What does a stud do that a bolts won't? This is for N/A motor......


Same question for main bearing caps.......I know they are better but why?

 

studs hold torque better and you can use them as many times as you want and they'll never get weak.

I used studs in my head and mains on my turbo 4 banger, but I wasn't going to do that with the Z28. Just seemed like a PITA to get the valve covers on with studs in the way.

I would trust ARP head bolts over 500 HP.

 

The studs dont stress the threads in the block as much as bolts do. When torqueing downs bolts there is friction, heat and stress at the point that the block threads make contact with the bolt threads. Studs only encounter this on the stud itself and nut which are going to be mega hard. I installed studs on my new motor in sig at the suggestion of the builder who swears studs are much better than bolts.

This was copied from ARP site:
Studs also provide more accurate and consistent torque loading. Here's why. When you use bolts to secure the head, the fastener is actually being "twisted" while its being torqued tot he proper reading. Accordingly, the bolt is reacting to two different forces simultaneously. A stud should be installed in a relaxed mode - never crank it in tightly using a jammed nut. if everything is right, the stud should be installed finger tight. Then, when applying torque to the nut, the stud will stretch only in the vertical axis. Remember, an undercut shorter stud will have a rate similar to a longer, standard shank stud. This provides a more even clamping force on the head. Because the head gasket will compress upon initial torquing, make sure studs and bolts are re-torqud after the engine has been run.