Date: Tue, 07 Sep 2004 14:06:36 GMT From: amesnospamrak.demon.co.uk (Andrew Stephenson) Subject: Re: Oil plug gasket..
In article <pq9rj0h2uvgnpfm0qhjkt2oojp3cj5qiv1nospamcom> nopenospamlmakingupaddresses.com "Bob" writes: > SO you're saying that the copper gets hardened through the > heating and cooling cycles of the engine running? I've always > wondered about these things... I thought we changed them due to > scratching during tightening. But, I was just guessing. Just in case this doesn't get said... Vibration and generalised "working" (ie, mechanical flexing) of the copper will harden it. Some of this will come from temperature cycling; but don't forget how much vibration happens during everyday operation. Work-hardening, I was once told, is why chains used for carrying loads should be annealed (put through a softening heat treatment) at intervals, to stop them getting too brittle. -- Andrew Stephenson