Header Bolts

[jp2code]

Engines come with studs in the heads for mounting exhaust manifolds or headers.

A few years back, a mechanic was installing a set of headers on my truck. He removed the studs and used bolts in the heads instead because the area was too tight to get the headers over the studs.

Today, I am installing the SuperTrapp 2-1 exhaust on my old 2003 Sporty. While removing the exhaust, the old studs on the rear head snapped in two, so they need to be replaced.

In reviews of the SuperTrapp 2-1 exhaust, I noticed more than one person complaining about the 2-1 style being difficult to fit over the exhaust studs because the 2-1 is a welded piece that cannot be manipulated.

Is there any reason why I couldn't use bolts in the heads instead of studs?

Pros and Cons, please!

If I use bolts, what kind of bolts should I get? Stainless? Mild steel? Hardened steel?

[bustert]

studs are often used so the load or wear is not on the softer head material. also a lot of studs use diff threading on each end and also some have a limiter that prevents the stud from becoming too deep into the head material.
can you use bolts, why sure, just need to be more careful, also keep in mind, that studs have a "B" rating so keep the bolts close to that range. if not high enough, with repeated use and heat cycles, they can snap off, best to used new bolts every time.

[aswracing]

Originally Posted by jp2code

Today, I am installing the SuperTrapp 2-1 exhaust on my old 2003 Sporty. While removing the exhaust, the old studs on the rear head snapped in two, so they need to be replaced.

Don't be a fool and attempt to extract the broken stud with an easy-out. The situation will only go from bad to worse. That end of the stud, that screws into the head, is an interference fit thread. It's designed to bind up in the head, and it does a mighty fine job. People who don't know this often break off an easy out, thinking it can be extracted. At that point, the repair requires carbide or diamond tooling.

Bite the bullet and go get this tool. It's the right way to fix it. Generally speaking, it works so well that you drill right through the broken stud, leaving the shell of it which can be easily removed, and the threads remaining in the head are still intact. Worst case, you're heli-coiling it, but usually there's no need.

I would replace it with the factory stud, part number 16715-83, so that you maintain the interference fit thread. I have yet to see an aftermarket stud that has it.

If you want to use bolts, at the very least you should heli-coil or time sert each hole. Otherwise the bolt will just tear up the aluminum over time. To the extent the exhaust moves around relative to the motor, it's flexing those fasteners.

I've installed lots and lots of exhaust systems, both 2:1's and 2:2's. The only one I've ever encountered that was difficult to mate to the heads was the V&H Short Shots, which ironically, are a 2:2 design, albeit with the two pipes welded to each other. Perceived difficulty in installation is not a good reason to compromise the attachment of the pipes to the heads, in my opinion. To each his own.

[denguy]

If you use bolts, put some high temp rtv sealant on them, might keep them from vibrating loose and you can still get them back out without thread damage.

[bustert]

super duper +1 mr. aswracing.

even applies to engine mfg decades ago!

[Toejam503]

Oval the holes on the header pipe, just a little, to get them to slide on. Studs are more reliable as the torque rating is only around 9ft.lbs.