[ROVERNET - UK] Vacuum gauge

[Fletcher]

Steve-
For tuning/troubleshooting, a vacuum gauge needs to be very sensitive, 
so you can see stuff like sticky valves and such. But, for use in 
driving, as an economy gauge, it needs a lot of damping. This is done by 
connecting with small bore tubing, and may still need more damping. Lots 
of Britcars have fuel traps in vacuum lines. These are little cans, 
about 3/4" dia x 3" long, with 1/8" tube connections on each end, that 
are designed to keep fuel (condensed from vapor) out of things like vac 
advance units. They also are good dampers, since the small line feeding 
a large volume then out via small line makes a damper.
Standard on all manner of MG, Triumph, etc, and available from usual 
suppliers. I've also seen similar on late American stuff, or you can 
make them. Small engine fuel filters are pretty good for this. The 
vacuum tapping can be anywhere in the manifold, from the balance tube is 
best as vac is most even there. Off the brake hose is fine so long as 
you don't compromise the hose.
Beautiful car, and I like the paint. One of mine was light blue, and I 
resprayed the parts you have white in dark blue = "Too Blue Rover"
But, please get rid of those air filters! They are seriously restrictive 
AND they don't filter worth squat. I have had no end of problems over 
the years with carbs getting filthy from these on customer cars. It will 
wear out the engine from both dirty air and excessive fuel washing down 
the bores. In fact, I have an MGB in here now with just that problem, 
They REALLY are awful or "engine lethal".
FRM