Mike Wills came up with this cute place to mount a
  fuel pressure gage. Helps when setting the fuel pressure
  or trouble shooting things when it won't start.
  These small gages are available from McMaster Carr.

  Dave, can you send me all correspondence with Mike
  as he was installing the engine. It will help
  me understand why he did certain things in a particular
  way.

    Paul Lamar

No Bourdon tube gages for fuel. Put an electric sender in that position
and a switch beside it to switch between the inside electric gage and
one under the cowl. If you just have to use a Bourdon gage you can
put an isolator in front of it and run it on antifreeze. Bourdon
tubes eventually split open and spray fuel all over hell. Lynn E. Hanover

What is it about fuel pressure that causes them to split?
Say.... as opposed to steam?

Paul Lamar

The pulsations. Gages specifically designed for fuel pressure or
other forms of pulsation have chokes with .010" holes to damp the
speed of pressure changes that can affect the tube. The tube is very
thin wall brass sheet formed into a tube and soldered. Then rolled
flat and wound into a coil.

Even those designed for fuel pressure fail with alarming regularity.
My racer came coasting into the pits one day with the window net
down and the drive holding his hand out trying to get some air into
the cabin.

The fuel pressure gage had failed and hosed down the interior and the
driver. We were very lucky. I sent it back to Autometer but never heard
a word back. I bought an isolator to put right beside the carb, and ran
the new gage on antifreeze. Then you can use 1/8" Nylon sender hose
instead of braided stainless.

Lynn E. Hanover

Does this apply to the  glycerin filled industrial versions that
damp pulsations? Mike's is 1 1/2 inch SS glycerin filled.

Autometer has a 15 psi for $22 and a $44 100 psi obviously for fuel injection.

The $22 15 psi is used for carbs with a solenoid pulsations pump
and the $44 100 psi is used with a centrifugal pump. I suspect the
centrifugal pump is much smoother.

I do not think either Autometer one is glycerin filled.

Where do you get the isolaters?

Paul Lamar --



Paul,

The glycerin filled gauges HELP damp pulsations. You do need to have a
restrictor in the sensing end to limit the amount of difference in a short
time. Re: pulsation damping. The glycerin gauges also have a vent plug in the
top. Some have a little nipple on top that you cut the top off when you put it
in service. This leaves a small vent hole. Others have a small valve the you
rotate 180 degrees to accomplish the same thing. Without the vent, the gauge
does not read correctly.

Isolators can be purchased from Swageloc and other industrial suppliers. A bit
expensive but worth it if dealing with H2S (sour gas).

As a note, another worker was killed by a leak of sour gas May 1. They were
trying to thaw a hydrate in the pipe. Killed one, two taken to hospital due to
inhaling the gas and one police officer that was manning a road block got a
whiff and was also taken to hospital. One reason  I do not want to work with
the oil patch any more. No news yet on what exactly happened.

Back to the gauges. Glycerin filled gauges fail in sour gas compressor
facilities due to the vibration and pulsations. Bourdon are also used in the
pressure controllers the regulate the inlet, outlet and sometimes inter stage
valves in the compressor package. They fail also in sweet gas systems also,
but not as dangerous. The bourdon tube eventually fails near the end that is
screwed down due to the flexing and cracks.

As Lynn recommended, I would use an electric gauge for cost and safety reasons.

Dale Davies