27 replies to this topic

[KJM]

Do you know if the block has ever been skimmed? That would seem to be the logical explanation.

I very much imagine is has been skimmed as it has had a lot of work over the years. However, a normal stud set doesnt have any threads sticking out!

[gazza82]

But they probably don't go right to the bottom of the thread holes either .. the originals look a few mm shorter in you pic which is still short enough with a chunk off the block.

[InnoCooperExport]

my block was skimmed and I fitted a set of ARP studs but didn't have any threads sticking out. They threaded right down to the bottom, easy peasy.

[grizzler73]

Have you stuck a vernier down the holes to measure them? Seems odd that they don't thread all the way down.

[Steve220]

I'd measure with a vernier and compare it to how far the stud is going down. I still reckon the threads are corroded down the bottom and need clearing with a plug tap rather than just a thread cleaner.

[johnR]

Surely as long as the threads go in as far as the original ones did the studs will do the same job and it's just the look of it that offends? The only issue would be if it lead to a clearance problem at the top. As the studs are only hand tightened it's not as though the friction of the wider part of the stud at the top of the thread against the block is critical? 

[Spider]

Advice from ARP on this;-

 

"Do the head studs only go in hand, or finger tight?

Yes, cylinder head studs are installed only hand tight. Other than the use of an allen wrench on the hex broached into the end of the stud (to ease installation, not to apply torque), use no tools to seat them in the block. However, it is extremely important to ensure that the studs are fully bottomed out in the hole in the block and not hung up on damaged or corroded threads in the block preventing the stud from being fully seated. This is often indicated when the stud threads extend past the deck surface."

 

(the bolding and underlining here is mine)

 

http://arp-bolts.com/p/FAQ.php

 

I can see there are many reasons for this, one is that but not having enough thread engagement in to the block, more stretch will be in the engaged UNC thread than the stud was designed for.

[grizzler73]

I measured the depth of the stud holes in a block I have that has never been skimmed, they measure an average of 26.5mm deep. Hope that helps.
Simon

[nicklouse]

If the studs are seated on the bottom of the holes there is no issue.

[panky]

Is there any problem with cutting them down to the same length as the original studs? as they screwed all the way in.

[InnoCooperExport]

I think you might find that the original studs didn't so much screw "all the way in" as much as that they "went in as far as they would go". Break out the measuring sticks (i.e. vernier calipers) and measure the depth of the hole, it will tell you much more. 

 

You could cut the threads shorter but I would advise against it. For one they're tough as old boots and most of all it won't fix the root cause of your problem. Get it measured and see what's going on down there. I'm confident you could run a decent tap down it, clean it out properly and then fit the studs as they're meant to be fitted. 

[Northernpower]

I can't see anywhere on the thread if you've measured the depth of the hole in the block compared to the length of the thread on the stud, also, is the problem the same with all the stud holes?

[racingbob]

didn't know you only put the head studs in finger tight have always gave then nip with 2 head studs never been a problem even on my race mini