Why 6bolt head studs in a 7bolt head/6bolt block swap?

[danymuck]

Why can´t I use my ARP 7 bolt head studs in this swap? What kind of issues?

 

[snowborder714]

Won't fit in the holes in the 6 bolt block (too small).

 

[Colt4G63 also]

Why can´t I use my ARP 7 bolt head studs in this swap? What kind of issues?

Mostly things like the studs won't thread into the block at all because of a 2mm difference in size.

 

[danymuck]

What? I fitted my ARP head stud 7bolt In this block already.

 

[snowborder714]

6 bolt blocks use a 12mm head stud while 7 bolts use an 11mm head stud. Not sure how you did that unless they were loose going in and you didn't know it or you really don't have a 6 bolt block.

 

[danymuck]

The studs were loosing when i fitted until I tight them, then the studs were tight.

What kind of issues I´ll have?

Sorry for my english

 

[snowborder714]

When you say they were loose, do you mean left and right wiggle and/or up and down pulling? If so, that should've indicated right away that they weren't meant for that hole.

By tighten them, do you mean install head, then nuts, and torque? Or did you use an allen key in the top of the head studs to tighten them (not supposed to)?

What could happen? If you even start to lift the head a bit, the studs could rip the threads out of the holes and have the head completely come off the block.

 

[danymuck]

I used an allen key in the top of the head studs to tighten them. And yes, I mean left and right wiggle.

But I have ARP stud with nuts. Anyway in the same trouble?

 

[snowborder714]

If you noticed left and right wiggle, you should've stopped. You need to remove them, hope you didn't mess up the block threads, and purchase the correct studs.

It's my understanding (never actually installed ARP head studs) that you're to tighten the studs using your fingers and not really wrench on them with an allen key.

 

[Cdc1221]

^yes. My 6 bolt ARP studs didn't even have provisions to use a Allen wrench. Install finger tight and go

 

[WES_393]

^ You sure they weren't just upside-down?

I've always started the studs by hand first, but then used an allen wrench to speed up the process. Once the stud bottoms out just back it out 1/4 of a turn or so.

 

[Jward5]

I thought the treads in the block where the same but the holes in the 7 bolt head are just a smaller diameter?

 

[pauleyman]

No. The holes in the block and the head are both different.

 

[WES_393]

The 7-bolt stud/bolt is 1mm smaller, which is why the holes through the head are 1mm smaller.

 

[danymuck]

Then....I need to drill my head holes to 13mm, right? 1mm more diameter?

 

[Purple_Demon]

.500" or just over 12mm I think....

BogusSVO or someone had a thread on it a while back. Try digging through the tech forums and it should pop up fairly quickly.