What is recommend to use on the threads of exhaust manifold bolts or studs?
If you are reusing exhaust manifold bolts (which we don’t recommend), apply a metal fortified anti-seize to your manifold bolts. If you’ve just removed the broken bolts and ready to complete the repair, chase the threads clean and use fresh OEM bolts for best results.
Do you need special bolts for exhaust manifold?
Are exhaust bolts special? Exhausts are not high stress areas so the bolts can be 8.8 or even softer. We used to use brass nuts on exhaust manifolds so the nut could be easily cut off in the unlikely event it seized. Grade 4.6, 4.8 or 5.8 should be all be fine.
What grade are exhaust manifold bolts?
Common practice is to replace the exhaust manifold bolts on ’94 – ’96 cars with Grade 8 hardware. They are hardened and will carry the highest tensile load, which seems to help them withstand the heat cycles the bolts are exposed to.
Do you use anti seize on header bolts?
Anti seize is a good idea on header bolts in general, in my experience. Even steel in steel they tend to freeze up over time (if they don’t fall out, as they did to you). The advice to use some type of lock is also a good one.
Can I use bolts instead of studs?
For a performance or heavy-duty application, the use of studs is preferred whenever possible instead of main cap bolts, in those instances where a choice is available. Studs provide the ability to obtain much more accurate torque values because the studs don’t twist during tightening as do bolts.
Can you use regular bolts on exhaust?
Fine if you want to do it, but not necessary. I’ve had to replace just enough exhaust manifold studs because of galling to exclusively use brass nuts there too. When I first used them I was paranoid about them not doing the job. That’s not a worry anymore and hasn’t been for more than a decade.
Do I need special bolts for headers?
For secure fitment, header bolts need maximum thread engagement, without bottoming out in the cylinder head. Most headers with 1/4-inch or 5/16-inch thick flanges will use bolts with a 3/4-inch UHL, while 3/8-inch thick flanges normally require bolts with a 1-inch UHL.
Can I use regular bolts for headers?
Why are studs stronger than bolts?
Because the stud is torqued from a relaxed state, the pressure from the nut will make it stretch only along the vertical axis without a concurrent twisting load. The result is a more evenly distributed and accurate torque load compared to that of the head bolt.