head bolts vs studs

[brownfish]

I am putting new head gaskets on a 2001 200 EFI Mercury. The heads have a note cast into them that says not to re-use the head bolts. The note says to torque new bolts to 30 lb./ft. and then 90 degrees. I am considering going with grade 8 studs instead of bolts. Does anyone have a swag at what the proper torque would be on oiled, fine-thread studs?

 

[Silvertip]

Re: head bolts vs studs

The 90 degree turn after reaching a specified torque provides for a controlled amount of bolt stretch. Changing grades of bolts would upset that but I would suspect you could use the same torque figure but skip or at least reduce the 90 degree turn to say 45 degrees.

 

[j_martin]

Re: head bolts vs studs

Buy new bolts and torque them to specs. There's a reason why it's that way.