How many have lifted a head with TTY bolts?
01-06-2008, 08:41 PM
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How many have lifted a head with TTY bolts? I've tried to do a search, but there is WAY to many posted about tty bolts. I know studs are stronger. But I'm curios to see how many people actually have lifted a head using TTY bolts? Please post some info about the engine as well..
01-06-2008, 09:59 PM
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I haven't heard of any instances. I would think that TTY bolts are plenty strong for 99% of all motor combo's out there. I would also say that ARP head bolts are just to cheap and easy to install to not use them. Hell, they are reuseable, AND they have a higher tensile strength.
It's like swapping a motor and not changing mounts you know?
It this question geared towards a problem with your very sick truck??
E
It's like swapping a motor and not changing mounts you know?
It this question geared towards a problem with your very sick truck??
E
01-06-2008, 10:17 PM
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I haven't heard of any instances. I would think that TTY bolts are plenty strong for 99% of all motor combo's out there. I would also say that ARP head bolts are just to cheap and easy to install to not use them. Hell, they are reuseable, AND they have a higher tensile strength.
It's like swapping a motor and not changing mounts you know?
It this question geared towards a problem with your very sick truck??
E
It's like swapping a motor and not changing mounts you know?
It this question geared towards a problem with your very sick truck??
E
I understand that ARP has a High tinsel strength, but if a TTY bolt is stretched to near fracture, will it be less likely to stretch and allow gasket failure over a stronger less stretch bolt/stud?
I'm not trying to save a buck on my engine, I just thing there may be a better option even if it is out of the norm.
Last edited by Wilde Racing; 01-08-2008 at 10:12 PM.
01-07-2008, 12:56 AM
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tty based on what i have learned in college as a engineer tty would be using the maximum strenght of the steel and it would not be able to stretch any further therefore it technically should not allow the heads to lift. the only reason i would use arp studs is because they are reusable and easier to remove and replace the heads.
(Beaflagvonrathburg)"How do you plan on stretching them to near fracture?"
The steel is stretched to its yield stress or the point where the steel is no longer elastic and just before it breaks. this is done by torquing the bolt to a high specification then the bolt is lossened and torqued again to the proper specification which is lower than the first. this enables the steel to stretch then it is torqued after it is stretched.
(Beaflagvonrathburg)"How do you plan on stretching them to near fracture?"
The steel is stretched to its yield stress or the point where the steel is no longer elastic and just before it breaks. this is done by torquing the bolt to a high specification then the bolt is lossened and torqued again to the proper specification which is lower than the first. this enables the steel to stretch then it is torqued after it is stretched.
01-07-2008, 01:32 AM
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I don't think ARP's are TTY. I know the studs are not, but I'm not sure about the bolts. I guess if the bolts are TTY and are rated at a higher tensil strength, they would be the best choice for max clamping force.
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01-07-2008, 01:51 AM
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I'm guessing here but I think the TTY bolts are just GM's way of cutting manufacturing costs. It is a lot easier and cheaper to maintain calibration on a stepper motor that turns a wrench so many degrees than on a strain gauge that has to accurately measure x amount of torque.
01-07-2008, 08:58 AM
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I'm guessing here but I think the TTY bolts are just GM's way of cutting manufacturing costs. It is a lot easier and cheaper to maintain calibration on a stepper motor that turns a wrench so many degrees than on a strain gauge that has to accurately measure x amount of torque.
01-07-2008, 01:21 PM
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TTY bolts allow for a one time use that provides a higher clamping force between the bolt head and the part. The bolt is taken beyond the 2% elasticity range and into the plastic deformation range. Thats why they must be replaced after one use. The second and subsequent times the bolt will recess even further into the plastic deformation range and the extra desired clamping force will no longer be there as the bolt becomes weaker. Its a one time deal only. Its not unlike strain hardening or work hardening.
01-07-2008, 02:09 PM
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ALL fastners stretch including GM TTY, ARP studs, and ARP bolts.
ARP uses a high tensil strength steel.
The NHRA nitro guys use ARP studs becasue they are strong; they develop 6,000 HP in a 500 cube inch engine so their dealing with extreme pressures.
I bought a few brake caliper bolts from a metric bolt and fastener supply house Friday. I asked the engineer to explain TTY bolts. He said the heads are a tad different but you could not tell the difference if you had two broken bolts (a TTY and a non-TTY-non-ARP bolt) under a microscope.
Somehow, this gives me pause to think. Several years ago, I bought some GM TTY head bolts from a local GM dealer. He laughed at me and said the dealership has been doing warranty work for years and has never used new TTY bolts. They re-use the old TTY bolts with no issues.
I don't advise re-using old TTY bolts becasue of the labor involved and realitive low cost of a few new bolts but, apparently, some have tried this without adverse effects.
If I ever rip my heads off again, I will be going with ARP - probably studs.
ARP uses a high tensil strength steel.
The NHRA nitro guys use ARP studs becasue they are strong; they develop 6,000 HP in a 500 cube inch engine so their dealing with extreme pressures.
I bought a few brake caliper bolts from a metric bolt and fastener supply house Friday. I asked the engineer to explain TTY bolts. He said the heads are a tad different but you could not tell the difference if you had two broken bolts (a TTY and a non-TTY-non-ARP bolt) under a microscope.
Somehow, this gives me pause to think. Several years ago, I bought some GM TTY head bolts from a local GM dealer. He laughed at me and said the dealership has been doing warranty work for years and has never used new TTY bolts. They re-use the old TTY bolts with no issues.
I don't advise re-using old TTY bolts becasue of the labor involved and realitive low cost of a few new bolts but, apparently, some have tried this without adverse effects.
If I ever rip my heads off again, I will be going with ARP - probably studs.
01-07-2008, 02:24 PM
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...the interesting part here is the aluminum blocks.
I would think the threads in a soft metal like aluminum would give up before GM TTY bolts or ARP fasteners would break.
You might want to post this question on the forced induction forum since they may have more experience with these issues.
What ever you decide, take extreme care in cleaning the block threads well before using any fastner. This applies to new and used engine blocks.
I would think the threads in a soft metal like aluminum would give up before GM TTY bolts or ARP fasteners would break.
You might want to post this question on the forced induction forum since they may have more experience with these issues.
What ever you decide, take extreme care in cleaning the block threads well before using any fastner. This applies to new and used engine blocks.
01-07-2008, 02:31 PM
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I understand that all bolts stetch. My question is are studs really a better choice? Tty bolts offer more clamping force and a more even torque across the head. But would a tty bolt be more likely to stetch under load even if its tensile strength is lower?
01-07-2008, 03:06 PM
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I'm not qualified to answer that question but only note that the NHRA nitro guys use ARP studs, presumably, for a very good reason. They still have catistrophic engine failures on a routine basis but I don't see any NHRA fuel teams using TTY bolts.
I would have to assume from this fact that the ARP stud is a better choice for extreme engine applications.
....see what the forced induction guys think....
I would have to assume from this fact that the ARP stud is a better choice for extreme engine applications.
....see what the forced induction guys think....
01-07-2008, 05:25 PM
#15
The steel is stretched to its yield stress or the point where the steel is no longer elastic and just before it breaks. this is done by torquing the bolt to a high specification then the bolt is lossened and torqued again to the proper specification which is lower than the first. this enables the steel to stretch then it is torqued after it is stretched.
01-08-2008, 10:20 AM
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I feel studs are a bit overkill on a street machine and really make things difficult/impossible if you are working on the engine in the car. I will most likely be using ARP bolts on my heads. FWIW straight from ARP's catalog:
HEAD STUDS vs. BOLTS...
A TECHNICAL DISCUSSION
ARP’s factory Tech Representatives are often asked which
is better, cylinder head studs or bolts. The answer, invariably,
depends on the installation. On many street-driven vehicles,
where 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.
And for good reason. 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. Here’s why. When you use bolts to secure the head,
the fastener is actually being “twisted” while it’s being torqued
to the proper reading. Accordingly, the bolt is reacting to two
different forces simultaneously. A stud should be installed in
a “relaxed” mode – never crank it in tightly using a jammed
nut.
If everything is right, the stud should be installed finger
tight. Then, when applying torque to the nut, the stud will
stretch only on the vertical axis. Remember, 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 and bolts are re-torqued after the engine has
been run.
A TECHNICAL DISCUSSION
ARP’s factory Tech Representatives are often asked which
is better, cylinder head studs or bolts. The answer, invariably,
depends on the installation. On many street-driven vehicles,
where 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.
And for good reason. 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. Here’s why. When you use bolts to secure the head,
the fastener is actually being “twisted” while it’s being torqued
to the proper reading. Accordingly, the bolt is reacting to two
different forces simultaneously. A stud should be installed in
a “relaxed” mode – never crank it in tightly using a jammed
nut.
If everything is right, the stud should be installed finger
tight. Then, when applying torque to the nut, the stud will
stretch only on the vertical axis. Remember, 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 and bolts are re-torqued after the engine has
been run.
01-08-2008, 10:46 AM
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One other thought; see the ARP web site that discusses fasteners.
http://www.arp-bolts.com/index.html
http://www.arp-bolts.com/index.html
02-06-2008, 12:28 PM
#18
The original post was regarding which bolts for FI, where the higher pressure may eventually start lifting the heads off the block requiring ARP studs or bolts.
Wouldn't it be safe enough on a stock-cubed NA LS1 to go with the GM TTY bolts? It seems to me like the bolts (and studs especially) are a bit overkill for a mild application?
Wouldn't it be safe enough on a stock-cubed NA LS1 to go with the GM TTY bolts? It seems to me like the bolts (and studs especially) are a bit overkill for a mild application?
02-06-2008, 12:56 PM
#19
the chances of lifting a stock head with TTY bolts are negligible at best, even with reused stockers (though its still probably not a really good idea). NHRA race teams use studs because the engines must be disassembled and reassembled quickly and, in some cases, after every single race, making bolts impractical. when a TTY bolt stretchs to its maximum limit, it is correct to say that the bolt cannot stretch any further; however, if sufficient stress is applied to the bolt it will fail. Conversely, a high tensile strength stud, due its higher strength, has a realatively low ductility (stretchability, if you will) in relation to a TTY bolt. It would seem to me that a properly torqued ARP stud would fail long after a porperly torqued TTY bolt because the TTY bolt has already been pre-stressed.
