So last week I took my daughter up flying and noticed my #1 CHT was running around 100 degrees cooler than the other 3. This is an IO-320 with 1 mag and 1 lightspeed ignition. I could also sense the power seemed off a bit. We landed, and doing a mag check I could tell the engine was dropping rpms. Thinking I might have a fouled plug I ran the engine up and leaned it out, but the #1 cylinder stayed cold. Like 160 degrees.
I pulled the plugs - they looked ok but I replaced them anyway. They had around 400 hours on them as I could find no mention of plugs being replaced in the logbooks. Plane is new to me as of May and has a total of 396 hours on it since engine was new. Anyway replaced the plugs, cleaned the injectors, and ran the engine up again. No change, #1 still cold. I checked the sensors by putting each in a cup of boiling water, and all measured appropriately. Compression check showed 4 consistent cylinder pressures. Finally checked the intake bolts and sure enough the #1 intake bolts were loose! Snugged them up (on all 4 cylinders), and ran engine up again. Voila’ - problem fixed. CHT and EGTs back to fairly consistent.
I like simple solutions. Thanks to VAF for guidance found here.
Ed
I pulled the plugs - they looked ok but I replaced them anyway. They had around 400 hours on them as I could find no mention of plugs being replaced in the logbooks. Plane is new to me as of May and has a total of 396 hours on it since engine was new. Anyway replaced the plugs, cleaned the injectors, and ran the engine up again. No change, #1 still cold. I checked the sensors by putting each in a cup of boiling water, and all measured appropriately. Compression check showed 4 consistent cylinder pressures. Finally checked the intake bolts and sure enough the #1 intake bolts were loose! Snugged them up (on all 4 cylinders), and ran engine up again. Voila’ - problem fixed. CHT and EGTs back to fairly consistent.
I like simple solutions. Thanks to VAF for guidance found here.
Ed