Hello again everyone, I am Mark Schwendeman owner of O-235 L2C powered Long Ez 83DF. As some of you will recall I had a problem with #4 cylinder running way hot at about 435 F. I’m happy to announce the problem is now cured. It was not an air leak in the intake system as many of you suggested, I took the entire intake system apart and had no change in temps when it was carefully reassembled, however I do appreciate all the letters, suggestions, and clarifications from those who responded to my e-mail inquires. I finally cut a 2 inch by 3 inch hole in the front of the top cowling and built some ducting from this hole to #4. This worked; I got the temps down to about 390 F and flew to Memphis for help from the gurus, Robert and Valerie Harris. Robert plugged both my intake hole and the ramp exit on the top cowl. He built new baffles on the bottom side of #2 and #4, and built new baffles on the front side of #4. Essentially #4 cylinder is now enclosed in baffling except for a couple inch intake area on the bottom side of the cylinder and a couple inch exhaust area on the top side of the cylinder. Here are the before and after temps:
8500 ft, OAT 50 F, 2800 RPM, 146 KIAS, oil 181 F / 69 PSI, throttle cracked to slight RPM loss.
......... Before....................... After
#4 435 F / 1400 F..... 376 F / 1400 F
#3 365 F / 1300 F..... 365 F / 1320 F
#2 370 F / 1360 F..... 336 F / 1343 F
#1 373 F / 1300 F..... 362 F / 1250 F
Some of you may notice the head temp on #2 is also down as it is benefiting from the new underside baffle between #2 and #4. The #4 temp goes up to about 400 F when leaned out at 12,500, but that’s way down from 460 F. Those of you wondering about my experience with the “Vortex Valve” intake mod, it is now removed but I will be sending it back to get a shorter one built. I hope this will get the 20 RPM static thrust loss back and better mixture distribution. I’ll let everyone know how it works when I get it installed. For those who don’t remember my first posting it’s back on 3 Jan 06 entitled “One Hot Cylinder”. Thanks everyone,
Mark Schwendeman
