High EGT on one cyl when leaning on ground. OK in the air. Any ideas?

[jdeas]

Some flow dividers have a V-notch that comes into play at low flow rates. A little bit of dirt will alter the flow quite a bit!

[chazking]

How would one test for a 'spec' in the flow divider 'V'?

Flow test (boost pump) with closed throttle?

My flow test with WOT showed consistent (same) level for all six injectors.

Cyl 2's EGT runs 100 - 150*F hotter than other cylinders in 900 to 1200 rpm on ground. Cyl goes very high when eng throttling back for landing.

Have cleaned injectors, new injectors, cleaned divider, installed new plugs, replaced gasket on #2 intake pipe. No chg; same issue.

Fresh ideas welcomed.

[zav6a]

Can't say I ever look at the numbers when on the ground. Just check to see that they all go up when you shut off a mag.

Presuming your ignition systems are operating properly, if you lean to roughness and that cyl does not misfire first, it is not an over-lean issue.

You have not mentioned roughness. At idle that is telling you something.

After you have satisfied yourself that it is not a lean cyl, i'd ignore it on the ground.

[zav6a]

And with only 8hrs, I woulds not idle a minute longer than needed.

[ao.frog]

Thanks for the inputs guys.

Here's a few answers to your comments:

The engine runs smooth on ground from about 900 RPM.
Below 900, and down to idle (750-800 RPM) it runs alittle rough, but no more than other engines at idle that I've heard, nor does it run more rough than my other -7.

All EGT's have not shown any erratic indications, just the normal up and down values together with throttle movements and/or mixture.

The engine has now 13 hrs on the tach and it has been running VERY nice from the very first start.
Very little vibrations, stable engine indications and it feels smooth and nice.

I'm still running it hard according to the Lyc breakin SB.
No sign of CHT drop yet, but the oil consumption is down to 0,1 litres/hr. During the first hour, it was 0,5 litres/hr so it looks to me that the engine is well on it's way to breakin.

I'm limiting two things to the absolutely minimum: ground time and idle in the air.
The only time I'm idling in the air is actually the flare... and even then I don't go all the way to idle, I'm carrying alittle power and goes to idle a few sesc after touchdown.

To avoid low powersettings in the air when slowing down for landing, I'm flying longer finals with full flap, thus the powersetting can be as high as possible.

Anyway: here's a pic taken on long final the other day, tach at 10:98, MAP at 19%. As you can see, there's no EGT spread here either.




So I guess the next step is to check the spider. Does anyone have a pic how it looks inside?