Stupid Studs...

wildmanben

wildmanben

Farmboy...
So Josh and I are putting his head back on after the long wait of finding a new head and having it o-ringed. Anyways, tapped the holes, blew the crap out, prepped the surface, got the head on and torqued the ARP 12mm studs. 25, 45, 90, 125. And for the bad now. 6 studs pulled out of the block at about 110-115ft/lbs. We used a moly lube on the threads and washers. Nice steady pull then crack and its downhill from there. What the heck.

So what do we do? Pull the head and get another gasket obviously. Do we drill the holes out and helicoil them? Will that hold? Or do we drill and tap all the holes for 14mm studs? Who's to say that if we repair the bad ones that more may do it at a later time during a re-torque?

When we pulled the studs out originally, they were all rusty and the holes were full or crap and oil and such. Cummins did a great job the first time on this. Not... Would the rust weaken the threads that much? I just dont get it. Where did we go wrong? Did everything by the book. Did the same thing to my truck and its holding up just fine. What gives?
 
That really sucks. At that point I would drill and tap for 14mm, you might as well start with fresh treads.
 
6 of them pulled thru? That is messed up. I have installed several sets and never had one do that. Are you sure your torque wrench was accurate? I am just wondering if the wrench was way off and you where putting more torque to them than you thought? At this point I would say go with 14mm studs. One thing you have to keep in mind is that the bushings used to line up the block and the head are larger on the 14mm studs so you need to machine those holes larger also. Sorry to here this happened. Good luck on the rest of your build.
 
yah his torque wrench was balls on (snap on self-calibrating torque wrench)
i just realllllllly dont want to have to drill, and tap 26 holes for those stupid studs when i already have those 12mm ones.
even if we do end up drilling the holes, how do you manage to drill the back holes at a good angle without pulling the motor?
also, the head gasket, should i just turn that into a 100 dollar poster for my room and install a new one?
 
Damn that really suckz. At this point your only choice is to re-drill, re-tap to the bottom and 14mm's.... Sorry to hear of your troubles.:bang
 
I second the no!

But I vote using a heli-coil. We've used them a in the past on applications that require a lot more torque than our little Cummins, and have never had a problem when done correctly!

Chris
 
Signature600 said:
I second the no!

But I vote using a heli-coil. We've used them a in the past on applications that require a lot more torque than our little Cummins, and have never had a problem when done correctly!

Chris
Click to expand...

I would not heli-coil a block. I don't have a good reason, just doesn't sound very good to me.

Pull the motor and re-drill and tap for 14mm studs.
 
Like I said, we've done it on MANY Deutz and AC engines. The Deutz's torque to 119ft lb, then another 270*, so they will hold some torque!

I've also heard Don M tell people to heli-coil them! Either way, you're getting new threads in the block...at least in my mind!

Chris
 
Signature600 said:
\

I've also heard Don M tell people to heli-coil them!

Chris
Click to expand...

Well heck, order up some Formula 1 heli-coils, it should give you at least 40 more hp. :rolleyes:
 
When a prostock team gets a new block what's the first thing they do with it? They heli-coil all the head stud holes. Heli-coil + stock block material will hold more clamping force than the original block material because of the larger heli-coil thread engagement.

brandon.
 
So I would imagine we would need to do them all? Would I stack 2 coils on the holes then? Thats a lot of helicoils...
 
Signature600 said:
Nice way to be helpful;) Would you rather Compy said it?

Chris
Click to expand...

Well..it depends...do you want 40 more horse, or revgain?

And I always try to be as helpful as possible. LOL
 
wildmanben said:
So Josh and I are putting his head back on after the long wait of finding a new head and having it o-ringed. Anyways, tapped the holes, blew the crap out, prepped the surface, got the head on and torqued the ARP 12mm studs. 25, 45, 90, 125. And for the bad now. 6 studs pulled out of the block at about 110-115ft/lbs. We used a moly lube on the threads and washers. Nice steady pull then crack and its downhill from there. What the heck.

So what do we do? Pull the head and get another gasket obviously. Do we drill the holes out and helicoil them? Will that hold? Or do we drill and tap all the holes for 14mm studs? Who's to say that if we repair the bad ones that more may do it at a later time during a re-torque?

When we pulled the studs out originally, they were all rusty and the holes were full or crap and oil and such. Cummins did a great job the first time on this. Not... Would the rust weaken the threads that much? I just dont get it. Where did we go wrong? Did everything by the book. Did the same thing to my truck and its holding up just fine. What gives?
Click to expand...
You most likely damaged the threads in the block by trying to bottom tap them. Tapping can be risky with the motor still in the truck. The studs will go in deeper than the bolts you took out and bottom tapping is not needed.
I would install heli-coils but take the block out to do it. They need to be straight.
 
Billyram said:
You most likely damaged the threads in the block by trying to bottom tap them. Tapping can be risky with the motor still in the truck. The studs will go in deeper than the bolts you took out and bottom tapping is not needed.
I would install heli-coils but take the block out to do it. They need to be straight.
Click to expand...


so what your saying is when a person goes to install head studs they don't need to bottom tap because the studs will go deeper anyways??? what about cleaning out the original threads
 
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