FYI ARP Head Studs for Iron Heads outer studs under valve cover too long.

turbo nasty

turbo nasty

Turbo Dojo / MNTR
Joined
Jul 19, 2001
A heads up on the kits....several friends have popped their headgaskets from this issue. And while building my new motor I discovered the same.

Issue is the outer 2 studs that are under the valve cover (the mid length ones/2 per bank/4 total per kit) are a little to long.

With the studs screwed all the way in the shoulder of the stud is just under the bolt hole surface so when the gasket crushes and the fastener stretches you are torquing the nut onto the shoulder more than the head.

Adding one washer per bolt will give your the clearance needed for things to work properly.

With thinner headgaskets, heads shaved, etc etc will make this worse even bone stock untouched doesnt give much. RJC, Cometic and FP9441's gaskets have all failed due to this.

Easy check...........screw the stud in and see where the shoulder is ......pretty straight forward there isnt much room at all to allow for strecth and Gasket compression.

Doesnt do much good running studs if you arent getting the clamping force in ever place. And why flirt with disaster

Here are the specs on the washers they come in single, pair or 10 per package. Bought mine from Jegs as they were the cheapest.

Washer - w/o I.D. Chamfer 7/16'' Inside Diameter
13/16'' Outside Diameter .120'' Thickness
 
True statements for sure. I have been double washering for years. Stud/bolt grip length needs to be verified on every fastener we install. I just had an issue going from a StageI to a StageII on-center block with TA heads using the supplied ARP studs. Worked fine on the StageI, but for some reason not the StageII for the two long center studs. Ended up having to use bolts in those two locations, as that was the only fasteners I had in the correct length. (gave me better clearance under the rocker pedistals, too, which was a problem on the StageI combo)
 
thanks for information !

can i simply add a washer and retorquing 2 nuts bolt side ?

i have a 86-87 stock style

claude
 
Turbo Nasty.....I am a little confused:confused:

I just rebuilt my engine earlier this year and this time went with ARP stud kit and maybe to just not knowing I did not see any issue.

I am not quite understanding what you describe.......in my mind if the stud is a little too long I dont see how that would be a problem in clamping.........

Do you have a pic?

I am lost at the point where you say "the shoulder of the stud is just under the bolt hole surface" to me this would indicate the stud being too short:confused:

At what point on the stud is considered the shoulder? I understand the "shoulder" on a bolt but the stud is threaded all the way up.

This is a concern to me I am running a 109 and stock ported irons with FP9441 gaskets and an ARP stud kit, I have not had any issues but that does not mean I feel comfortable with it with what you are describing.

Please try to explain or post a pic for me.......I may just be having a "Du-mass" moment but I dont understand.

Thanks:cool:
 
Just a follow-up on this, since I installed these last summer before this thread was published...

Is there a way to tell if your nuts are bottomed on the shoulders without removing the nuts? Maybe somebody can count how many threads are exposed above the nut when the nut bottoms on the shoulder of the stud?

If I think my nut is bottomed, is it possible to remove the nut and install another washer without disturbing anything else? I haven't driven the car very much since the head gasket swap, since it's been in the paint shop since October.

I did pressurize the cooling system with a cooling system tester after I was done installing the head gasket, and I didn't find any leaks. Not sure if that is proof that the nut is not bottomed on the shoulder.

Thanks,
 
mgmshar said:
Just a follow-up on this, since I installed these last summer before this thread was published...

Is there a way to tell if your nuts are bottomed on the shoulders without removing the nuts? Maybe somebody can count how many threads are exposed above the nut when the nut bottoms on the shoulder of the stud?

If I think my nut is bottomed, is it possible to remove the nut and install another washer without disturbing anything else? I haven't driven the car very much since the head gasket swap, since it's been in the paint shop since October.

I did pressurize the cooling system with a cooling system tester after I was done installing the head gasket, and I didn't find any leaks. Not sure if that is proof that the nut is not bottomed on the shoulder.

Thanks,
Click to expand...

Should be no problem removing just those nuts and putting the extra washers in.
 
Does anybody have a set of these studs handy (not installed)? If so, can you run a nut down onto the medium-length stud until it bottoms on the shoulder and count how many threads are exposed above the nut? I really don't want to remove any of the nuts on my car unless I'm pretty sure the nut is bottomed - don't want to risk breaking the thread sealant in the block or having the four suspect nuts torqued differently than the others.

Thanks,
 
can you be specific as to exactly which studs are the culprits via a pic of a cylinder head pointing out the 2..thankyou
 
black-is-back said:
can you be specific as to exactly which studs are the culprits via a pic of a cylinder head pointing out the 2..thankyou
Click to expand...

I don't have a picture, but I do have this sketch (my apologies to the gnttype.org web site)...

Intake Side
---------------------
| 6 1 3 7 |
<Front of engine | Cylinder Head |
| 8 4 2 5 |
---------------------
Exhaust Side

I don't have my car handy, but I'm 99.9% sure that studs 8, 4, 2, and 5 are the short ones (the ones not under the valve cover). Studs 6 and 7 are the medium ones. Studs 1 and 3 are the long ones. Studs 6 and 7 are the ones in question. I did notice that after torquing all of the nuts down, there were significantly more threads sticking out of studs 6 and 7 than the others. It never occurred to me that the nut may have run all the way down to the point where it was bottomed on the shoulder of the stud.

Can anybody answer my question above? On the medium studs, when you run the nut down until it bottoms on the shoulder of the stud, how many threads are protruding through the top of the nut?

Thanks,
 
Here's another attempt at the sketch, hopefully the formatting will remain correct this time...

Intake Side
-----------------------
6 1 3 7
<Front of Engine Cylinder Head
8 4 2 5
-----------------------
Exhaust Side
 
OK, making an ASCII sketch is not working. I found this little sketch on the internet...

0996b43f80208e8f.jpg


Sorry for my previous attempts. Again, locations 6 and 7 are the problem children.
 
As mentioned in the original post...under the valve cover (actually under...meaning unbolt the VC) there is 4 studs....the outer ones are the mid length.

Bottom line if you have studs and don't have 2 washers under each nut on those studs then you need them ASAP!!!'
 
mgmshar said:
Does anybody have a set of these studs handy (not installed)? If so, can you run a nut down onto the medium-length stud until it bottoms on the shoulder and count how many threads are exposed above the nut? I really don't want to remove any of the nuts on my car unless I'm pretty sure the nut is bottomed - don't want to risk breaking the thread sealant in the block or having the four suspect nuts torqued differently than the others.

Thanks,
Click to expand...
see above post
 
I remember seeing this posted awhile back for Champ iron heads, so does this apply for any iron head or just the aftermarket heads?
 
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