Chevy and GMC Duramax Diesel Forum banner

1 - 18 of 18 Posts

·
Premium Member
Joined
·
2,144 Posts
Discussion Starter #1
I BOUGHT THE EVO RACE AND WANT TO TAP THE EGT PROB WHAT DO I USE AND WHERE TO TAP IT ALSO DO I DO IT WHILE TRUCK IS RUNNING?


Thanks
 

·
Registered
Joined
·
2,480 Posts
I would leave the truck off while taping but once tapped let the truck run for a few minutes to let the shavings get out
 

·
Premium Member
Joined
·
2,144 Posts
Discussion Starter #3
ok do i use a drill bit to do this ive never done it , i have not a clue
 

·
Registered
Joined
·
13,927 Posts
Size R drill bit, and 1/8"-27 NPT tap. We drill and tap them with the truck running. We also hold the shop vac near the hole to get as many shavings from the outside we can. Or you can pull the manifold, it takes about 15 minutes.
 

·
Needs more go fast
Joined
·
12,518 Posts
i tap mine without it running and just used a shop vac and sucked out all the little metal shavings that fell in
 

·
Registered
Joined
·
1,460 Posts
Okay I'm guessing you've never tapped anything before. So that being said listen up.

DO NOT USE A DRILL TO TAP. I think an 11/32 drill bit works fine, I used one because I couldn't find a R drill bit. Drill out the hole with what ever bit. tap it by hand, its hard to get started but just keep all the downward pressure on it as you can and go slowly, eventually it will grab and start to dig in. Go in about 1.5 turns then back it out, then go in about 2 turns from where you are now and back it. Just continue to tap and back it out, then tap, then back etc. This keeps the threads from bugering up, and also keeps the heat out of it.

You could rub vasoline on the tap, that will allow something for the metal shavings to stick too. I don't think you need any type of lubercant though on cast iron so its just for catching the shavings mainly.

Use one of those telescopic magnets when your done.
 

·
Registered
Joined
·
215 Posts
I did all mine while truck was off and sucked the shavings up with a shop vac.
Make sure you DONT use too big of a drill bit, or you'll have to plug it and start over
 

·
Premium Member
Joined
·
2,144 Posts
Discussion Starter #10
so you guys are saying do not use a drill do it by hand ?
 

·
Registered
Joined
·
144 Posts
I leave the truck off, use bearing grease on the drill bit and tap and then a telescoping magnet when im done...... just my .02
 

·
Premium Member
Joined
·
2,144 Posts
Discussion Starter #13
you have alot of vehicles
 

·
Registered
Joined
·
461 Posts
i have done mine always while running and put some grease on the tap, as stated drill it with a drill, but tap by hand with a t-handle, and make sure to wear safety goggles becuase with it running it deffinetly blows all the shavings right out.

also put toward the rear of the passenger side manifold, there is a semi-flat spot there that works well. just pull out the inner fender well, get your rollie seat and take your time so you don't break the bit or the tap off.
 

·
Registered
Joined
·
152 Posts
I leave the truck off, use bearing grease on the drill bit and tap and then a telescoping magnet when im done...... just my .02
x2, same way I did it.
 

·
Registered
Joined
·
1,727 Posts
Yea you will drill a hole SMALLER than the tap size. Then tap the threads by hand with the correct size tap. My EGT probe was a 1/4 pipe thread, so it was a fairly large hole. I took the manifold off, but I wasn't in a hurry. If you have any questions on tap and bit size, take your fitting for the probe to a hardware store. They can get you set up.
 

·
Registered
Joined
·
76 Posts
There appear to be a lot of theories on how to do this. Having the truck running seems to make sense. Also start wil a very small drill and work your way up. This way you produce very small metal chips that are more like dust. Chips that make there way to the turbo can't hurt it.

Other tips. Keep the drill perpendicular to the surface you are drilling. Do the same with the tap. Take your time.

Hope that helps.
John
 

·
Registered
Joined
·
376 Posts
Just a suggestion. If this is your first time using a tap, Maybe it would be a good Idea to run down to the hardware store and get a piece of flat stock to drill and tap a few times to get the hang of it before diving into the manifold.
 
1 - 18 of 18 Posts
Top