On Thu, 10 Apr 2008 04:16:25 -0400, "Roger Long"
wrote:

"Lew Hodgett" wrote

BTW, replace the copper washers on any fuel banjo fittings you break open.

This is a point I've wondered about. Before becoming the owner of a boat
diesel, I'd always heard that copper washers are never reused. The Banjo
fittings are part of the fuel bleed points on me engine so have been cracked
open many times and I put all the old washers back. Everything seemed tight
against fuel pump pressure of approximately 7 psi.

This is all upstream of the injection pump however. Downstream, I expect it
to be a different story with the much higher pressures. More info from and
details of annealing appreciated.

Theoretically the soft copper washer deforms as the fitting is
tightened to form a seal. In the practical world it doesn't seem to
matter much. As long as they are there they usually seal. The biggest
problem I have had is dropping the little things in the bilge. If you
have your injection pump calibrated or the injectors rebuilt at the
local injector repair shop and you talk nice you can get a handful of
copper washers. Then you have a stock of spares and can scatter them
through the bilge like sewing wheat.

The one place that I have seen a solid copper seals leak was a Royal
Enfield motorcycle that I had in collage. It used a solid copper ring
as a head gasket and if you didn't properly anneal that ring the head
was guaranteed to leak. I've also always been suspicious of injector
seals and have always tried to use a new washer there although I have
annealed some and reused them and had no problems.

I really hate the Japanese Banjo fittings and on my present boat have
re tapped all the holes and converted to AN fittings.

Bruce-in-Bangkok
(correct email address for reply)