20, 2012, at 7:15 PM, Bob Rickard wrote: IV-P non turbine Fellow Pilots:
I recently received a rebuilt TSIO-550 from Barrett Precision Aircraft in Tulsa. Was quoted 9 weeks to overhaul, took 5 1/2 months (but that is another story). The good news is that the motor is back in the airplane, and looks and runs fantastic. My problem is, its running hot inside my airplane. The bottom line is - I am looking for suggestions on how to solve the problem described below- I have about 600 hours in my airplane on the previous engine, have taken the GAMI course, and run LOP cross-country almost exclusively.
Motor installed and test run. Every effort to try and install exactly like it left - only exception is spark plug wires installed below the air tubes (they were on top before - I don't know why the mechanic put them underneath). No problems with Cowl off. First flight - one pattern only - Max MAP was set too low, low fuel flow - fixed. Next flight - 10 minutes - Cylinders 5 and 6 temps run away hot at 38.5 MAP and 45gph. Must retard throttle to less than 25gph (25ish MAP) to keep under control. Third flight - after checking baffling for hours and scratching head - same deal. Fly for 1 hour full rich at low power settings. Motor very smooth and happy at low settings, but as soon as throttle pushed in, cyl's 5 and 6 climb at about 1 degree per second - power always retarded not to exceed 390 and cool down in the 350-360 range before trying to push up power again. Fourth flight - today - a 2.3. Takeoff WOT and full rich. Can't get above 3000' agl before having to pull power for cal 5 and 6. Pull power to 25gph/25 MAP/Full rich and slowly climb to 10.5k MSL. Fly there for a while, cylinders all look great in the 340-350 range. After an hour, try full power climb, have to stop within 1500' of climb. So then I leveled out, and set my typical speed cruise LOP mode to try something different - 34MAP, 2500 RPM, 18-19 gph. Motor is very happy. All EGT's normal (actually less than previous engine by almost 100 deg), CHT's all between 340-365. I climb with this setting to 16.5 and cruise for another hour, no problem. Return to base, set full rich/2700 rpm, and land normally. At retarded power settings in the pattern, motor stays cool and happy.
So what to look at? New motor mounts make the engine sit noticeably lower in the cowl, and we are checking the rear baffling to make sure there is a good seal, but would that affect the front 2 cylinders (5 and 6)? Every other indication (including the other 4 cylinder temps) are totally normal. Any other suggestions out there to look for?
Appreciate your experience
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