Has anyone actually done this? Where you drop a couple steel ball bearings into the thread hole before installing ARP headstuds to prevent them from bottoming out?? (whew!) If so, how big was the bearing?? Supposedly this has the same effect of the AEBS headstud "dimples"....

 

I believe one of the points of using studs is that they are supposed to bottom-out. Thus, if you did this you would be reducing the amount of thread that contacted the block, effectively making them bolts, in a sense.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ion_four &raquo;</TD></TR><TR><TD CLASS="quote">I believe one of the points of using studs is that they are supposed to bottom-out. Thus, if you did this you would be reducing the amount of thread that contacted the block, effectively making them bolts, in a sense.</TD></TR></TABLE>
No actually you do not want them to bottom out that is the reason behind the dimples and/or ball bearings. Here is what is said about the AEBS studs on their site" The dimple design preloads all the threads of the stud on all the threads on the block. The dimple bottoms out first rather than bottoming out the thread of the stud."

And the ball bearing method I heard from a very reputable machine shop.

 

yes. bottoming out the threaded part will **** up the threads.
ive done it before for me

 

Yes, I cant believe that some people will actually torque in head studs.....that is just retarded.
I cant wait to get my AEBS headstuds. I hate pulling the valvtrain back apart to retorque the ARP's. Every so often I will notice they will lose a couple ft/lbs. here and there.

 

If you use this trick, you would probably want to use only ONE ball bearing probably about 1/4" diameter. I have never had the nerve to try it, however.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">If you use this trick, you would probably want to use only ONE ball bearing probably about 1/4" diameter. I have never had the nerve to try it, however. </TD></TR></TABLE>

any updated info/experience on the size and type of ball bearing(specific metal), and whether or not I should have the nerve to do it in my build up?

 

The AEBS studs are supposed to be torqued in, but just a little bit to preload them. Here are some nice pics I took for u guys.
Here is a pic of how tight the GE ls/vtec dowel pins fit over them.





The hex hole cut in the top of the stud is for preloading.

 

I assume that there is some kind of problem with Honda threads not extending all the way to the bottom of the stud hole?

Just use a bottoming tap in the proper size to clean out the threads and extend them to the bottom of the hole.

The reason to use studs is so that they bottom out. By bottoming out a stud (bottoming out the stud itself, not the threads) you load the threads in the OPPOSITE direction that they will be loaded when you torque the nut down on them. That way, in the end, the total stress on the stud is less than it would be with a bolt.

Just thought you guys might want to know the reason behind the madness.

 

Are u sure about what u just said?? The dimples will bottom out and push the while stud up against the threads in the head. When u torque the nuts down it will pull on the stud and push the head down on to the block. Preloading will load the studs in the same direction as the nuts will. Only way to lead it in the opposite direction would be to push down on the stud. Am I right or wrong?

 

With dimpled stud ends, arp says only about 5 lbs max of tightening. Over tightening puts stress in the wrong places. You don't want the threads fighting against each other.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by leadfoot78 &raquo;</TD></TR><TR><TD CLASS="quote">Are u sure about what u just said?? The dimples will bottom out and push the while stud up against the threads in the head. When u torque the nuts down it will pull on the stud and push the head down on to the block. Preloading will load the studs in the same direction as the nuts will. Only way to lead it in the opposite direction would be to push down on the stud. Am I right or wrong?</TD></TR></TABLE>

i came up with the same mental picture^ Seems like thats how it would work to me.

 

Nope, I'm sure I said it right.

When you tighten it down so that it botoms out, you put the stud in compression. Then, when you tighten the nut, you stretch the bolt back out. However, it has to decompress before it can start to be stretched.

Make sense?

 

Nope, sorry. I don't understand what u are saying. When it bottoms out the force behind the 5lbs will load the threads upwards, just like tightening down the nut. The only part under compression will be the dimple and beyond the bottom thread the stud will not be under load, then torquing down the nut will stretch the stud. That's how I see it. Maybe Earl could explain this. I think Earl should have a title "The all knowing H-T God" hey it's better than mine.

 

My ARP's had a lip at the top of the threads. The lip prevented the threads from bottoming out in the holes. I torqued mine to 20ft/lbs. Then torqued the head to 78ft/lbs....

 

Man, you're hard to convince.

Here is a direct quote from "Maximum Boost":

"When a stud is torqued up, the shank bottoms out on the chamfer. The stud's threads pull on the shank, inducing compressive stress in the surrounding base metal. An upward force applied to the stud pulls the compressive stress back to zero before inducing thensile stress, resulting in lower net tensile stress.

The stud, and the metal in the head below the stud, get "squished" when you screw it in. Then, when you torque the nut on, it pulls the stud back up. The stud starts to stretch, and it also releases its pressure on the bottom of the hole.

 

corky bell is talking is talking about bottoming out the shank not the tip of the stud. (pg 161 Max boost). I guess it works the same as bottoming out the tip of the stud though.

It still seems to me that if you bottom out the tip and continue to torque it the threads in the block will be pushed up (contact on the under side of the block threads) by the threads on the stud. Then if you put the head on and torque it the nut will pull in the same direction.... someone please explain how these loads can cancel out!

 

It's not the load on the threads that we're concerned with, it's the load on the actual stud itself, and the load on the metal in the head.

This helps to lessen the net stress on the stud, and helps to keep the head from distorting.

 

OT: what do you do if you strip a thread? I know they *usually* put in helixcoils(sp?) but those come out quite frequently.

But a guy at a local machine shop near me said they have something new out that works great... forgot what it is though.

 

I've never stripped a head stud thread.

If you clean them out with a tap before you install the studs, and lube the studs properly, I doubt you will ever have a problem. Those things are beefy.

 

So what size tap is necessary?

 

I've never stripped a head stud...By buddy did once at his shop changing a head gasket - the threads came out with the bolt...he just helicoiled it, but that was on a stock integra.

I've always made sure my ARP studs are Right at the bottom (lock 2 nuts together on teh top and screw the stud all the way in till it makes contact at the bottom - don't torque it down, just make it tight enough that you can't back the stud out with your hand). As a result - I have NEVER had a stud back out on me, and some of the motors i've built have been running for 3 years, and some are running 15+ PSI.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by racinskittle &raquo;</TD></TR><TR><TD CLASS="quote">OT: what do you do if you strip a thread? I know they *usually* put in helixcoils(sp?) but those come out quite frequently.

But a guy at a local machine shop near me said they have something new out that works great... forgot what it is though. </TD></TR></TABLE>

timesert

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kpt4321 &raquo;</TD></TR><TR><TD CLASS="quote">It's not the load on the threads that we're concerned with, it's the load on the actual stud itself, and the load on the metal in the head.

This helps to lessen the net stress on the stud, and helps to keep the head from distorting.

</TD></TR></TABLE>

aren't the threads part of the stud and block.

I get what the goal is - to preload the metal in the opposite direction so when it is in use the assembly is under less stress- I just don't get how you do that by bottoming out the stud. I need a better diagram than the one in maximum boost i guess

 

Ok, I think I know what he is saying. Seams like u have to think about the stud as it was two diff parts. The inner stud and the outer layer which includes the bottom and the upper threads. So preloading will pressure the inner stud up and stretch the lower threads down, and the nut will pull up un the threads to even out the stress with in the stud. That's the only way I can make sense out of that, and it still seams a little far fetched.