Stumbled on this earlier. Looks like a decent testing methodology, and certainly gives interesting results.

 

Very interesting, thanks for sharing.

 

Those L19 studs are freakin serious man.

 

Thanks for sharing.

I almost bought a set of those Xotic head bolts they flashed at the end, but ended up just getting the Felpro stock replacements since it was just a stock-style rebuild. I was looking for something in between the ARP studs and the TTY bolts.

I may get a set of the Amazon studs next time, they actually seem to perform decent enough for the money.

 

Yeah, when I built.my motor I went with arp 8740 bolts. Wish I had known about the Amazon ones, for an N/A build they'd be great, even for higher horsepower builds.

 

So, would you rather have a bolt that stretches or one that breaks? What PSI is reached in a NA engine or a boosted engine?

 

Googling says that it can vary from 1500-300. I'm sure in a boosted application that could be much higher (hence why you'd want good studs for a high boost application). My guess is a high horsepower, super high compression motor (like something at 13:1 running e85) might push past 3k psi and maybe near 4k? I'm spitting numbers out of my *** though, I'm sure someone more knowledgeable can chime in.

As for stretching vs. breaking, I'd assume that you'd reach the point of plastic deformation long before the bolt/stud actually snapped. So unless your detonating the absolute ***** off the motor you'd lose compression long before you reached the point of bolt failure.

 

Is the clamping force determined by 1 bolt's rating or multiplied by the number of the bolts in the head?

 

I'm not an engineer, so take this with a grain of salt.

My assumption is that the further away from the source of your clamping load, the less clamping force is applied. Of course there are things that affect this (surface area of the clamp, amount of force exerted, etc etc), but that's why the bolts are spaced the way they are. In a perfect world I'd assume engineers would design things so that the distance between the bolts creates a perfect overlap where there is an even clamping force across the entire surface area. Since we don't live in a perfect world, I'd assume that there are some peaks and valleys in terms of clamping force across the head and deck, but that they are close enough that the head won't warp or lift in areas.

So to answer your question... the clamping force is multiplied in some areas and not in others?

 

Super good information!

Thanks for sharing

 

Videos like this are great, if you like videos like this check out project farm hes got hours of binge worthy videos doing tests on all kinds of things