John,
1. I would set the EGT warning at 1650 degF. On a turbocharged engine, the only exhaust gas temp to be concerned with is TIT however I have found by setting my EGT to 1650 degF, I get an early warning of rising CHT’s if my EGT’s are slightly high. I run LOP and it is an early reminder to lean a little. I find this most relevant when flying at FL 220 and up. At full rich you should be in the EGT 1200’s range.
2. When doing a Mag check, make sure all EGT’s rise when switching to one mag and all EGT’s drop when switching back to both mags. Don’t worry about the drop. If you want to do a robust mag check, do this while at cruise power. Caution…tell your wife what is about to happen before doing this.
3. The Lightspeed must be advancing the ignition timing at 1700 RPM otherwise I would expect an EGT rise when selecting that source only. ??
Craig Berland
N7VG
Hello all,
Hope you don’t mind I may be a pain in the butt for a while. I’m breaking in this new Barrett Precision Engines TSIO 550 and hope some of you won’t mind answering niggling questions that will come up as I go through the process. I have about 6.5 hours on it now and the CHT’s are coming down nicely. Still running full rich and cycling the power in cruise from about 33 inches MAP down to 25” in gradual increments. Today I got to 12,500 and stayed there about an hour with CHT’s never going to 400 and after the initial climb and level off, they stayed below 380. Previous flights, I could not seem to keep #3 below 400 above about 10,000 ft, even when powering back. So it looks like the rings are seating well and break in is on track.
I did notice one thing that I don’t recall seeing before during engine run up before takeoff. The EGT’s all went to caution temps when I switched to the MAG at 1700 RPM. The drop on the MAG has been a bit high – usually over 100 RPM and inconsistent. Sometimes it could be 95 RPM and it has been as high as 145 RPM. Today I think it was close to the higher number. I have the EGT caution warning go off at 1475. I know that’s not particularly high but it’s the first time bitching Betty has gone ballistic six times in a row in short order like that. As expected there is no drop on the Lightspeed ignition and the EGT’s don’t seem to change much when selecting only that ignition source.
Any thoughts on that?
Regards,
John Barrett, CEO