I did a search and didn't find this anywhere. I have the 1/8th" thermocouple and I am not sure which drill bit and which tap to use. Anyone remember?

 

Just bought my drill and tap yesterday. 1/8"x 27 npt tap and 11/32" drill called "R".

 

A 5/16 drill bit is the recommended size for the 1/8th tap. The 1/8 by 27 is the proper tap. Good luck with the install. Very easy to do.

 

Machinist manual calls for .....
1/8-27 NPT use "R" (.339) dia. drill

Don't use a 5/16" that's .3125 and makes it difficult to tap.

Check out my article I did for a Duramax. It has a lot of good tips for tapping.

 

Well, 3.5 hours and I'm all done. I even stopped for breakfast.

I used an 11/32" bit and of course a 1/8" npt tap. No problems at all. I did not pull the manifold or turbo off. It would have taken a lot longer. I just swept the inside over and over again with my telescoping magnet until there was nothing left on it. You just have to make sure you run the tap deep enough or it's really tight trying to put the fitting in. Put a little anti-seize on it and I was done. Only thing left is to wait till dark and see if I like the clear light or the green one better. Which ever one matches the factory guages better that is...

Next up, fuel guage with the cool fuel filter cap from Genos that has a hookup right on top for the guage. Then probably a Holley blue pump... Boy, that oughta make my wife really happy..

Have pics in my gallery as soon as they are approved.. DONE,,,,,,,and looks good! ,,,,, (Admin)

 

Curious. My chart shows a 5/16. I guess its wrong.

 

Well, there's not much difference in the 5/16" and 11/32" bits. The 11/32" makes it easier to tap but I'm sure that with the 5/16" the threads would have been deeper. Either way, mine worked great.

 

And that s the most important part. You have the identical setup to mine. I also have the SRT 10 pillar along with the EGT/Boost gauge. You might want to put a ty-wrap on the boost tubing both (in case you haven't already) at the engine and gauge to prevent the hose from blowing off with max boost. Mine did that more then once but the ty-wrap cured it.

 

"You might want to put a ty-wrap on the boost tubing both (in case you haven't already) at the engine and gauge to prevent the hose from blowing off with max boost. Mine did that more then once but the ty-wrap cured it."



If you check my gallery you will see that i did that at the engine side. The guage side seems really tight but I may do the guage side too while I'm putting the little green cover on the light bulb..