Thermocouple location and getting through firewall

[lotzagoodstuff]

I'm getting ready to install my pyrometer and I gave it a quick look today and I think I want to put the thermocouple itself in a boss located in the rear most cylinder on the passenger side as I think it makes the most sense, however, I am guessing that since most folks like the pyrometer mounted in the driver's pillar they are probably going through someplace near the wiring harness/fuse box area. I would like to run the wire through the firewall using an existing hole and/or without having to cut a hole or make too much mess out of the firewall. It is a digital readout and I am going to put it down low on the bottom of the dash with a nice mount but I am willing to relocate it in order to make for a cleaner feed through the firewall.

Anybody have any good experience with installing a thermocouple and/or pyrometer?

 

[FordGuy100]

We put my thermocoupler in between the 2nd and 3rd cylinder back on the drivers side manifold, cause it was the easiest place to use a drill to drill out the holes.

My firewall had a rubber grommit for something to go through right behind what seemed like the drivers side valve cover, I pulled all my wires through there.

 

[suv7734]

Where you mount the pyrometer, thermocouple and how you route the thermocouple extension wiring is entirely up to you.
The closer you can mount the thermocouple to the cylinder the better.
Mount the gauge where it's easy to see.
The routing of the thermocouple extension wire won't matter unless you get into a run of 100's of feet. If the extension wire that came with your kit is too short you can get one that is longer and use it. Try to avoid areas where there is a lot of 'electrical interference' such as running it parallel to an alternator output lead.
Most of the thermocouples that are used for this type of application are type 'K' which means that one lead has yellow insulation and the other has red. Generally the casing for the leads/extension wire is yellow as well.
Never use solder to make any connections anywhere in your system. All of the connections must be mechanical (crimps or 'screws') so they do not introduce different metals into the 'system' which can/will cause incorrect readings.
It's funny this came up today since I just spent all day installing and routing 37 different type 'J' thermocouple extension wires (3,500+ feet) for a monitoring system in an aerospace heat treating facility. They deal with anything the flies from Boeing, Airbus, helicopters, space shuttles etc. Neat stuff.