Bottom Tapping Head Stud Threads????

[dodgediesel]

Is this a real benifit? Most people say to bottom tap, install studs and then back the studs out a 1/4 turn before fully torqueing. I bottom tapped one so far and when I back the stud out 1/4 turn, the threads seem more sloppy than the one's I havent bottom tapped yet. Should I be worried about the studs stripping out if I continue with the rest? Also, why doesn't a guy tighten the studs in completely to prevent them from slowly wiggling back out or could that ever happen??? I'm just trying to get all the information now so when my head gets back from being o-ringed, I can be ready to do it right this time..

[97' CTD]

I bottom tapped all mine working good so far.
Brandon

[dodgediesel]

Did you back the studs out 1'4 turn prior to torqueing them?

[blackdiesel]

I didtn bottom tap either trucks that i installed studs on. (two different rigs)

backin the studs out 1/4 to 1/2 of an inch allows the nut to properly clamp down on the head. As opposed to the stud bottoming out and decreasing the clamping ability of the studs.

It makes sense in my head, just not sure if i explained it good enough. Somebody get HOHN in here

[dodgediesel]

Blachdiesel, are you o-ringed?

[97' CTD]

Yes, I backed them out 1/2 turn. I look at it this way you are this far do it should be no question. Im O-Ringed.
Brandon

[PourinDiesel]

If you bottom tap you'll never have to "back the stud out" because you'll have extra room with the new threads.

Not bottom tapping your wasting your time using studs.

[dodgediesel]

Sorry to ask again but I want to get it right. So bottom tap and back them out 1/4 turn or bottom tap and tighten studs? I'm just afraid of having these wiggly head studs after I bottom tap them, it seems to really open up those threads. I have the correct tap size. Am I worrying too much???

[blackdiesel]

No, im not ringed, but im also just running a smarty. Back in the day i was pushing 45 psi and 530 hp, so i studded the head.

If it makes them sloppy, i wouldnt bottom tap them. I can see the benifits, but they just dont justify the work. (IMHO)

[Tate]

If you turn the studs tight against the bottom of the block, you are already putting stress on the threads in the block before you've even began to tighten them. Different expansion rates of materials could make this even worse. Make it much easier to pull the threads out of the block.

[PourinDiesel]

Originally Posted by dodgediesel

Sorry to ask again but I want to get it right. So bottom tap and back them out 1/4 turn or bottom tap and tighten studs? I'm just afraid of having these wiggly head studs after I bottom tap them, it seems to really open up those threads. I have the correct tap size. Am I worrying too much???

If your making the threads sloppy then something is wrong. With the proper tap you should just be making new threads and thats it.

[blackdiesel]

I put in one set of schieds studs for a guy, and their not ever threaded all the way to the bottom of the stud. the last 1/4" is just a little ball. You can go to their web site and see them. So bottom tapping would be worthless if you use theirs.

[CTD01]

when u bottom tap with a good sharp tap it will cut to much meat out.then u r risking pullin the threads out of the block. when i did mine i just used a little oil and screwd them in and backed off a 1/4.

[XLR8R]

To the OP - how hard did you hit the bottom of the hole with the tap? A quarter-turn too far can cause the thread tolerance to balloon.
Did you hit a clean (chip-free) bottom and back out the tap a few times on the way down to break the chips?

Like Justin posted, a properly tapped deeper hole will result in less stud "wiggle".

[Jfaulkner]

Originally Posted by CTD01

when u bottom tap with a good sharp tap it will cut to much meat out.then u r risking pullin the threads out of the block.

You've got to be kidding me! Unless your using the wrong tap (standard tap in metric hole, or wrong thread pitch) the correct tap will only remove material from where there aren't already threads.

Bottom line is if your using ARP studs, bottom tap them. If ARP didn't believe that the studs needed to be that long don't you think they would have saved material and the production time cutting the threads that long? Keep in mind shortcuts can lead to problems later. Ask Navistar how well the decision to only use 4 headbolts per cylinder on the 6.0L instead of the 6 everyone else uses. You could get away without doing it but then again you also could get away with only using 2 lugnuts per wheel. It's your truck.