pyrometer probe tap

[mfurrh55]

Does anyone know what size tap i would need to install a pyrometer probe?,I need to drill the hole in the manifold and tap it for the probe, Need to know what size it is, Thanks in advance, Monte

 

[JR]

It depends on the manufacture, I have seen a few different sizes. Have you bought a set already? Usually the instructions will tell you the size bit and tap you will need. If you know what size the threads are, I have a conversion chart I can tell you what it is.

 

[RustyJC]

All the thermocouples I've installed have taken either a 1/8" NPT or 1/4" NPT pipe tap for the adaptor that screws into the manifold.



Rusty

 

[mfurrh55]

It looks like a 1/4 " pipe thread on the install nipple, just wanting to make sure before i drill it out, i am using my old thermocouple i had in the downpipe elbow before i added the jakebrake, couldn't find my tap i used originally to drill and tap with, this time ii was going to drill the manifold and put the probe in a better spot for truer reading, thanks for the replies, Monte

 

[JR]

1/4 npt requires a 7/16 drill bit. If your not positive of the size you can double check the probe fitting by screwing your probe into a standard 1/4 pipe fitting.

 

[mfurrh55]

1/4 npt requires a 7/16 drill bit. If your not positive of the size you can double check the probe fitting by screwing your probe into a standard 1/4 pipe fitting.

Ok, i'll give that a try, Thanks, monte

 

[mfurrh55]

1/4 npt requires a 7/16 drill bit. If your not positive of the size you can double check the probe fitting by screwing your probe into a standard 1/4 pipe fitting.

Found a 1/4 tap and is bigger than the probe nipple, so now i am guessing it is the 1/8", what size of drill bit will i need for the 1/8 tap?, 5/16 ?, Thanks for your help, Monte

 

[Joseph Donnelly]

Use an 11/32 drill to tap 1/8 NPT. Grease and remove the chips just before you brak through. then use a pencil magnet to clean out the passage. I like to drill downwards in a horizontal run of the manifold, not over the downward passage to the turbo. Usually you can put the hole just behind #3 port in the lengthwise runner.

 

[mfurrh55]

Thanks i'll do that,monte

 

[mfurrh55]

I bought a 1/8 " NPT tap and the package said to use a 21/64 drill bit, I figured i'd try it first before stepping up to a 11/32, and i think after using the 21/64, an 11/32 would have been too big and wouldn't have had enough thread left for the probe nipple, anyway thanks for the responses and all the help, I really appreciate you guys, Monte