Fouling plugs during break-in

[acam37]

I have a freshly overhauled 0320E2G with new slick mags, New Kelly Aerospace ignition harness and 8 brand new Tempest plugs. The issue I'm having is even after aggressive leaning while taxiing to the runway, the engine run-ups indicate the typical lower oil fouled plugs. The engine runs fine on both mags but cutting one mag it runs like (you know what). Post flight taxi back to the hangar and it runs rough again. This engine only has 4.5 hours total time and has channel chrome cylinders. We are breaking the engine in over the airport at 4000' and 75% power, staying as close to the break-in procedure as possible trying to avoid the dreaded glazed cylinders. My question is, does this sound typical or should I be concerned? The lower plugs are dark black (indicating rich condition) and usually full of oil after I pull them.

[bruceh]

I had fouled the lower plugs twice with my engine before the rings really seated. No issues after the first 10 hours of flying. Just keep running that engine hard!

[zilik]

Arlie,

I can't help you with your plug fouling problems but I do know where Nacogdoches is. My father lives over by Wells so my wife and I fly into KOCH when we visit. Seldom do I see any planes and never have I seen an RV wondering about. Maybe someday we'll cross paths.

Until then, happy flying.

[Raymo]

If by fouled you mean lead fouled, leaning the engine should help. If it is from oil, not much you can do but go to a hotter plug, which will hold more heat and hopefully help avoid the buildup.

Here is a document by Lycoming that is a good read as well.

http://www.lycoming.com/Portals/0/te...%20Fouling.pdf

[rightrudder]

The flight school I rent from swears by using fine-wire plugs for the bottom locations. They claim they're far more resistant to oil fouling.

[bruceh]

My fouling was oily and on auto spark plugs with dual P-mags. It will improve after the rings seat.

[Mike H]

I would install REM37BY plugs in the lower holes and continue to run it hard to try and wear in the rings and cylinder wall plating. The BY plug is specifically designed to be a foul resistant plug for this type of application. Some operators run BY plugs in all locations all the time.

[acam37]

The plane flew for 2 hours yesterday. Justin, my plane partner and break-in pilot said that about halfway through the flight the engine began running better than it ever has, like scary smooth. It now has 7 hrs SMOH, so maybe the rings are beginning to settle in. He did a run-up after the flight and said it was a little rough but nothing like it was previously.

[Canadian_JOY]

The E2G is one of the better variants of the O-320, or so I've been told by every overhaul shop I contacted when I was looking to get one overhauled. They are the standard engine in the Grumman AA5 Traveler and AA5A Cheetah airplanes. In the Grumman world, the "fix" for fouling is going to 37BY plugs on the bottom, and if that doesn't work, open your wallet and dole out the cash for fine-wire plugs.

[redbaron]

Check to make sure that the engine RPM is correct. I had a Cessna 210 that had the same problem and found out the Tach Ind. was reading 200 RPM off. and the rings would not seat and had to deglass the cylinders.