How tight should head bolts be?
In most applications it is necessary to first hand-tighten each bolt snugly until the head of the bolt is flush with the cylinder head surface. The bolts are then partially tightened to approximately half of their recommended torque loading in the order specified by the particular engine’s manufacturer.
What happens if you over tighten head bolts?
When you overtorque above 15% of recommended which in this case would be about 95 ft/lbs you basically turn the fastener into a rubber band. Some of the fasteners will stretch and you will have uneven torque. Add heat and pressure and head gasket blows and the head can even warp.
Should head bolts be replaced?
Bolts are designed to stretch as you torque them into place, and when you remove them, they snap back to their original position. Because of this, many standard head bolts are okay to use more than once, as long as they have not been stretched past their spring back point.
Do I need new head bolts when replacing head gasket?
Head bolts should be replaced when you change the head gasket to prevent bolt failure. Restretching bolts isn’t a good practice. If you don’t replace then you might as well not do the job it’s almost a guaranteed to leak. Stretch bolts give you the correct torque.
When should you Retorque head bolts?
In most cases you don’t need to retorque head bolts or studs. If the bolts or studs aren’t tight you will lose compression or get coolant in your cylinders. You can use bolts or studs based on application, but studs tend to give more consistent torque values. Never reuse Torque-To-Yield (TTY) bolts.
Can ARP head bolts be reused?
Are ARP bolts and studs re-usable? Yes. As long as the fasteners have been installed and torqued correctly, and show no visible signs of damage, they can be re-used. If they show any signs of thread galling or corrosion, they should be replaced.
Can you reuse connecting rod bolts?
Like headbolts, you can reuse rod and main bolts assuming they are in good condition. Check them for excess stretching at the threads and where the head meets the bolt shank. Bolts are inexpensive, though. If you are intending on making a lot of power, consider new or upgraded bolts/studs.
Can you reuse Arp 425 head studs?
Yes, you can reuse them. No need to send them in.
What do ARP head studs do?
Using studs will make it much easier to assemble an engine (especially a racing powerplant which must be serviced frequently and quickly!) with the cylinder head and gasket assured of proper alignment. Studs also provide more accurate and consistent torque loading.