12mm Head Stud/Valve Cover Interferance?

4x4dually

4x4dually

Moderator
I have heard that when putting a set of ARP 12mm head studs in that a slight modification has to be made to the valve cover. Is this true and does anyone have detailed info or pictures of what I will need to do? Any info would be greatly appreciated.
 
nope, but it does require some work to be done with a bottoming tap. the threads are not tapped to the bottom of the holes, so the stud wont go all the way down. its usually only the 2 on the very front of the head.

i bottom tapped mine and it was no where near interfering with the valve cover. I have 2 bottoming taps from when i did mine, let me know if you need to use one and i can mail it to ya.

its harder to tap with the head on because you need a LONG tap handle, i did mine with the head off the truck.
 
4x4dually said:
I have heard that when putting a set of ARP 12mm head studs in that a slight modification has to be made to the valve cover. Is this true and does anyone have detailed info or pictures of what I will need to do? Any info would be greatly appreciated.
Click to expand...

Yeah on some engines the holes aren't tapped deep enough and the stud will not thread down far enough,thats why they recomend tapping the holes but if your heads not off it's hard to do.But usually the ones in the front will hit the bottom of the cover, but all engines are different you might not have a problem
 
Well hell, who the heck told me that you could just "swap them one at a time, it is easy". :kick: No one said, "O, you have to do some tapping and other junk." LOL I guess I should get ready. Where the heck do I find a tap that I can use that is long enough to do it with the heads on and in the truck? You said the front two holes are the only ones I need to tap or do I need to run all of the holes? I guess the holes in the back of the head are not going to get run?
 
What are the specifics on the tap? If I had to buy a long one, what should I ask for when I call the local "screw guys"? 12mm bottoming tap with a 12 inch shaft? Sounds familiar! LOL
 
We've not had problems on the 24v's as long as you check the clearence on ends of the valve cover. Sometimes those need 1/16" taken off the cover to clearance them. Vacuum out the holes too. The rocker pedestals or the valve covers or the studs need to be modified for hte 6 long bolts on the 12v.

brnaodn.
 
Happy reading, see attached. I'll be doing mine later this week. McMaster-Carr can get you your bottom tap.
 

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According to several folks I have talked to valve cover clearance is not a big issue on the 24V like it is on the 12V. I personally don't know but will take their word on it, I do hope to be finding out for myself shortly though :evil
 
Thanks for the info guys. I guess I should make sure that when I buy them, that they are the 'updated' kit so I don't have trouble. Satburn, let me know how your install goes later this week. I wish I could stand around and hand you tools so I could see first hand how to do it, but I don't think the 6 hour drive and a couple tanks of fuel would be worth it!
 
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