After about 600 hrs of run time on our O-320-E2D, fixed pitch prop, I've developed a rise in EGT on just the #3 cylinder and I just can't seem to figure out the cause. This happened rather abruptly, it's not been creeping up over time.
Here's the basic scenario. At cruise power settings of 2400-2500 rpm, full rich and 1000-3000 density altitude. I'm seeing 1450-1470 F on just cylinder #3, the others are 1290 to 1320. All four CHT's are between 320-340 F.
For the past 10 years these settings would lead to about 1370 on cylinder #3, so I've basically seen a 100 F rise over normal.
This high reading seems very steady, it does not oscillate. (as might be expected with a bad exhaust valve seat).
Here's what I've checked with no improvement:
1) installed brand new spark plugs in cylinder #3
2) did a hot compression check, (all cylinders 72/80 or better)
3) swapped egt probes, high temp stays with cylinder
4) changed the intake tube seal and checked for cracks on intake pipe.
5) checked and tightened hose clamps on rubber hose that connects intake tube to sump.
6) used a shop vac in blower mode to force air into the carb intake and used foaming bubble juice to look for intake leaks on every connection going to cylinder #3.
7) confirmed that the primer system is not connected to cyl #3
So there you have it. IDEAS would be greatly appreciated!!
Thanks,
Bob Newman
40176 finish kit
Glastar N99RN flying
Here's the basic scenario. At cruise power settings of 2400-2500 rpm, full rich and 1000-3000 density altitude. I'm seeing 1450-1470 F on just cylinder #3, the others are 1290 to 1320. All four CHT's are between 320-340 F.
For the past 10 years these settings would lead to about 1370 on cylinder #3, so I've basically seen a 100 F rise over normal.
This high reading seems very steady, it does not oscillate. (as might be expected with a bad exhaust valve seat).
Here's what I've checked with no improvement:
1) installed brand new spark plugs in cylinder #3
2) did a hot compression check, (all cylinders 72/80 or better)
3) swapped egt probes, high temp stays with cylinder
4) changed the intake tube seal and checked for cracks on intake pipe.
5) checked and tightened hose clamps on rubber hose that connects intake tube to sump.
6) used a shop vac in blower mode to force air into the carb intake and used foaming bubble juice to look for intake leaks on every connection going to cylinder #3.
7) confirmed that the primer system is not connected to cyl #3
So there you have it. IDEAS would be greatly appreciated!!
Thanks,
Bob Newman
40176 finish kit
Glastar N99RN flying