Just picked up a new exhaust manifold from cummins and I wanna drill and tap it for a future egt probe. I'm wondering if all egt guages use the same size hole and thread? I'm thinking I would drill and tap it and plug it with a bolt until I get around to getting guages. Good idea or do I need to get the guage now?

 

Welcome to DTR!

Now its time to learn how to use this magnificent resource to your advantage!

Do a search on the EGT probe and you will find hundreds of posts!!! If not thousands. You may even find which size tap to use for which particular probe that your mfg uses!!

In any case I'd personally not tap it until needed as you may change your mind after doing a search on which guages to buy!!!

You have much reading to do!!!

Have fun!! And, again, Welcome!!

Rick

 

I should look this one up but ( very sorry) don't want to go out to the truck. They do give you a measured spot to drill to put the pyro sender . You can drill it 1/4" and reduce it to 1/8" with a reducer if you want to go that way. The thread size that you are going to drill for, is pipe thread which is different then machine thread. Do use a tapping fluid when you do this process. When you drill it you will put in a plug of 1/4 or 1/8 " size. Which ever size you choose. Check the different types that are put in for pyro's and this will tell you what size to install. DO USE, a Copper Cote type product that doesn't change the torque spec like Never Seize does. I do find that Copper Cote lasts longer under under harsher conditions. The latter will change the amount of force that is exerted on the threads which may strip them. This is why tire shops have changed what they use on tires. ( transport trucks).

 

Mine used what I think is pretty common, it was 1/8" npt thread, it's pretty big diameter when you get the depth down to where you need it. (it's a tapered thread). Personally I would be hesitant to drill the 1/4" npt after seeing the size mine took.

BTW: my gauges are Isspro's...

NPT= pipe thread

 

I guess it'd be a good idea to wait until I get the guages to drill the thing. I'm just getting tired of the whistling from the huge crack in my exh. manifold. Oh well, I'm not really looking forward to the process of replacing it seeing as the truck has 186k on it, its probably welded on pretty good by now.

Thanks guys.

 

I'd just do the 1/8 NPT. At least then you have your hole already started for when you go at it again. Plus, if you drill w/ it on the truck, there will be less shavings.