QUESTION . . . When using Head Studs on an LS block ( iron LQ4, in this case ), instead of Bolts, what is the correct Torque Spec, since Head Studs don't "Torque To Yield" ?

Thanks, in advance !

 

Studs are screwed into the block hand tight. Thread sealer on any stud that goes into a water jacket. Nuts are tightened to stud manufacturers spec. Dry torque, oiled torque and moly lube torque is all different.

 

Since the studs are, initially, only "hand tight", I presume that they are, in fact, "torqued", when the nuts are torqued to final specs . . . Right ?

 

The studs never tighten downward into the hole. The nut pulls on the stud from the top side and stretches it up.

 

The sounds to me like both the threads on the stud and the nut should be "chased", prior to assembly, as the nut might "grab" the stud during installation ?

 

Oh, hell no. Don't touch those beautiful, perfect, brand new threads in your expensive ARP stud kit. What's the matter with you?! The instructions said dab the nut with grease.

Do clean up the holes in the block. You can chase the iron block threads if rusty. I'd be extra careful with the aluminum block threads though. What I did with my aluminum block was run a plastic rifle brush down the hole.

My block had drained oil for a year so I was able to flip it upside down (without making a huge mess) and spray Brake Clean and compressed air in the holes to get the crap out of it. If you can't flip the block then you're going to have to blast some compressed air in the holes. Shield with a rag so liquids don't splat everything in sight. And cover all the cylinders so debris doesn't land in there either.

Lastly, I dropped Q-tips in the holes to soak up whatever coolant and oil was left over. The studs create a water tight seal, so any water in the bottom of the holes has nowhere to expand when the engine gets hot and the trapped water will literally crack the block.

 

Also want to make sure you realize there is a difference between chasing threads and cutting threads. A thread chaser doesn't form new threads, it just cleans up what is there. A thread cutter can easily cut a path of its own to make threads and you shouldn't run one down the hole. Try to preserve the original GM thread profile that was made using much higher quality tooling than what most of us have in our garage.

 

I won't even "breathe on them" . . . LOL !

My block is a brand new, cast iron LQ4 block.

That part about liquids left in the bolt holes in the block really "got my attention" !

Thanks !

 

Thanks for the "heads-up" . . . I had no intention of using a "Tap & Die" on anything, but appreciate all guidance !

Since my block is brand new, should I still "chase" the threads in it or just clean them out ?

BTW - I am also considering Main Studs ( for "peace of mind" ) . . . No, I'm not going to "mix up" the Main Caps - LOL !

Thanks !

 

I doubt you need to. GM does a really good job on their blocks and in normal production they would go right on the line and have their guts installed. It certainly wont hurt, especially if the block wasn't properly covered during transport. I often have to chase threads on aftermarket parts (Even AFR), the OEM stuff seems pretty solid.

 

Good to know . . . I guess the term "finger tight" got me "spooked".