E.G.T help/question

[evil_hitman]

short answer is yes.
most probes are 1/8" NPT, there is the occasional 1/4"
Technically these also require a tapered drill bit to suit.
being that the manifold is relatively thin you may be able to get away without using the tapered drill bit. just make sure you drill for the smaller end of the taper. Watching this with interest as i'm about to build a pyro guage (didn't like the look of the commercially available units) and am going to tie it in to a turbo timer so motor keeps running until EGT is below a certain level.

Also be aware that the 1/8" is not the diameter across the threaded area. May be obvious to some but i almost got caught out on this myself.

[Guy]

short answer is yes.
most probes are 1/8" NPT, there is the occasional 1/4"
Technically these also require a tapered drill bit to suit.
being that the manifold is relatively thin you may be able to get away without using the tapered drill bit. just make sure you drill for the smaller end of the taper. Watching this with interest as i'm about to build a pyro guage (didn't like the look of the commercially available units) and am going to tie it in to a turbo timer so motor keeps running until EGT is below a certain level.

Also be aware that the 1/8" is not the diameter across the threaded area. May be obvious to some but i almost got caught out on this myself.

I am going to be putting it into the cast section of the manifold (pre turbo) does that make any difference ?

[evil_hitman]

being less than 10mm i'd say it should be ok. I'm no expert by any means, just passing on the things i was told by a friend of mine who works in the tool making game. The tapers aren't that big so for that depth of cut it should be ok.
I'm putting mine in the same place on my vehicle (GU 4.2 factory turbo) and this is what i was told. mind you he has tapered drills and with a new job i start on monday the vehicle will no longer be a daily driver so i'm just going to give him the manifold and pick it up a few days later.

[KiwiBacon]

Ok so the next question is what is the best way to attatch the probe to the mainifold.
I want to drill and tap the manifold to allow the threaded brass "bung" that came with it. The bung appears to be an NPT thread ( I think thats the term as the bung is tapered getting wider as you go up)

Can you get a tap to make that kind of thread ?

Brass is no good, it softens and loosens at the temps your exhaust manifold will reach.
Steel is good, stainless will look better for longer. In this part of the world BSP (british standard pipe) threads are easier to find than NPT.

The fittings I have take a 6mm probe and have a 1/4" BSPT (T= tapered) thread on the other end. I use a BSPF (F= parrallel, used to be BSPP, don't ask me why) tap with an 11mm drill.
The cast steel/iron materials that manifolds are made from drills and taps very nicely.

[Guy]

Thanks for another very informative post..
I will pop down to the local bolt place to go see what I get get to do the job.