pulsarboby said:
im not a lover of these head studs either! i cannot see the point in them tbh
the advantage of a correctly designed/installed stud over a bolt is that the studs provide a more accurate and consistent torque loading.
Using bolts to secure a head, the whole bolt, being the fastener is being twisted while it's being torqued to the correct reading, the bolt is reacting to the force being applied on it and a resistance against the threads in the block as it tightens down.
A stud should be installed finger tight. Then the torque is applied to the nut. The stud if its bottomed out in the block will not twist and can only stretch on the vertical. This provides a more even clamping force on the head.
Whats been discussed with the arps for our engine is that if there is a problem with them its due to the fact that the stud is not bottoming into the block, The chisel point of the nismo studs (rob can provide pics) bottoms out in the block so the stud cant twist when the nuts are torqued, all of the jap studs for the sr20 seem to have this design, the arps do not. Arp however stated to me that there is not a problem with their design and they will not cause any issues with head lift/gasket failure. They told me 2.5-3 times stud diametre of thread depth was adequate on an aluminium block, and the studs would not pull. However, the Arp design department also told another guy when he sent drawings for sr studs to them that they had nothing to suit the application...
and there i was saying i had nothing useful to add to this forum only yesterday :lol:
from the information i've gathered and experiences of very good engine builders any issues with the arps seem to be when people torque them to the packaging recommended 70lbft.
like allen says, cometics seem to suck on the sr20 :lol: if frank (turblio) still comes on here, his own issue with the engine that se nissan built would seem to confirm what others have been saying in the states for a while.
hks all the way 8)