New engine - ? GAMI check.
Thanks everybody for your responses to my (misplaced) post about when to do the GAMI spread test. All are appreciated and will be considered carefully.
Dan I apologize for taking so long to respond ? because the hoped for end of phase one got complicated. Take off and climb went well starting at Hobbs 36.25 hours. Temps, never a problem so far were fine; max cht 356 in climb, EGT?s 1100-1200, oil temp max 180. All with OAT 80 F on the ground, IAS 80 mph initial, increasing above 1000? to 120 mph. Had been worried about detonation or pre-ignition with my IO-360 M1B?s 10:1 pistons, so was running rich. Returning from a 130 mile x-c leg I got brave and leaned to peak EGT on 1 and 4, the two leanest cylinders. Everything looked good but I was still leery of LOP so stopped there. Downloads from the AFS 3400 gave peaks of 1421, 1376, 1340 and 1432. One and four peaked at the same fuel flow of 8.2 gph (MP 23.1, RPM 2360, alt 4500). Pulled RPM back to 2200 (MP at 22) to try low cruise (avoid continuous ops 2200-2350 for my engine-prop combo). Engine had always been very smooth but felt rough just as rpm reached 2200, suddenly. Stayed that way despite varying MP, RPM and mixture. On landing roll-out the engine quit . Never happened before. Rolled off and tried to restart, failed x2 and pushed plane to the hanger. Cowl off, everything looks good. Next day got engine started, ran OK on both and Rt (LSE III) positions and stopped firing on Lt (mag). Repeating the check improved the Lt mag firing but it was still spotty. Took out lower plugs (fired by Lt mag) which looked wet and dirty. Cleaned. Run up now good at 1800 rpm, so went flying. At 4500 ft, 22 square tried Lt mag again and engine quit firing. Back to take cowl off again (engine did not quit on rollout). Decided to pull mag, which failed resistence test on primary coil. New coil installed, lower plugs cleaned and regapped, mag installed and timed to 20 BTDC. We chose 20 BTDC based on threads here and the LSE manual. The engine data plate from Lycon says it?s an IO-360 (no mention of the M1-B in the logbook data) and specifies timing as 25 BTDC. We called Lycon and spoke to Lauren who initially said 25 BTDC was correct even with the 10:1 compression. But when he asked about electronic ignition and I told him the Lightspeed III was on the right, he said whatever it was set to should determine the timing. The LSE seems to be set for 20 BTDC and that?s why we chose the 20 degrees. Did a run up at 1800 rpm and found slight roughness, 160 rpm drop, and 200 degree rise in EGT on the left mag. Our A&P suggested going to 25 BTDC and this was done. Weather et all stopped us there and no run has been done with the new timing. Oh ? when the engine quit on rollout, it had stopped by 38 mph IAS with FF @4 gph. I?ll try to post the data dumps from the AFS later ? they?ve been printed out but I can?t get them up to include here. We checked the mag/starter switch - OK. Wiring harness to lower plugs looks good. We?re now at Hobbs time of 37.88 on the overhauled engine from Lycon ? but it?s old, delivered to me just about 10 years ago. Wonder about replacing the harness to plugs because of age? To your earlier ?'s Dan; It says Bendix on the servo body. Fuel flows from the red cube are very stable, but lag behind movement of the mixture control.
I respect your opinions Dan and would like to hear your thoughts about all this, if you?re willing. Thanks in advance to you, and again to all other posters.