ARP Heads Studs
01-03-2008, 09:21 PM
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Studs are MUCH more expensive then factory bolts. I used them in my build though, along with main studs. If you ever plan on running alot of boost or removing the heads it would be advantageous.
01-04-2008, 08:53 PM
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I was always taught that TTY bolts were used by the factory’s because they could get a more even clamping load across the head. I know that "studding the head" has always been a must for boost guys, but I wonder how well TTY style bolts would hold under pressure. I haven’t ever heard of any one lifting a head with TTY bolts. but I don't think anyone would run TTY after doing a "boost build engine"
01-05-2008, 11:19 AM
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Isn't parish still using the stock TTY bolts on his 600+rwhp 5.3 Fairmont? I think as long as the cyclinder pressures are kept reasonable, with ZERO detonation, I would think the TTY bolts would last. But once you start pushing coolant for any reason the TTY bolts are trash. The tensile strength on even the ARP standard bolts and studs is higher... which makes them superior over TTY bolts. But the bottom line is if you don't have a really good tune then head studs, even with 3/4" deck aftermarket heads, will not save you from blowing head gaskets.
Bill
Bill
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01-05-2008, 11:44 AM
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TTY bolts are designed to stretch a specific amount to maximize clamping force within their intended engineered limits... which leaves less room for error when applying forced induction to these motors. I am not sure I agree that TTY bolts offer a better clamping force. More even?... perhaps. IMO, tensile strength is where its at. But I certainly won't disagree with anyone that TTY bolts are plenty strong for what most guys are running. I am running 9psi (11 in the Winter 
) on my stock 5.3L... but I only run a maximum 14 degrees of timing and I also run Torco in my fuel.
Bill
) on my stock 5.3L... but I only run a maximum 14 degrees of timing and I also run Torco in my fuel.Bill
01-05-2008, 12:17 PM
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Commonly used for head bolts, main bearing caps and other areas requiring a high clamping strength in automotive engines. These bolts are not reusable. Torque to yield bolts are stretched past the elastic stage (where the bolt can return to original shape) to a yield point (stretched to deformity) creating the highest clamping force. This is just before the bolt breaks in two (shear stage). Torque to yield bolts allow fewer bolts to apply more clamping load than conventional bolts used in greater numbers. Torque to yield bolts can be identified by having a more narrow shank than a conventional bolt of the same size.
For those wanting more info on TTY bolts...
http://www.babcox.com/editorial/ar/ar20134.htm
Last edited by Wilde Racing; 01-05-2008 at 01:56 PM.
01-05-2008, 02:01 PM
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More info pulled.
I had pland on using TTY in my Boost built engine, the more I search the more I'm sure I'm going that route....
I had pland on using TTY in my Boost built engine, the more I search the more I'm sure I'm going that route....
Torque-to-Yield Bolts
One-time-use, or torque-to-yield (TTY), fasteners take advantage of the torque yield principle. Most torque specifications build in a 25 percent safety margin--they can be overtorqued by 25 percent before damage occurs. TTY bolts do not have this safety zone. They are designed to be tightened just into the yield point but not to the extent that the metal is distorted. The advantage is they deliver 100 percent of their intended strength, versus the 75 percent strength provided by regular bolts. The drawback is that they can only be used one time. Once they are removed from an application, they can no longer support the load they previously did, and they must be replaced with TTY bolts. Installing a conventional fastener in their place will result in a 25 percent weaker clamping force. Because TTY fasteners are used in a variety of applications, such as subframe mountings, it's important to identify these during the estimating process--not just for the additional cost involved but also to alert the technician.
One-time-use, or torque-to-yield (TTY), fasteners take advantage of the torque yield principle. Most torque specifications build in a 25 percent safety margin--they can be overtorqued by 25 percent before damage occurs. TTY bolts do not have this safety zone. They are designed to be tightened just into the yield point but not to the extent that the metal is distorted. The advantage is they deliver 100 percent of their intended strength, versus the 75 percent strength provided by regular bolts. The drawback is that they can only be used one time. Once they are removed from an application, they can no longer support the load they previously did, and they must be replaced with TTY bolts. Installing a conventional fastener in their place will result in a 25 percent weaker clamping force. Because TTY fasteners are used in a variety of applications, such as subframe mountings, it's important to identify these during the estimating process--not just for the additional cost involved but also to alert the technician.