1500 head studs

[Bob Buxbaum]

More stupid questions.

The short block is built and ready for the head. I did not notice the differences in the ends of the head studs until I prepared to reinstall them. I have found that two are longer and go in the right rear corner on the block. However, not knowing the the ends are different, I did not look at them upon removal. I see that the end with about 5/8" of threads also has a vertical groove in them. My question is which end goes in the block, and is there a torque value to observe?

Second, after using Google to look into this, I saw a lot of discussion about not reusing them (for various reasons). Before I screw up, should I get new ones?

Lastly, because repair manuals sometimes are wrong (imagine that!!), what is the correct torque, and how should it be applied? (I am used to torque to yield on the few dozen BMW 3s I have built or done head work.)

P.S. I hope everyone had a wonderful Easter Sunday or Passover.

 

[Gerard]

It's generally a good practice to replace them.

Rocker pedestal to head is 32 lb/ft
Cylinder head to block 50 lb/ft (1975-76)

 

[dklawson]

While it is good practice to replace them, I would not consider it mandatory on a street engine. Look carefully at the threads for any apparent damage and necking. Definitely replace any showing signs of damage.

I thought the longer studs were for use where the lifting eyes are installed. I don't remember any difference in the ends to dictate which went into the block.

Gerard gave you the torque values. My practice is to follow the pattern shown in the manuals in three steps (i.e. All the way around at 20 ft-lb, around again at 35 or 40 ft-lb, and then finish off to the full value. Do not torque the studs into the block. They go in finger tight. Only torque the nuts.

 

[Bob Buxbaum]

Thank you both. There IS definitely a difference in the threads and thread length. As I said, the short end is threaded about 5/8th" and has a groove. The other end is almost 1" of thread with no groove.