The
carb overflow tubes route excess gas away from the
hottest portion of the exhaust manifold. If the floats
or float valves malfunction or fuel pressure is too
high; the gas has to go somewhere. When an engine
design has the exhaust and intake on the same side of
the engine it is critical that the fuel dump be away
from at least the upper portion of the exhaust
manifold or headers. The original tubes routed it down
the side of the engine. I have purchased cars and
repaired cars for people that have had engine fires;
it is not an economical situation; even if the fire is
stopped before it takes anything other than the carbs,
wiring and master cylinders.
Above
are some carb overflow tubes. The one in the middle;
#160-92 is the original 1500 1600 tube; used on both
the front and rear carbs. These are no longer
available. The other two are from another Datsun that
had SU carbs. The bends are in different spots;and the
angles are different; and overall path is different
front and rear. The #160-D3 is a front; the #160-D4 is
a rear.
You
can either very carefully and patiently bend these to
fit; or just cut them off in a suitable spot and clamp
neoprene fuel line for the rest of the journey down.
There were some that were short from the get-go; and
on those a flaring tool was used to make a "bubble" on
the end. Doing that I've usually tried to run them so
they endup outboard of the main frame rails. If these
are just cut I would suggest using two fuel line
clamps. One is probably sufficient as the fuel is not
under pressure; but two is better.
Shipping
one or two intact would necessitate a bigger box which
will cost more and may be more to ship; if you want we
can just cut them off at any given point (approximate
number of inches long).
I
just tried to fit the original tubes on a car; they
aren't that easy either!