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nbachert

Well Known Member
Patron
My question is how to measure for the hole location. I understand that I want them all the same distance down the pipe. I'm using a 4 inch piece of string because dynon suggests 2-8 inches and my #4 cylinder doesn't have straight pipe until that distance. I'm measuring the side of the pipe, almost as if I was measuring down the center of the pipe if that makes sense. You can't measure the outside or inside of the bends because that will give different placements. Is this the way to measure these holes? Also, in all the other posts it mentions to leave the sparkplugs open and general maintenance. Well what are general maintenance things and any other thing to check before I drill these holes. Thanks for the advice,

Nick
 
the probes burn out. I've replaced 2 already; 1 at 290 hours and one at 432hours. I can replace them without removing the bottom cowl and I lock wire the clamp screw so it cannot back out.
So thats the only kind of egt probe "maintenance" that I can think of.


nbachert said:
My question is how to measure for the hole location. I understand that I want them all the same distance down the pipe. I'm using a 4 inch piece of string because dynon suggests 2-8 inches and my #4 cylinder doesn't have straight pipe until that distance. I'm measuring the side of the pipe, almost as if I was measuring down the center of the pipe if that makes sense. You can't measure the outside or inside of the bends because that will give different placements. Is this the way to measure these holes? Also, in all the other posts it mentions to leave the sparkplugs open and general maintenance. Well what are general maintenance things and any other thing to check before I drill these holes. Thanks for the advice,

Nick
Click to expand...
 
Mount them around 2-4 inches from the head, plus or minus a 1/16th is not going to matter.

You do want them all about the same distance, so if there is a difficult tube that means 2.75" is the only spot for that cylinder, make them all 2.75"

The absolute values will vary on distance. Absolute values are of little importance for diagnostic purposes.

As for life, we flew 750+ hours before one probe failed. I replaced the lot, but 5 out of 6 looked in reasonable shape still. This varies a lot.

This is not like lining up holes on a skin to rivet. :D
 
Sounds simple, but make sure that the probe end sticking out clears the cowl, won't interfere with plug removal, etc.
 
Here are a couple

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IMG_2550.jpg
 
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