Header bolts - use lock washers?

[BruteForce]

After endless trial fits, I'm ready to torque up the header bolts. Should I use lock washers? Any gotchas I don't want to learn the hard way?

[bb71challenger]

From my meager experience I would say no. Just use quality header bolts. The hardened lock washers get "annealed" by the heat of the headers and actually start coming apart in my experience.

[BruteForce]

Glad I asked! I thought the answer would be "you moron, of course use lock washers!" I've also got some hi temp anti-sieze compound for the threads.

The bolts are the high strength ones from Tacoma Screw. They're expensive, but since I only need 12 the cost is trivial compared with trying to get out one that broke off!

[bb71challenger]

I am not an authority on headers so wait for confirmation before scrapping the lock washers. I have been wrong before   

[Topcat]

This should work where they won't loosen down the road. Haven't tried them yet.

http://www.summitracing.com/search/Brand/Stage-8-Locking-Fasteners/Product-Line/Stage-8-Locking-Header-Bolt-Kits/?autoview=sku

[Changin Gears]

What I have found with header bolts or nuts is that they don't actually loosen, the gasket compresses.  You have to go back and re-tighten them 2 or 3 times after temperature cycles.  Once you do this you're all set.

The dead-soft copper gaskets minimize this.

[73EStroker]

My TTIs came with flanged header bolts only. No washers. And yes they will lose their tension with the heat and cause all sorts of problems. As mentioned recheck them for tightness about a day after using them and a couple of weeks of running. Should be ok after that