EGT probe hole size???

[JIG 4 2NA]

I am in the middle of changing my injection pump injectors new lins new ceramic coated manifols oil cooler and lines and new 4" exhaust.

I dont have a egt gauge yet but since everything is apart I just thought to drill a hole in the pass side manifold for a egt probe but want to find out what size to drill. I figure I would just drill the hole and tap it for the size of the probe then just put a pipe plug in until I get a gauge.

Are all the probes pretty much a standard size? If so what is it? I am most likely going to buy a auto meter ultra lite egt and boost gauge if that helps fro people that used auto meter guages.

 

[Twisted Steel Performance]

1/8 NPT threads....

 

[Burning oil]

Actualy 1/4" is all I have seen. Worst case you can bush down to 1/8" harder to go other way. Just make sure when you buy its got what you need.

 

[Husker6.5]

Hmmm, interesting Leroy, as 1/8" NPT is the most common size I've seen over several manufacturers with 1/4" NPT being the odd man out. Which brand of gauge do you have that uses 1/4" NPT for the thermocouple probe? Summit Racing says that Autometer uses 1/8" NPT for the probe on all lines of their gauges that offer exhaust temperature gauges, as I believe Stewart Warner does also. Glowshift also uses 1/8" NPT for their probe.

Perhaps Isspro uses 1/4"?

 

[Burning oil]

Its been about 4-5 years ago, cant remember brand. Back when I bought mine all I saw were 1/4" probes. So to the OP you'll need to find out what you'll need before drilling. If thats impossible drill 1/4" then bush down if needed.

 

[Burning oil]

Just remembered it was a Westach gauge. The previous EGT in my old 93 was also 1/4"

 

[Husker6.5]

I am in the middle of changing my injection pump injectors new lins new ceramic coated manifols oil cooler and lines and new 4" exhaust.

I dont have a egt gauge yet but since everything is apart I just thought to drill a hole in the pass side manifold for a egt probe but want to find out what size to drill. I figure I would just drill the hole and tap it for the size of the probe then just put a pipe plug in until I get a gauge.

Are all the probes pretty much a standard size? If so what is it? I am most likely going to buy a auto meter ultra lite egt and boost gauge if that helps fro people that used auto meter guages.

If you're going to use an Autometer pyrometer, they should be 1/8" NPT for the pyrometer thermocouple, but check with Summit to confirm. Three things to make life easy for when you do eventually install the probe. 1) Use that square shaped "pad" on the passenger manifold below the turbo mounting flange for the drilling site, it's like some GM engineer thought "Here's the perfect place to mount an EGT thermocouple, I'll design a casting boss there to drill and mount it" - till a bean counter said no factory EGT gauge, it'll cost us X dollars per unit additional cost. 2) Use a stainless steel pipe plug, for the buck extra it will eliminate many problems if it's a while before you install the probe. 3) Use a goodly amount of quality anti-seize on the threads and don't over-tighten if you want to get the plug back out easily.

 

[bigdaddyinacaddy]

I got my auto meter pyro and boost gauges from ssd, and I too had to bush from 1/4 to 1/8. The tapped hole in heaths crossover is definitely 1/8, for the record.