My partner posted about a EGT issue we were having where the number 3 EGT jumped up substantially over the other cylinders. Everyone seemed to think it was a clogged injector. We have been looking at the problem and need a bit more advice. It now appears sadly the issue may be a cracked cylinder or cylinders.
To fill in a little more history on the aircraft the very first indication that there might be a issue was slightly elevated EGTs on 2 and 3 at takeoff power. I first noticed this on takeoffs after the engine was heat soaked from a prior flight. First flight of the day it did not occur. The strange thing was that at the first leaning after takeoff the numbers would drop and match 1 and 4 and the rest of the flight would be normal. Some days it would be 2 only, another day 3 and some days both. Shortly after seeing this trend we had number 3 stay high throughout a flight. This caused us to ground the aircraft to investigate. Initial thoughts from both the forum and everyone we talked with were a clogged injector.
We took a good look at the engine and there are signs of exhaust residue on number 3. Local A&P felt we had a cracked cylinder on 3 and perhaps on 2. This matched what I was seeing on the takeoffs so I assumed that was the issue.
The cylinders on the aircraft are ECI group A (AD for possible cracking) made in 2003. They had a compression check just a 15 hours prior and were perfect. We are also running 10 to 1 pistons and for the last 200 hours have run the engine LOP. Total time is 780 hours. With further investigation the compression still checks perfect. The A&P questioned his initial cracked cylinder thoughts and thinks we might be seeing casting marks. Looking harder at 3 however it sure looks cracked but not near the barrel interface with the head which is what the AD was about. I am going to post some pics and see what the experts here might think. Engine has always been well cooled and never exceeds 380 degrees in climb and cruise is 350 or less ROP and low 300's LOP. Oil is 180 to 190 at cruise and 205 max on a hot day full power climb.
ECI has provided excellent support. In view of the AD we ordered 4 new cylinders from ECI and they helped by reducing the price. Now we are questioning what exactly might be going on. The area that appears to be cracked is above the spark plugs. Given the symptoms and pictures what does the forum think? We are leaning to changing all 4 cylinders and dropping compression to 9 to 1 however we loved the performance of the aircraft and engine with the 10 to 1's. Would like to keep them if they are not part of the problem. Open to any and all thoughts. Pictures to be attached shortly.
George
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Note that the location of the two possible cracks is below the top of the sparkplugs. The lines running to the spark plugs are casing marks.
To fill in a little more history on the aircraft the very first indication that there might be a issue was slightly elevated EGTs on 2 and 3 at takeoff power. I first noticed this on takeoffs after the engine was heat soaked from a prior flight. First flight of the day it did not occur. The strange thing was that at the first leaning after takeoff the numbers would drop and match 1 and 4 and the rest of the flight would be normal. Some days it would be 2 only, another day 3 and some days both. Shortly after seeing this trend we had number 3 stay high throughout a flight. This caused us to ground the aircraft to investigate. Initial thoughts from both the forum and everyone we talked with were a clogged injector.
We took a good look at the engine and there are signs of exhaust residue on number 3. Local A&P felt we had a cracked cylinder on 3 and perhaps on 2. This matched what I was seeing on the takeoffs so I assumed that was the issue.
The cylinders on the aircraft are ECI group A (AD for possible cracking) made in 2003. They had a compression check just a 15 hours prior and were perfect. We are also running 10 to 1 pistons and for the last 200 hours have run the engine LOP. Total time is 780 hours. With further investigation the compression still checks perfect. The A&P questioned his initial cracked cylinder thoughts and thinks we might be seeing casting marks. Looking harder at 3 however it sure looks cracked but not near the barrel interface with the head which is what the AD was about. I am going to post some pics and see what the experts here might think. Engine has always been well cooled and never exceeds 380 degrees in climb and cruise is 350 or less ROP and low 300's LOP. Oil is 180 to 190 at cruise and 205 max on a hot day full power climb.
ECI has provided excellent support. In view of the AD we ordered 4 new cylinders from ECI and they helped by reducing the price. Now we are questioning what exactly might be going on. The area that appears to be cracked is above the spark plugs. Given the symptoms and pictures what does the forum think? We are leaning to changing all 4 cylinders and dropping compression to 9 to 1 however we loved the performance of the aircraft and engine with the 10 to 1's. Would like to keep them if they are not part of the problem. Open to any and all thoughts. Pictures to be attached shortly.
George
Note that the location of the two possible cracks is below the top of the sparkplugs. The lines running to the spark plugs are casing marks.
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