Permatex Copper Spray-A-Gasket Question and a Head Torque Question

[jonyyuma]

It's the stretch of the fastener that maintains the clamping load, so each time the bolt is cylced it loses strength. On chevy head bolts for example, you cannot even attain the torque spec if you try to reuse them once. They just keep stretching until they fail.

Exactly, some of them by different mfrs. will say to measure length, others say check diameter. Newest say replace each time..My old tractor head bolts weren't marked at all or had rusted off the tops?

 

[Car Doc]

Stretch to yield bolts is now days technology to allow aluminum heads and cast iron blocks co-exist and its a very very poor way to go about it. (super slick surfaces and MLS gaskets and std bolts is the new way) I deal with them all the time they pure suck imho.

His old tractor wouldn't have anything like that if they would torque to spec and everything is level they will work simple as that.

edit; Most head bolts/studs are hard bolts (except the torque to yield crap) never saw a grade 5 etc all 8's or better.

 

[mudyshoe]

Hi, I used Copper vote on my case vai head when I rolled it over, it worked just fine, no leaks, got all spects off of a site called tractor data. The gasket was steel.