For those of you who are running 0-360 conversions in your 170's, can you tell me what your exhaust gas temps are reading at 65% cruise? What temp is too hot?

Dont have a 170, but my 0-360 in the Scout will run about 1300egt at 65% if I remember right. I have had good luck keeping egt below 1400, and the cht never go more than 325 or so. Im sure every configuration will be different. Makes a big difference if you run low rpms and higher manifold in the Scout. I will burn 7.5 gph, egt 1350, cht 300 at 2000rpm, 22" mp and turn about 100 mph with bushwheels. Thats probably less than 65%, and leaned at altitude
JIm

EGT readings do not matter unless extremely high and there is a major difference between cyl. EGT readings are used for establishing peak egt when leaning. They are monitored for difference between cylinders which can be an indication of problems. Balance between cylinders is not easy to achieve in a carb engine because of intake leaks. There is a lot of information out there, so google Mike Busch of Savvy Aviation.

My information comes from over 5000 hours behind Avcom conversions in a 170B and two 175 tail wheel conversions and I never cared what the egt gauge said, only the changes it made based on what I was doing with the mixture.

Here is the link to Mike Busch story on egt in the October 2010 EAA Sport Aviation.

http://www.alcorinc.com/pdf/EGT_Myths_D ... t_2010.pdf

feedpro wrote:EGT readings do not matter unless extremely high and there is a major difference between cyl. EGT readings are used for establishing peak egt when leaning. They are monitored for difference between cylinders which can be an indication of problems. Balance between cylinders is not easy to achieve in a carb engine because of intake leaks. There is a lot of information out there, so google Mike Busch of Savvy Aviation.

My information comes from over 5000 hours behind Avcom conversions in a 170B and two 175 tail wheel conversions and I never cared what the egt gauge said, only the changes it made based on what I was doing with the mixture.

What Feedpro said. Also, EGT is a RELATIVE value, and will vary with installation, depending on precisely where the probes are placed in the exhaust stacks. Note that some EGT guages aren't even calibrated to temp....just tick marks for calibration. In other words, the actual number is irrelevant, it's the comparison of the different cylinders and/or the peak that matters when you lean.

On a carbureted four cylinder engine, Lycoming says pull the mixture till the engine power starts to stumble a bit, richen it up some, and life is good. I've done that for years with an O-360 in my 170, with a four probe EGT gauge, and it works as well as anything.

For reference my CHT's run around 320 on a hot day, with maybe 338 max in climb.

MTV

Thanks for the comments guys. Feedpro, I really like that article you linked. It certainly taught me a couple things.

I'm way hotter than both MTV and JrCubuilder. My CHT's are up around 400 on climb out during the summer, at Vx. At Vy I'm down around 360. Is it your opinions that I may be pushing it a little too much? Or do I chalk it up to probe location?

I typically see 320 when I'm in 65% cruise.

Thoughts?

Climb at Vx for training EXCEPT, use it on takeoff when the trees are viewable in the TOP of your windshield.

Vy works perfectly well for everything else.

MTV

Those CHT numbers sound right in the ballpark to me.