Ok guys whats the difference between the Head Bolts and Studs not Physical but which is better and why? I am replacing the head and head gasket (stock) on my car and want to use ARP when done but need to know which ones to get.
Arp Head Bolts or Studs?
- Thread starter mcpcola
- Start date
I'm sure the pros will be around soon, but this is what I have learned from my own research.
The studs are able to tighten more than the bolts (they have threading on both sides?) correct me if i'm wrong.
Added note: You're replacing the head and gasket, spend a couple extra bucks and get a metal head gasket. You won't regret it if you do, but will regret if u don't, unless you are running totally stock and never run your car hard.
The studs are able to tighten more than the bolts (they have threading on both sides?) correct me if i'm wrong.
Added note: You're replacing the head and gasket, spend a couple extra bucks and get a metal head gasket. You won't regret it if you do, but will regret if u don't, unless you are running totally stock and never run your car hard.
Here's the difference:
Bolts are ok obviously since Toyota uses them factory, but they're cheaper than the studs and easier to make so that's also why they do it. When you torque down a bolt the friction in the threads causes the bolt to give resistance, and that may lead to somewhat less accurate torwue readings. Example, you torque it down to 80lb/ft but it's really only 76 or 74 because as you tightenned it the bolt's resistance in the threads as you turned it made the torque wrench think it was tighter than it was.
Studs are better because you tighten it finger tight, so it's already tight before you even begin to torque it down, so this means the torque reading you get is more the actual clamping force on the head, and not so much the torque on the threads of the stud into the block, which isn't what you're trying to measure. Example, it'll read closer if not exactly what you wanted to torque it down to, assuming your wrench is accurate and properly calibrated.
eric
Bolts are ok obviously since Toyota uses them factory, but they're cheaper than the studs and easier to make so that's also why they do it. When you torque down a bolt the friction in the threads causes the bolt to give resistance, and that may lead to somewhat less accurate torwue readings. Example, you torque it down to 80lb/ft but it's really only 76 or 74 because as you tightenned it the bolt's resistance in the threads as you turned it made the torque wrench think it was tighter than it was.
Studs are better because you tighten it finger tight, so it's already tight before you even begin to torque it down, so this means the torque reading you get is more the actual clamping force on the head, and not so much the torque on the threads of the stud into the block, which isn't what you're trying to measure. Example, it'll read closer if not exactly what you wanted to torque it down to, assuming your wrench is accurate and properly calibrated.
eric
i dont care what anyone says... bolts stretch studs dont....thats why bolts require retorque and studs dont. get the studs they are only like 20ish bucks more.
one more vote for the studs here. they you dont have to overcome the friction of them turning in the block when you tighten them, = more accurate torque readings, AND you dont have to re-torque studs, AND they're better. 
-shaeff
-shaeff
i love studs as much as everyone else but something you should think about is if you are going to pull the heads again while the engine is in the car it may be a bitch. with the studs in the block the head can not be lifted off the block, it hits the firewall. but other than that studs all the way.
i say use the same torque. as far a 6 or 12 point, i think you can order them right from arp in either style.
No idea if they make a 6pt...I've got 12 pt.
I'm pretty sure they all come with an allen wrench hole in the top so you can get them out with the head still on.
I'm pretty sure they all come with an allen wrench hole in the top so you can get them out with the head still on.
N
NDBoost
Guest
my papers from ARP studs said 80lbs....but I've heard of people going way over that (100+??) don't know how safe that is
i like studs better because getting the head bolts out i stripped an allen head...and had to drill it out. i like the bolt top much better. and its practically strip proof with 12 points
okay, so...
What is this 6 or 12 style, is that the number of shoulders on the nut?? So does this mean that I will have to get a special socket for them? If so, what size?
Also, so I can torque them down to 100+ ft. lbs. when i lubricate the threads on the stud with engine oil? But not when I use the supplied lube? Can I use both?
As far as the torque specs, what is the optimum amount? Obviously, I don't want another BHG... So, the more torque, the better, right? What does everyone recommend?
What is this 6 or 12 style, is that the number of shoulders on the nut?? So does this mean that I will have to get a special socket for them? If so, what size?
Also, so I can torque them down to 100+ ft. lbs. when i lubricate the threads on the stud with engine oil? But not when I use the supplied lube? Can I use both?
As far as the torque specs, what is the optimum amount? Obviously, I don't want another BHG... So, the more torque, the better, right? What does everyone recommend?
More torque the better is wrong so very wrong....
I cut up a 7M head to check port wall thickness and they're quite weak in spots so if you over torque the studs you can deform the Head and it'll never seal.
Just go with ARP's supplied instructions and you'll be fine.
I cut up a 7M head to check port wall thickness and they're quite weak in spots so if you over torque the studs you can deform the Head and it'll never seal.
Just go with ARP's supplied instructions and you'll be fine.
lol yah im going to stick with the 85 since it seemed alot better to me and ill be usin molylube not arps moly but still moly.
Thanks guys ill probably post some pics in a few minutes of the build so far in my messy garage
Thanks guys ill probably post some pics in a few minutes of the build so far in my messy garage