Odd Temperatures after overhaul

[Jay]

Ok folks, here is one I'd appreciate some feedback on. The IO-320C1A engines on my Twinkie were just overhauled to new tolerances with ECI Titan cylinders. We did the first test flight in accordance with Western Skyways recommendation, basically stayed low and kept the power up for an hour. No problems. The second flight I went higher and brought in the turbos, and observed odd temps on the left engine. After a couple of more low level flights, I had the airplane up yesterday at several different altitudes.

Both engines are running smooth, and each burned 1 quart of oil in the first 5 hours. The temps on the right engine (recorded with a JPI 760) are very tight. The left engine, not so much. Basically the left engine starts out with the temps pretty close, but as I climb and bring in the turbos, they develop a spread between the 1 and 3 cylinders (running cooler) and the 2 and four cylinders (running hotter). Here are temps at a couple of altitudes for example:

In cruise @ 7,000, 75%,WITHOUT turbos, leaned to 10.5 GPH (over 150 degrees rich of peak) on both. Cowl flaps open, OAT 10 degrees C.

Left engine
1 EGT 1220 CHT 346
2 EGT 1200 CHT 374
3 EGT 1110 CHT 381
4 EGT 1270 CHT 391

Right engine
1 EGT 1260 CHT 337
2 EGT 1240 CHT 348
3 EGT 1260 CHT 338
4 EGT 1310 CHT 355

In cruise @ 9,000, 75%,WITH turbos leaned to 12.4 GPH (over 150 degrees rich of peak) on both. Cowl flaps open, OAT 4 degrees C.

Left engine
1 EGT 1210 CHT 366
2 EGT 1290 CHT 417
3 EGT 1100 CHT 379
4 EGT 1320 CHT 430

Right engine
1 EGT 1260 CHT 359
2 EGT 1250 CHT 360
3 EGT 1270 CHT 355
4 EGT 1310 CHT 367

After I took those readings I riched the left engine up to 13GPH to bring the temps down to less than 400 on 2 and 4.

You can see that the disparity on the left engine at 7,000 feet, but it isn't by much. As I go higher, it gets more and more extreme. I should note that the number 3 EGT has always been lower on the left engine, I think that is possibly probe placement.

The baffles were worked over extensively on both sides and are pretty darn tight. I'm thinking injectors on the left engine. They were all "overhauled", but I expect that means just cleaned. I'm considering trying GAMI's, but thought I'd get the thoughts of the group first.

Thanks in advance,

Jay

[charles Melot]

The only factors common to those two cylinders are cooling air flow and the upper deck pressure line. You could eliminate nozzles by swapping. I do recommend GAMI's. Charlie Melot Zephyr Aircraft Engines

[Jay]

Thanks Charlie. We are going to swap nozzles and check for leaks or blockages in the upper deck line. GAMIs may be in my future too.

Thanks again,

Jay

[Bill Creech]

[Jay]

I've continued to have some goofy EGT/CHT issues on the number 2 and 4 cylinders on my left engine. I've also had the number 4 injector plug once.

The fuel system has been thoroughly flushed on that side, and we found and fixed a leak (loose fitting) on the upper deck reference line, which improved things somewhat. We are now installing GAMI injectors. I'll report back on results.

Jay

[Jay]

[N3322G]

[Jay]