Because of this, many standard head bolts are okay to use more than once, as long as they have not been stretched past their spring back point. Once this occurs, they should no longer be used in the engine, as they won’t clamp properly.
Can stretch bolts be reused?
stretch to ensure proper securing when tightened down. (Bolts with Specification: Torque plus Angle). Some of these bolts can be reused, if you torque them to the same torque that you would use for a normal bolt of the same size, pitch, lubrication factor, and strength rating.
Can torque to stretch fasteners be reused?
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.
Is it OK to reuse head bolts?
Can I reuse head bolts? … 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.
What happens when you 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.
Should head bolts be oiled?
As a rule, the threads and underside of the head on most standard automotive head bolts should be lubricated with motor oil before the bolts are installed. The torque values specified by the engine manufacturer are typically based on oiled threads and fasteners – not dry fasteners.
Can you reuse a bolt with Loctite?
Contrary to common belief, any bolt that has been locked with threadlocking adhesive may be reused by removing old adhesive before applying new and reassembling. … The strength and viscosity of the adhesive needed for an application are directly related to the size of the fastener used.
How many times can you use head bolts?
Stretched Head Bolts
Bolts are designed to stretch as you torque them into place, and when you remove them, they snap back to their original position. Because of this, many standard head bolts are okay to use more than once, as long as they have not been stretched past their spring back point.
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.
How do you reuse head bolts?
Tips for Reusing Head Bolts
- Clean and Inspect. Because of the intense heat that the head is in, the bolts will occasionally fail when torque is applied to remove them. …
- Soak in Oil. After you have determined the bolts are still usable, soak them in motor oil for at least 24 hours. …
- Clean Thread Holes. …
- Use Torque Wrench.
Can you over torque a bolt?
Yes, you can over-tighten a bolt, but doing so is unlikely. Most bolts come with instructions that the bolt’s maximum torque. The ó-inch Power Bolt, for example, has a maximum torque of 25-foot pounds.
Can you reuse Grade 8 bolts?
RE: Reusing Grade 8 Bolts
As long as your fastener is kept within its elastic range, in most applications you should be fine reusing fasteners. If its a torque to yield application, then certainly reuse of the bolts would be a bad idea.
Do bolts stretch when torqued?
A torque to yield fastener (TTY) or stretch bolt is a fastener which is torqued beyond the state of elasticity and therefore undergoes plastic deformation, causing it to become permanently elongated.