96'BlueGT

So i recently installed PI heads with new bolts and they came with the wrong cam caps since they where bought from a 3rd party. I want to just put my old heads back on and trash the PI heads.

I have only ran the engine a max of about 30mins total, can i re-use the head bolts since they where brand new when i bought them? or are they trashed the instance you torque them in the sequence?

09GT/CS

Depends on what you have pretty sure the stock style are torque to yield but if it was only idling for a short time you may get away with it but no guarantees. If they are an aftermarket brand is call them directly and ask. I know it may cost more money but is it really worth it to skimp and risk leaks/ damage because it won't hold correct/ even pressure?

96'BlueGT

The kit was TTY bolts, does that mean when they get torqued they are there until they bust or change heads with new bolts ?

09GT/CS

Yeah it means once torqued they stretch slightly. After that torquing to the same spec will not yield the same clamping force on the head since they are now slightly longer. Some people get away with it some don't. It all depends on your mating surfaces and gasket thickness and so on. Really no way to know for sure until you try it unfortunately.

oxfordgt

This is not true. TTY bolts can be reused many times as long as you are the one that torqued them to the correct specs. Every bolt out there stretch when properly torqued that is how they are designed. TTY bolts are just a very strong bolt that clamps more than other bolts including ARP but only if properly torqued. Over torqued and they are ruined which is why you can only reuse them if you torque them in the first place.

jwog666

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. This is because of its elasticity, it is able to stretch and then return to its original form.

This is not so with torque to yield bolts. There are two terms related to this phenomenon. The first is elastic deformation and the second is plastic deformation:

Torque to yield bolts.
1. Elastic deformation: This is the amount of force or torque where the bolt hasn't changed shape or length. At this point the bolt is reusable because it hasn't changed its shape.

2. Plastic deformation: This is the point past elastic deformation where the bolt has changed its shape and length. At this point the bolt cannot be reused and needs to be replaced.

For example, an aluminum cylinder head could be torqued in a sequence of one to ten. On the first pass, the head bolts are torqued to 36 foot pounds. This is the elastic deformation point. The second pass would be a 90 degree angle or a quarter turn. At this point the bolt is going into plastic deformation. The third pass would be another 90 degree angle. At this point the bolt has changed its form, and if loosened or removed, it must be replaced with a new torque to yield bolt.

^^^^^^ the reason they shouldnt be re used, but hey, what do engineers know?

Granatelli Sales

TTY bolts should only be used one time and disposed of when removed.

We are a dealer for ARP, if there is any hardware you need, we can get it for you.

school boy

I have heard ppl reuse them, but as cheap as they are buy new.