Not necessary, I have done about 25 local cam swaps and have reused the stock bolt several times and have never had one come loose.

 

Just because you do something wrong and get away with it doesn't make it the right thing to do.
It is a torque to yeild bolt. That means that when it's properly torqued it's stretched. When you loosen it up it doesn't spring back. If you use it again and torque it properly again there is no more stretch and it will not have the proper clamping force.
It's a $3-4 dollar item. There's way better places to corners like skipping your next Big Mac.

 

BLASPHEMY!!!!!!

 

So torque it up a few more pounds!



[/backyard mechanic]

 

Did I say it was the right thing to do? Show me one thread on here that someone reused the stock bolt and had problems. It will not hurt anything. Do you buy new gaskets when you do a cam install also?????

 

I just explained it. Torque to yeild means, stretched to the point of almost destroying it, that the bolt can only be properly torqued once. If used again it can, not will, fail.
If you're to thick to understand it then oh well. For the price of that bolt it not worth taking a chance on the bolt coming loose.
I suppose that you'd reuse the stock head bolts too?

Reusing a gasket you take a chance of a leak and yes I inspect the gasket for damage and reuse it if it's not hurt.

 

It's got to do with metallurgy Pete. Steel has some elasticity. Regular torque values tighten a bolt until it stretches, causing the clamping force to hold the 2 parts together, within it's ability to return to normal shape and size when unbolted. Torque to yeild bolts go just beyond that, just to the point of no return. If used again they can permanently stretch which lessens the clamping force.