answers to frequently asked questions
1. Does the chamfer on the washer go up or down?
The chamfered side of the washer goes up toward the head of the bolt.
2. Do I need head bolts or studs for my engine?
This depends on the installation. On many street-driven vehicles, where the master cylinders and other items protrude into the engine compartment, it’s probably necessary to use head bolts so that the cylinder heads can be removed with the engine in the car. For most applications, however, studs are recommended. Using studs will make it much easier to assemble an engine with the cylinder head and gasket assured of proper alignment. Studs also provide more accurate and consistent torque loading.
3. Do the head studs only go in hand tight?
The studs should be installed finger tight. Then, when applying torque to the nut, the stud will stretch only on the vertical axis. 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 (or bolts) are re-torqued after the engine has been run.
4. Do the lines on the nut go up or down?
The lines on some nuts are identification marks only; they can go up or down.
5. Why are my “new” head studs leaking water and how do I stop the leak?
Prior to installing your “new” head studs, it is very important that you have clean surfaces to start. First, clean all the threads in the block with a thread chaser; make sure that you go all the way to the end of threads in the hole. This will also ensure that you get full thread engagement of the stud in the block. Next, clean the threads with brake or carb clean to remove any thread sealer, lube or antifreeze that may be on the threads. Then, clean the threads on the fastener. Use a liberal amount of ARP Thread Sealer, hi temp silicone or loc-tite on the threads to ensure that there will be no air pockets which can cause leaks. Then follow the instructions for installing the fasteners.
6. Are the head bolt kits (or head stud kits) for one head or both heads?
The kits are complete to assemble the application listed in the catalog. A four cylinder or inline 6 cylinder have one head and the kit will have components for one head. A V6, V8 or V10 have two heads and the kits for these will have components for two heads.
7. Can you use loc-tite or any thread locker instead of ARP Assembly Lube?
You may use loc-tite or any thread locker instead of ARP Assembly Lube. Always ensure threads are clean prior to applying any lube product. When using loc-tite, make sure you assemble the parts before the loc-tite cures. You can use loc-tite instead of ARP Assembly Lube, but do not use them together.
8. Is ARP’s torque recommendation the same as the vehicle manufacturer specifications?
Sometimes ARP will recommend using torque specifications that are different than the vehicle manufacturer specifications, but not always.
9. What drill size do I need for my wheel studs?
To determine what drill size you need for your wheel studs, you will need to know your axle/hub material and the wheel stud knurl diameter. If your axle/hub material is cast iron/steel your drill size will be .005˝ less than the knurl diameter. If your axle/hub material is aluminum, your drill size will be .007˝ less that the knurl diameter. The Wheel Studs Section in the catalog shows the knurl diameter sizes.
10. The catalog says “U/CUT” Studs. Do I have to cut the studs?
You do not have to cut any studs. “U/CUT” means the studs or bolts are “undercut”.
