torque to yield harmonic balancer LS1

[Injectedcutty]

You will never get close on a stand so wait until it's mounted in the frame. It's a bear for sure. I think I Used a 4 foot piece of 1" heavy wall pipe as a cheater on a half inch breaker bar and it was still tough

My dad and I did mine the 1st time with it on the engine stand and ARP bolt. It was nuts and we almost flipped the dang thang over lol!!! Last year when I had to pull the pulley to change the timing cover seal, I just ran the bolt on with 1/2" ugga dugga maker until it stopped.

 

[pontiac guy]

If you took that bolt off another engine it's garbage. Yes you may get away with reusing it, but yield means the bolt has been stretched beyond it's elastic limit. As in permanently deformed, stretched failed. Buy a new one. That's why people always replace them with ARP bolts.

Torque to yield bolts are 1 and done fasteners.

 

[Northernregal]

If you took that bolt off another engine it's garbage. Yes you may get away with reusing it, but yield means the bolt has been stretched beyond it's elastic limit. As in permanently deformed, stretched failed. Buy a new one. That's why people always replace them with ARP bolts.

Torque to yield bolts are 1 and done fasteners.

Disagree. tensile strength testing shows single use TTY headbolts are stronger than new.

For an NA build I would reuse all TTY bolts in the motor.
10psi boost, still reuse TTY.
Above that, ARP studs.

I will never replace the crank bolt. I would love to see data on stretch of a 16mm fastener, please prove me wrong.

 

[64nailhead]

If you took that bolt off another engine it's garbage. Yes you may get away with reusing it, but yield means the bolt has been stretched beyond it's elastic limit. As in permanently deformed, stretched failed. Buy a new one. That's why people always replace them with ARP bolts.

Torque to yield bolts are 1 and done fasteners.

This ^^^ is the official answer - and you'll never have a failure if you follow this. But............


it's been found, by 4 out of 5 dentists surveyed, that you can reuse an LS balancer bolt and head bolts with no detrimental results. Like I mentioned in my last post, all comes down to a Beatle's song - All You Need Is Love - I don't love the $250 I dropped on mine, but I understand why the OP loves his.

To each his own.

 

[64nailhead]

I will never replace the crank bolt. I would love to see data on stretch of a 16mm fastener, please prove me wrong.

I agree on the crank bolt - I measured 3 against a new - you're talking they are all within .002" the same and the stretchy area is inside of a .0005". Proof's in the puddin' mate - it's been done to 1000+HP at 8000rpm's.

 

[Texas82GP]

I agree on the crank bolt - I measured 3 against a new - you're talking they are all within .002" the same and the stretchy area is inside of a .0005". Proof's in the puddin' mate - it's been done to 1000+HP at 8000rpm's.

Don't hurt precious.

 

[black_aerocoupe]

excellent advice. I will use lumber to stabilize the stand.

These bolts are one time use supposedly... I thought that meant they were yielding.

When a service manual or guide refers to bolt as one-time use, it could mean a few things. Some bolts from an OEM parts source have thread locking compound, sealant, or lubricant pre-applied. So instead of specifying a specific sealant / lubricant / compound, they just tell their techs to use a new bolt. This stands to save time, and they make more money on more parts going through their parts business. There are some factory service manuals showing fasteners being able to be re-used with something applied to the threads, and the same application "requiring" new fasteners to replace the old. Really, it's no different than any part assembly. I've replaced voltage regulators before. But anymore, I replace the alternator.

True torque to yield bolts like stated by someone above, refers to the bolt being stretched to an extent they are not designed to reliably be used again. The stretch process is only able to work when the shank of the bolt is equal to, or smaller than the smallest part of the threaded section.

A TTY bolt materialistically isn't anything different from any other bolt of a similar grade, you just tighten it past the typical elastic region and into the plastic region where it stretches permanently unlike a normal bolt where you torque it to a point where it stretches temporarily.

You can buy a grade 5 hardware bolt and torque to yield it in the same way as a ARP bolt, it just takes a different level of torque.

A bolt torqued using TTY is yielding but it depends how far up the stress curve you get before you start necking the shank diameter down and reduce strength due or just flat out exceed the ultimate tensile strength of the material.

It sounds like you're confusing torque-to-yield bolts with torqueing processes, such as those which use a degree of turn. Different things. You won't commonly see any hardware store bolt that is able to be considered a torque-to-yield bolt. A bolt that is stretched specifically is going to fail at the threads before stretching a shank that is larger than the minor diameter of the threads.

 

[doood]

When a service manual or guide refers to bolt as one-time use, it could mean a few things. Some bolts from an OEM parts source have thread locking compound, sealant, or lubricant pre-applied. So instead of specifying a specific sealant / lubricant / compound, they just tell their techs to use a new bolt. This stands to save time, and they make more money on more parts going through their parts business. There are some factory service manuals showing fasteners being able to be re-used with something applied to the threads, and the same application "requiring" new fasteners to replace the old. Really, it's no different than any part assembly. I've replaced voltage regulators before. But anymore, I replace the alternator.

True torque to yield bolts like stated by someone above, refers to the bolt being stretched to an extent they are not designed to reliably be used again. The stretch process is only able to work when the shank of the bolt is equal to, or smaller than the smallest part of the threaded section.


It sounds like you're confusing torque-to-yield bolts with torqueing processes, such as those which use a degree of turn. Different things. You won't commonly see any hardware store bolt that is able to be considered a torque-to-yield bolt. A bolt that is stretched specifically is going to fail at the threads before stretching a shank that is larger than the minor diameter of the threads.

Thanks man.

 

[Hoopty_Mike]

Me after 3 LS swaps all cammed finding out the crank bolt is TTY:

 

[64nailhead]

Me after 3 LS swaps all cammed finding out the crank bolt is TTY:

View attachment 172912

The look I have after twisting off a left hand thread bolt not knowing it was left hand thread.