philiplane
A&P, IA, CFI, CFII, MEI,
11719.1
I had been chasing oil fouling problems in my left engine for a couple of years. Had all four cylinders off, more than once. Installed new rings, re-did mags twice, installed a new harness, you name it. Engine ran OK at altitude, but oil fouled during taxi often. Could never lean it very well either, because it would run rough. I recently found some service literature about checking the center electrode resistance, and the problem was solved. It should have hit me sooner because I already had Tempest massive electrode plugs in the right engine and it ran great. But that engine had nitrided cylinders, and the afflicted engine had chrome. So I was blaming the chrome cylinders the whole time, along with the rest of the ignition system. All because the Champion spark plugs weren't very old, and always tested good on the bench.
It turned out the problem was the flipping Champion spark plugs all along!
Guys, check your plugs asap. You will be rewarded with a really smooth running engine. I put Tempest fine wire plugs in both engines and I cut my oil consumption, plus I can lean it properly without running rough. I gave my two-year old, 200 hour Tempest massives from the right engine to a friend. (They looked and tested like brand-new).
He used them to fix his fouling problem in a Cessna 140. We checked his Champion plugs and 6 of 8 had over 200,000 ohms of resistance. And one had 950,000 ohms resistance. Now the engine runs perfectly. Who would have thought? Before this, no one told us to check the plug's resistance.
Also turns out that the high resistance spark plugs can damage the magneto. It causes arcing inside the distributor block. In severe cases it can melt the terminal and the mag fails completely. I have seen one of those myself on a friends plane, which has Slick mags.
Here's a link to a blog series on spark plugs:
http://www.flyplatinum.com/blog/?p=768
I had been chasing oil fouling problems in my left engine for a couple of years. Had all four cylinders off, more than once. Installed new rings, re-did mags twice, installed a new harness, you name it. Engine ran OK at altitude, but oil fouled during taxi often. Could never lean it very well either, because it would run rough. I recently found some service literature about checking the center electrode resistance, and the problem was solved. It should have hit me sooner because I already had Tempest massive electrode plugs in the right engine and it ran great. But that engine had nitrided cylinders, and the afflicted engine had chrome. So I was blaming the chrome cylinders the whole time, along with the rest of the ignition system. All because the Champion spark plugs weren't very old, and always tested good on the bench.
It turned out the problem was the flipping Champion spark plugs all along!
Guys, check your plugs asap. You will be rewarded with a really smooth running engine. I put Tempest fine wire plugs in both engines and I cut my oil consumption, plus I can lean it properly without running rough. I gave my two-year old, 200 hour Tempest massives from the right engine to a friend. (They looked and tested like brand-new).
He used them to fix his fouling problem in a Cessna 140. We checked his Champion plugs and 6 of 8 had over 200,000 ohms of resistance. And one had 950,000 ohms resistance. Now the engine runs perfectly. Who would have thought? Before this, no one told us to check the plug's resistance.
Also turns out that the high resistance spark plugs can damage the magneto. It causes arcing inside the distributor block. In severe cases it can melt the terminal and the mag fails completely. I have seen one of those myself on a friends plane, which has Slick mags.
Here's a link to a blog series on spark plugs:
http://www.flyplatinum.com/blog/?p=768
