[Healeys] Possibly Helpful Tip

[Bob Spidell]

I've gotten so many helpful replies to my requests today I thought I'd 
pass along an observation I made before my last road trip.

I've had trouble getting a good, persistent seal on my exhaust 
manifold-to-downpipe flanges.  The flanges are flat, and I've tried both 
the copper- and steel-faced gaskets; neither lasts for long.  The brass 
stud nuts keep loosening, and I've gotten into the habit of tightening 
them frequently.  When going through the car prior to the trip, I was 
tightening the nuts (again), and one of them stripped (moment of panic: 
is it the nut, or the stud that's stripped???!!!).  Anyway, I replaced 
the nut with one of the many spares I keep and headed out on the trip 
(3,600 miles in 9 days).  Most days, I would lay on my back and tighten 
the nuts with a ratchet, two extensions and a deep socket before 
starting the day's driving.

What I noticed: the nut that was replaced stayed tight, while the other 
5 were always various degrees of loose at the start of the day.   I 
surmised that the threads on the soft brass nuts either erode or 
distort, making it impossible to keep good torque/stretch on the studs.  
It could be that brass nuts should not be re-used--the 
new-when-installed, never tightened brass nuts on my head-to-exhaust 
manifold studs have been fine for many miles--but I've never heard that 
anywhere.

My recommendation is to not re-use brass nuts on exhaust studs, they 
aren't cheap nor are they particularly expensive, but they don't seem to 
be reusable.  Alternatively, you could use steel nuts with anti-seize, 
but I don't know if this is a good idea (anyone?).


bs

-- 
*******************************************************************
Bob Spidell           San Jose, CA            bspidell at comcast.net
*******************************************************************