Arp spec

[Twan]

I set all my studs at 235 ft lbs, when my injectors were installed, we checked them, they were all still at 235.
That means they didn't stretch right? Or can they stretch under load and return when cooled?

Thanks.

 

[Mdub707]

Every stud stretches. That's how they hold clamping force. Being set at 235 still just tells you the nut didn't loosen at all. I'm sure they're always stretching under load. As long as the pressure on the head exceeds the clamping force of the stud, they will stretch some miniscule amount. As long as they're not stretching enough to break the gasket seal and they're not stretched enough to yield the stud, you'll be fine. I'd say if it's not puking coolant and you're still at 235, you're in good shape.

You bring up another good point too, simply heating and cooling will change the size of the stud...

 

[Twan]

Thanks for the info.

I was pushing coolant. I decided to take them to 250, just to see. The truck isn't pushing coolant anymore. For now anyways. Lol.

When I had them at 235 it would push coolant at 28psi or higher, last night I was holding 29 psi pulling my trailer and the coolant psi was at 12 psi when I got home, use to be 16-20 psi.