Date: Tue, 6 Jul 2004 12:29:04 -0700
From: "Jay Mackro" <jmackro@domain.elided>
Subject: [alfa] Stainless fasteners in exhaust systems
Dean Cains had suggested:
> If you want a trick to make the exhaust installation a bit easier, buy a
> set of stainless steel nuts, bolts, and washers for the connection between
> the manifolds and the downpipes. Weld .....
I had tried something a bit simpler, and had some strange results.
My '76 spider has a catalytic converter attached to the exhaust
pipes with two, three-bolt flanges. I figured "hey, SS is the way
to go", and bought some 5/16" X approx. 2-1/2" stainless bolts,
nuts, and lockwashers. I needed to remove the cat a couple of
months later, and tried to loosen the six bolts. Two of them were
locked up - totally frozen. The bolts fractured before the nuts
would loosen. No they didn't look corroded, and no, I hadn't
used Loctite or anything else on the threads.
My question for all you metallurgists out there is: Does stainless
steel tend to "gall" or otherwise lock up, especially when exposed
to heat? Should I have used oil, anit-seize, or some other lubricant
on the threads (of course, would that have survived the heat of the
exhaust system?). I replaced the SS nuts with regular steel ones,
but retained the SS bolts. My hope is that this combination will give
the desired result.
Jay Mackro, San Juan Capistrano, Ca.