Subject: RE: exhaust nut testimonial
Author: stephen brenton
Date: Jan 11, 2002, 11:48 AM
Post ID: 1709360535
I'll answer 2 issues in this post:
Thermal coefficients of expansion are such real small numbers (like
10E-6) and the temperature differences are relatively small numbers
(10E2) that the change in size of the nuts would be nearly impossible to
measure; I consider it to be negligable.
I put 8 holes (.045") in the nut for lockwire (leftover habit from IMSA
days). If you haven't seen the jpg, send me an email. Lockwire ought
to keep them from coming loose.
At the risk of starting a long debate (I hope not):
I have a little trouble with the double nut concept. You tighten the
nut on the exhaust, hopefully enough that the thing holds but not enough
to cause the weaker threads (the Alum head) to strip. Then you want to
take an external nut and tighten down on it adding further stress to the
threads. The external nut will act to add an additional 'pull' to the
exhaust nut and that load is added to the existing load that is already
on the Alum head. I know double nutting is widely used and common, but
I prefer lockwire.
stephen.
Bruce Giller wrote:
The SS exhaust for my Alfa came with SS bolts/nuts/lockwashers since the sections have bolt-together flanges. I've found that over time, the SS bolts have the tendency to disappear. I think it is from the vibration and the heat. To remedy the problem, I have double nutted them all. I wonder if the these SS exhaust nuts might do the same (meaning loosen up over time) especially if there is a lock nut on them. Bruce
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