EGT Probe 540 Lycoming.

[Macthediver]

First off HI everyone I'am new here.
Been a lurker for a while but now I have a question I'm hoping some one can help with. So I've registered and logged in.
I'm in the process of mounting an EGT gauge and installing the temp probes. My problem is there are no instructions with the probes. I've been told my best choice would be to put them on the center cylinders of my 540's exhaust tube. That said I have no idea where the sweet spot is for distance from the head?
What say the masses on distance from the head for the best temp reading? Someone has told me no more than 8 inches away but not what is to close?

Thanks in advance.

Mac

[GMAC 76]

my buddy runs egt on both sides and his probes are in the header collector just above the flex pipe clamp....io-540

[mwood7800]

My gauge lasted almost a season before moisture damage. I think the second gauge made it 6 months

[John Fenner]

We ran the Pyro meters about 2" below the flange. However we were using 2 digital temperature monitoring boxes that check temps at each cylinder (4) as we were running nitro/ methanol. For your application might be best at header collector.

[Planeguy]

Just 2 probes? I don't think I would mess with it at all. If you have a problem with a cylinder, 2 probes only give you about a 33% chance (less than 17% if only one probe) of being on the problem cylinder. The only reason I can think of for having them on airplanes is to lean the mixture for peak performance and it seems most airboats have the mixture lever tied to full rich. Many aircraft don't even have an EGT system. There are 5 piston engine (4 are IO-520's) airplanes without and one with where I work.

[gator7272]

I'm more a fan of the CHT's, Get a dual gauge and read off of your two center cylinders (as they are the hottest). I'm a fan of these because I believe it is the most accurate ( I may be wrong) method of preserving your cylinders/valve seats.

[rbjscott]

The probes should be 1-1/2 to 2 inches from exhaust flange. I have run exhaust temp on both aircraft and automotive engines. One each side is not ideal but still worth it.