bcmaxx said:
on a differnt note: I went here:
http://www.geocities.com/JeepI6Power/screws.html
to get the head stud and nut size, it states either brass or bronze hardware why? Do you threadlock them in? Jeep wants $36 bucks perstud (idiots,everything I price I end up getting at the jobber) also what to torque these too?
Copper-based alloys won't seize against iron like steel will. Also, copper-based alloys will get incrementally
stronger when heat-soaked and allowed to cool, vice getting incrementally weaker (like steels. Steel can be annealed at temperatures as low a 500*F.)
I use silicon bronze for manifold hardware, and I'll use brass nuts everywhere else. If you do have to use steel hardware, use SAE Grade 5, as it's a bit less sensitive to heat-cycles and annealing (due to not being heat-treated as extensively.)
I have verified this experimentally - using heat-treatment ovens and test instruments available at school.
The same torque value may be used for brass or bronze as for steel - 19-21 pound-feet. I would suggest you go closer to 19 pound-feet and turn the screws slowly, as brass or bronze isn't as hard as mild steel (although quality silicon bronze can come close.) I've also found that a thin coat of RTV Copper on both sides of the manifold gasket doesn't go awry, and can help things all around. If you want to treat the threads, use LocTite #272 (or equivalent) or
nothing. You don't really need "never-seez" on those threads, and they can work loose without help. Lubricating the threads can be counter-productive.
The studs aren't strictly necessary - they're a convenience. They give you something to hang the manifolds on while you start screws. You can cut them from brass or steel threaded rod (most steel threaded rod is HT to SAE3 or SAE5 anyhow) and get rod threaded 3/8"-16. Yes, the OEM studs have a coarse pitch on one end and a fine pitch on the other - there is a sound reason for doing so, but it doesn't really apply here. Making studs with all one thread will work just fine (I've done it a few times.) You'll only need two or three - both ends, and I've sometimes seen a stud in the centre top hole as well.