Can You Reuse Torque To Yield?


Never reuse torque to yield (TTY) head bolts because, if you do it’s not unusual for them to break. If that happens you need to drill out what’s left of the bolt.

Can you reuse a torque to yield bolt?

Torque-to-yield (TTY) head bolts are designed to stretch when used. Once stretched, they are not as strong as before. Consequently, they cannot provide the same amount of clamping force and may break or shear off if reused.

How do you calculate torque to yield a bolt? (video)

https://www.youtube.com/watch?v=xFzTZG4eU70

What is the purpose of torque to yield bolts?

First, it overcomes friction between the threads in the block and the bolt as well as friction between the cylinder head the underside of the bolt head. Secondly, the torque stretches the fastener slightly to establish and maintain the desired clamp load on the gasket.

What happens if you over torque a torque-to-yield bolt? (video)

https://www.youtube.com/watch?v=bJ42_06DDrg

What happens if you reuse head bolts?

Bolts with any signs of damage, no matter how slight, should never be reused. Not only will the bolts eventually fail, but when they do, there is the potential for them to cause damage to your cylinder head. This results in a much more expensive repair than simply replacing the bolts in the first place.

Are Ford 4.6 head bolts torque-to-yield?

These ARP main studs have been installed in the 4.6L SOHC block, so this is not a torque-to-yield installation.

How do you use yield gauge torque? (video)

https://www.youtube.com/watch?v=tjGq2RzU9FU

Do you have to replace stretch bolts?

Can I Reuse Stretch Bolts? Stretch bolts also known as TTY bolts should be replaced each installation. TTY bolts have a maximum stretch capacity and they can be reused only when they have not met this limit.

Are head bolts torque to yield?

Torque-To-Yield Bolts

Used by many manufacturers, especially on engines with aluminum heads and in conjunction with Multi-Layer Steel (MLS) head gaskets, T-T-Y (Torque-To-Yield) head bolts are engineered to stretch within a controlled yield zone.

Are ARP bolts torque to yield?

No, ARP bolts are not torque to yield (TTY). TTY fasteners, when being torqued, actually stretch because of the elastic properties of the material. This gives them the needed clamping force, but the downside it that they aren’t reusable (well, at least they shouldn’t be reused).

Are flywheel bolts torque to yield?

All of the documentation that I found indicated the flywheel bolts are torque to yield, and not reusable.

How does a torque to yield bolt differ from a standard bolt?

With a standard bolt, a technician could torque the bolt to its yield point, and it would return to its original form and length when removed. It has elasticity; it can stretch and then return to its original form. This is not so with torque to yield bolts.

How much does a bolt stretch when torqued?

To appropriately answer this question, it helps to first consider that only approximately 10-15% of the input torque actually stretches the bolt; the remaining 85-90% of input torque is primarily used to overcome friction between the mating threads and friction under the bolt head or nut.

Should head bolts be oiled?

Do You Put Oil On Head Bolts? When installing head bolts, you should lightly oil them. The threads and heads should be lightly lubricated, but do not want to have the bores full of oil. The friction of the bolt head against the head surface will result in an inaccurate and insufficient torque when it is turned dry.

What will happen if you overtighten screws?

One of the most damaging ways to do that is by over-tightening, or over torquing the fastener. This can result in stripping screws, snapping screw heads and damaging pre-tapped threading.

What happens if you don’t torque to spec?

In the case of insufficient torque, it’s the stud or the bolt itself that suffers all the impact, causing it to shear. Alternatively, the engine’s vibrations can cause the bolt or nut to come undone, displacing the tensioner.

Can bolts be torqued more than once?

Mechanically, bolts may be reused provided the bolt never exceeded its yield point: a simple enough definition, but one that is more complicated than it may appear. This is because it is nearly impossible to verify if a bolt has ever been tensioned past the yield point.

Are head studs better than bolts?

In other words, head studs are better suited for high-performance vehicles with greater power requirements, while head bolts are more practical for personal, everyday automobiles. Therefore, it would be inaccurate to conclude that one type of fastener is categorically superior to the other.

Do head bolts need washers?

Yes, you need washers under the heads of the head bolts. Without the washers, the bolt’s head will cut into the aluminum causing uneven loading of the bolt torque.

How tight should cylinder head bolts be?

What Is The Torque For Cylinder Head Bolts? Torque between the bolt tips should range from 7-9 feet in height. One should tighten the bolt to 12-14 feet to eliminate the torque buildup.

Can you reuse 4.6 head bolts?

If a head bolt is rusted it should not be reused. A head bolt should not be reused if the threads are galled or badly damaged. Chasing damaged head bolt threads with a die will clean up the threads but also remove material (metal) and undermine the head bolt’s ability to torque down and hold to specs.

How much torque does a 5.4 Triton have?

500 lb-ft @ 3,750 rpm

Metric Value
Stroke 106 mm
Compression ratio 9.0:1 (2 valves) / 9.8:1 (3 valves)
Max power @ RPM 550 @ 6,500 rpm
Max torque @ RPM 500 lb-ft @ 3,750 rpm

How much horsepower does a 4.6 liter v8 have?

Ford 4.6L SOHC V-8

Ford
4.6L SOHC V-8
Horsepower (SAE net) 300 @ 5,750 rpm
Torque 320 lb.-ft. (434 Nm) @ 4,500 rpm
Specific output 65 hp/L

What is the formula to calculate torque?

A practical way to calculate the magnitude of the torque is to first determine the lever arm and then multiply it times the applied force. The lever arm is the perpendicular distance from the axis of rotation to the line of action of the force. and the magnitude of the torque is τ = N m.

How do you guess torque without a torque wrench? (video)

https://www.youtube.com/watch?v=gdfROk3-xCg

What does 90 degrees mean on a torque wrench?

90° = quarter turn. 180° = half turn. It’s alright if you are off a few degrees.

Is it safe to reuse stretch bolts?

However, because the tightening procedure does permanently stretch the bolt, there is some risk of breakage if the bolt is reused. And since there is no way to tell how many times a bolt has been reused, it doesn’t make any sense to reused TTY bolts – the risk far outweighs the replacement cost of used bolts.

Can I reuse cylinder head gasket?

You can re-use the Titan or Pro Copper style head gaskets several times, only if the head gaskets are cleaned carefully. If a buildup of sealant occurs, combustion pressure will not be contained as the Head/Gasket/Block will become separated by a layer of sealant which cannot withstand combustion pressure and heat.

How can you tell if a bolt is stretched? (video)

https://www.youtube.com/watch?v=_Uhul4DmWuw

How do you tell if a bolt has yielded?

Answer: Simply screw a nut on the previously used bolt’s thread to the head on a fully threaded bolt or to the thread runout on a bolt with a full diameter body. If a nut will not screw on the entire bolt thread length, the bolt has yielded and it is not safe to be reused.

Is torque angle necessary?

It is preferred that the fasteners are tightened using standard tightening tools. To avoid the need of any special tightening tools as servicing would be performed using standard equipment, torque-angle tightening method would meet most of the requirements.

What is the torque angle method?

The torque angle method is a more precise way of torquing a standard fastener to a predetermined tension. When using this method, the bolts are torqued to a minimal specification, say 20 foot-pounds and then tightened a further specified number of degrees, say 90 degrees.

Is it OK to reuse ARP head studs?

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.

Should you Retorque ARP head studs?

It they don’t specifically tell you to retorque the head fasteners then don’t. If you feel the need to retorque your head bolts or studs then follow the same pattern as you did when you initially torqued them down, do one at a time, and, especially with aluminum heads, we would advise doing it on a cool engine.

Do you put Loctite on head bolts?

NO! You can use blue locktite in alot of places, but your headbolts are not one of them. Headbolts need to be brought up to torque specs in stages, and in a specific order (see a motor manual), and then re-torqued after the engine has been run for awhile to make sure they are all at the proper torque value.

Can I reuse flywheel bolts?

The stock bolts stretch during installation so they’re not reusable – this set of bolts is not only reusable but actually costs about half as much as a new set of Toyota bolts.

Can I reuse Flexplate bolts?

You’re *supposed* to replace them, but myself and plenty of others have reused them several times. Just be sure to use red thread-locker and make sure the threads look good and make sure you have them torqued correctly.

How do you torque a flywheel?

Place a pry bar, pipe, or some other piece of metal between the bolt head and the ground. Turn the flywheel in the direction of engine rotation until it makes contact with your prop, and torque away!

Where are TTY bolts used?

Today, TTY fasteners are employed for bolted joints in a variety of automotive components, such as ball joints, knuckles and tie rods. Most of the applications are aluminum. However, TTY fasteners also are used on steel components, because they create a more consistent clamp load on the bolted joint.

Is a M8 bolt 8mm?

The defined diameter of metric bolts is actually slightly larger than the actual diameter of the bolt shaft. So an M8 bolt would have a shaft diameter that’s slightly under 8mm which means that the bolt should fit through an 8mm hole.

What is the purpose of a stretch bolt?

Stretch bolts are designed so that they can be elongated beyond their elastic limit into the plastic region without problems. When a specific tightening torque has been reached, the bolts are turned further through a defined angle, which pre-loads them into the plastic region.

Is a bolt stronger in shear or tension?

Bolted joints and also bolts are mainly designed to transfer loads from one part to another or for fixing them. they also designed for tolerating shear loads. therefore, it is obvious to be stronger in tension as its ductile behavior.

What is clamping force for bolts?

Preload is the tension created in a fastener when it is tightened. This tensile force in the boltcreates a compressive force in the bolted joint known as clamp force. For practical purposes, theclamp force in an unloaded bolted joint is assumed to be equal and opposite of the preload.


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