A bottom tap should just have a chamfer on the first cutting edge. Plug tap has the first three threads tapered, and a taper tap (or starter tap) will have the first 6. To me, that pic has the first 3 tapered.

 

That would be called a #2 tap wouldn't it. and a starting tap is #1..........I'll bring it and show you.

 

bump...........for dodgediesel

 

pardon my stupidity here, Do I nned to Tap these Studs before I intall them I was Told by one person all I need to Do is install one at a time starting from the middle working my way out, Torqueing to 125lbs, And drive it for a week and re-torque one more Time and Done, nothing mentioned about tapping. I was just planning on installing these Studs I had origionally purchased for a 2-nd gen that I have since sold. And now have this 3-rd gen 05-dodge, was going to pass on the o-ringing as I here the 3-rd gens can handle a little more Boost and should be fine with just Studds. I am Running just a Single Turbo Silver-62-14 I think its waste gated at 40-45 from the factory, but was interested in cranking it up a Bit after the Stud install. ( Should I do the o-rings too is it needed in this 3-rd gen if I do just studs and maybe max boost pressure of 50?

 

You might as well bottom-tap the holes if you're going through the effort to install studs.

 

In- Regard to Bottom Tapping does anyone have a Link with Specific detailed Directions, with photos perhaps on bottom Tapping a 3-Gen with 12mm ARP Studs?

So it would be safe to say that most Guys out there Driving a Dodge with a Twinn Turbo Set-ups all have Head Studs and O-ringed Heads, But What percentage of them all have actually Bottom Tapped ?

With the ARP Studs it just recomends to use the Moly Lube and Torque to 125 or there abouts , And then Drive for a few Days / or so many miles and then re-inspect and Torque And one should be good to go, if your real cumpulsive / Obsessive you could Inpect them one more Time a week or 300 miles later. Always better to check Twice and Tighten once.

 

I'm left asking "why tap"

Am I missing something? If the stud is too long, it's a design flaw, and you can always shorten it.

If it's to increase thread engagement, I'd validate the need for more threads first-- meaning, I'd want to see a case where the threads were pulled out and the studs were installed PROPERLY.

Proper installation, imo, is just as Blackdiesel described: finger tight, minus a little bit.

But I've never studded a head, and all I have is my dern theories

 

I don't do it to add threads, I do it to chase/clean out all the gunk and goo in the holes. The stuff that comes out of there scares me

 

If it's just cleaning, I'd do brake cleaner and compressed air or something like that. Seems safer to me.

 

I plan on sending me head out soon to be O-ringed , re-surfaced, helix Cam-2 & Vavle Springs Done.
I am only going to install the ARP 12-mm Studs the way they are writtin in there instruction List No- Tapping is really re-quired ( No-Voo Doo

 

Brake clean and compressed air doesn't get out the stuff thats baked in there. If done properly,tapping doesn't cut any new threads, just cleans it out. Clean threads means less chance of picking up due to junk in there. Then comes out the smoke wrench, or drill it out if you need to remove it. Some high temp anti sieze wouldn't hurt either, I'd think.