Following the Sun, Gauges

For discussing the modifications needed for diesel vehicles to run with 2 tank veggie oil conversions.

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Following the Sun, Gauges

Postby mortarsprayer » Thu Oct 02, 2008 12:27 pm

Hello Listers.
I have a mechanical oil pressure gauge between the veggi filter and IP. ( See Sun's Diagram)
The first day while there was a small amount of air in the gauge hose, the gauge was pulsing but readable. Now that the system is fully bled the gauge needle is taking the direct hit of the lift pump and flutters so fast it is useless.
The guage will not last long like this.

Does your gauge act the same? What did you do to fix this?

Thank you,
Nolan
Nolan
95 Dodge Cummins 3500 Flatbed, dump.
Started life as chassis cab, 2WD automatic pos, converted to 4WD with 5 speed that pulls like a freight train.
mortarsprayer
 
Posts: 42
Joined: Sun Aug 03, 2008 7:11 am

Postby SunWizard » Thu Oct 02, 2008 12:36 pm

Yes the Cummins puts out large pulses. I used a brass needle valve in the line to the guage. www.mcmaster.com 7833K73 Medium-pressure Needle Valve W/metal Seats, Brass, 1/8" Npt Male X Female. No more pulses.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
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Postby mortarsprayer » Thu Oct 02, 2008 12:55 pm

Thank you Sun.
A needle valve will allow me to turn off the gauge to save it but the swing is now so fluttery that I can not get good data from it. It has an engine speed oscillation between 15 and 50 PSI. It is going so fast, you can actually HEAR the needle pulsing back and forth!

Is yours this extreme? How often do you open the valve to check the filter condition?

It was steadier in the beginning with a little air cushion in the line. Perhaps I should add small 'anti hammer' air space between a needle valve and the gauge.

I wonder what the sampling rate of a digital gauge would be. Would that work better?

Any other suggestions?


Best regards,
Nolan
Nolan
95 Dodge Cummins 3500 Flatbed, dump.
Started life as chassis cab, 2WD automatic pos, converted to 4WD with 5 speed that pulls like a freight train.
mortarsprayer
 
Posts: 42
Joined: Sun Aug 03, 2008 7:11 am

Postby SunWizard » Thu Oct 02, 2008 1:52 pm

You don't close it completely, you adjust it closed just enough that your guage reads a steady pressure, and it still responds to changes. Yes mine pulses from 5 to 40 without it. Digital isn't much better.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1719
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby mortarsprayer » Fri Oct 03, 2008 8:12 pm

Hello Sun.
I picked up a needle valve today. I also learned about and ordered a pressure snubber similar to: http://www.raysnubber.com/
These are supposed to go a long ways towards smoothing out a gauge.
it is a MxF fitting with a sintered bronze insert.

A McMaster number for a similar snubber is 3820K26

The engineer I talked with (Andy 800-822-0804) also suggested using a liquid filled gauge for additional dampening.

Thanks for all the help.
Nolan
Nolan
95 Dodge Cummins 3500 Flatbed, dump.
Started life as chassis cab, 2WD automatic pos, converted to 4WD with 5 speed that pulls like a freight train.
mortarsprayer
 
Posts: 42
Joined: Sun Aug 03, 2008 7:11 am

Postby mortarsprayer » Sat Oct 04, 2008 4:30 pm

Hello Sun,
The needle valve worked great. It is the highest point of the system sticking straight up from the Tee. It collects any air in the gauge line which helps calm the fluttering. The valve also acts as a bleeder if I remove the gauge hose.

The whole package just keeps getting better.

Thank you for the help.
Nolan
Nolan
95 Dodge Cummins 3500 Flatbed, dump.
Started life as chassis cab, 2WD automatic pos, converted to 4WD with 5 speed that pulls like a freight train.
mortarsprayer
 
Posts: 42
Joined: Sun Aug 03, 2008 7:11 am


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