Fuel Filter Gauges - Necessary or Not?

[Wotname]

Originally Posted by Roy M

The Racor gauges are mechanical. I will be using a pretty long run of vacuum hoses for the two gauges at the fly bridge. If that doesn't work out, I'll go to copper tubing, but I'm not expecting any issues.

I'm currently waiting to speak with a Parker/Racor tech to confirm the vacuum hose run. If it doesn't pencil out, we will still be using the vacuum switch to make an electrical alarm circuit to warn us that something nasty is about to happen. I like having the gauge so as to have the most complete and early notification of the filter status, but it's nice to have the pure electric as a second option. I'll get back with the results later, as the West Coast Racor techs don't open until three hours from now.

I would certainly be interested in the Racor's response.

My purely theoretical take is the a long run of vacuum tubing is, at the best, adequate and the copper or SS tubing would be significantly better in sense reducing potential failure modes. As we know, fuel delivery to the engine is critical . Best practice surely must be using an electrical solution with the sensor mounted right at the output of filter. Any failure of the electrical side would not impinge on the fuel delivery. In essence, the concepts and the risks are the same as the monitoring of oil pressure. I pretty sure no one would run mechanical oil pressure gauges to the bridge.

BTW, I concur totally with alert and alarm techniques you previously posted!

[Wotname]

Originally Posted by HappyMdRSailor

Agreed !

Also....

Electrically... There's a bazzilion options... most of 'em prolly under $30-50 for an ebay effort to narrow the final design...

Elaborate pls…

I haven't found anything really suitable for electrically monitoring diesel pressure around 15 psi (absolute). I.e. within a couple of inches of Hg either side of standard atm. pressure.

The previous sender I noted seems to fit the bill exactly with the exception of displaying it's output. It outputs a linearly varying DC voltage from 0.5V to 5V for absolute pressures from 0 to 30 psi and is suitable for diesel media.

While I could use a simple 5V FSD voltmeter or even an expanded scale custom voltmeter from say 1 to 3 volts, I now thinking of displaying it digitally and perhaps even using two such senders, one for fuel vacuum (0 to 30 psi) and the other for oil pressure (0 to 100 PSI sender) and displaying both on a small digital display. A clever person could incorporate user settable alarm trips in the design.

Something along the lines of the TM4 temperature monitor { http://enginewatchdog.com/TM4-twin-vehicle-order.html } except for pressures (let's call it a PM4 )

So by adding a dual temp. monitor and a dual pressure monitor to say something like my basic 2GM20 or similar engine would be a cheap(ish) upgrade to the Yanmar basic idiot lights and alarms (over temp and low oil pressure). It would electrically supply real time temps of head and exhaust with real time pressure of fuel filter and oil pressure.

Thoughts anyone ?????

[Snowpetrel]

I'd buy a PM 4, sign me up for kickstarter

Sent from my HTC_0PCV2 using Cruisers Sailing Forum mobile app

[HappyMdRSailor]

Originally Posted by Wotname

Elaborate pls…

I haven't found anything really suitable for electrically monitoring diesel pressure around 15 psi (absolute). I.e. within a couple of inches of Hg either side of standard atm. pressure.

The previous sender I noted seems to fit the bill exactly with the exception of displaying it's output. It outputs a linearly varying DC voltage from 0.5V to 5V for absolute pressures from 0 to 30 psi and is suitable for diesel media.

While I could use a simple 5V FSD voltmeter or even an expanded scale custom voltmeter from say 1 to 3 volts, I now thinking of displaying it digitally and perhaps even using two such senders, one for fuel vacuum (0 to 30 psi) and the other for oil pressure (0 to 100 PSI sender) and displaying both on a small digital display. A clever person could incorporate user settable alarm trips in the design.

Something along the lines of the TM4 temperature monitor { TM4 Twin Vehicle Order Form } except for pressures (let's call it a PM4 )

So by adding a dual temp. monitor and a dual pressure monitor to say something like my basic 2GM20 or similar engine would be a cheap(ish) upgrade to the Yanmar basic idiot lights and alarms (over temp and low oil pressure). It would electrically supply real time temps of head and exhaust with real time pressure of fuel filter and oil pressure.

Thoughts anyone ?????

Any 4-20ma (or 0-Xvolt) indicator coupled with a few transducers... Even a PLC if you want to go control crazy (tough to find weatherproof tho)

Mann Industries LPD350 Loop Powered Display Input 4 20mA | eBay


Honestly, you could run a couple of cheap mechanical turbo boost gauges for under $25... Right in the wheelhouse of range, and surely compatible with fuel... Even if they weren't, your only using the compressed or "sucked" air in the 1/8" PE line, not fuel...
LED 2" 52mm Bar Turbo Indicator Boost Vacuum Press Gauge Meter 12V US SL 0J5E | eBay

[Wotname]

Originally Posted by HappyMdRSailor

Any 4-20ma (or 0-Xvolt) indicator coupled with a few transducers... Even a PLC if you want to go control crazy (tough to find weatherproof tho)

You are just getting back at me after the Fuel Filter Wrench Saga

Now I have to go and learn and understand 4-20 mA circuitry and design

Mann Industries LPD350 Loop Powered Display Input 4 20mA | eBay

Aussie made - must be good
Honestly, you could run a couple of cheap mechanical turbo boost gauges for under $25... Right in the wheelhouse of range, and surely compatible with fuel... Even if they weren't, your only using the compressed or "sucked" air in the 1/8" PE line, not fuel...
LED 2" 52mm Bar Turbo Indicator Boost Vacuum Press Gauge Meter 12V US SL 0J5E | eBay

Call me pedantic but I hate the idea of something like this hanging off the critical fuel delivery piping .
One small failure and in rushes the air straight into the injector pump...

[Roy M]

Wotname, I haven't heard back from the Racor guys, but given your concerns about air entry, I think your best bet is to simply install the Racor vacuum switch at the filter, using a pipe tee. Then run a 14-2 cable (as long as you need it) to your bridge or cockpit, and install an LED light and piezoelectric buzzer in a prominent location. I'm having second thoughts, myself, on installing double vacuum hoses of the length that will be necessary for the journey from the port and starboard engine compartments, up through considerable twists, turns, and distance to the bridge control panel. Best to just have the alarms and lights to warn when the vacuum level approaches warning level. The result will be the same: the skipper will hot-foot it down to the appropriate engine (port or starboard) and turn the lever to a fresh filter body, thus turning off the alarm(s). Thanks for the worthy dose of paranoia. It will be easier to install, as well as being more trustworthy.

[Wind River]

My boat has a 120hp Ford Lehman with two Racor 500's in series with a vacuum gauge between the second filter and the pump. The first Racor has a 10 micron element and the second has a 2 micron element. Beyond that there is two more filters that are mounted on the engine (10 micron each, I think). I leave these in line for that time when an emergency arises and I need to bypass the Racors, I will still have filtering available.

Something to note is that the volume of fuel flow will affect the vacuum readings. These pictures are of the two Racor filters changed after a two hour long fuel polishing session and 40 hours of engine run time.

The vacuum readings on my gauge were 8" with this bad of a filter while polishing the fuel. With two new filters (still in polishing mode) the vacuum reading was 5" of vacuum. With this clogged filter and the engine running there was less than 2" of vacuum at idle. I did not check it while the engine was running under load.

My point is, this filter looks pretty clogged to me and it did not give any indication of a problem at the vacuum gauge while the engine was idling. Maybe it would have been a different if I had a gauge at the helm to see it while underway.

Now I use the 5" of vacuum during polishing mode as a base line to judge the condition of my filter before leaving the mooring. If I see 8" of vacuum, it is time for a change.

[Wotname]

Originally Posted by Wind River

.....

Something to note is that the volume of fuel flow will affect the vacuum readings. These pictures are of the two Racor filters changed after a two hour long fuel polishing session and 40 hours of engine run time.

The vacuum readings on my gauge were 8" with this bad of a filter while polishing the fuel. With two new filters (still in polishing mode) the vacuum reading was 5" of vacuum. With this clogged filter and the engine running there was less than 2" of vacuum at idle. I did not check it while the engine was running under load.

My point is, this filter looks pretty clogged to me and it did not give any indication of a problem at the vacuum gauge while the engine was idling. Maybe it would have been a different if I had a gauge at the helm to see it while underway.

Now I use the 5" of vacuum during polishing mode as a base line to judge the condition of my filter before leaving the mooring. If I see 8" of vacuum, it is time for a change.

Thanks for confirming something that I had suspected. For meaningful analysis of the vacuum, the reading should made at normal operating rpm.

Just another reason to have the gauge outside the engine bay unless you have resident engineer, below

[HappyMdRSailor]

Quote:
Originally Posted by HappyMdRSailor View Post
Any 4-20ma (or 0-Xvolt) indicator coupled with a few transducers... Even a PLC if you want to go control crazy (tough to find weatherproof tho)

You are just getting back at me after the Fuel Filter Wrench Saga

Now I have to go and learn and understand 4-20 mA circuitry and design

Mann Industries LPD350 Loop Powered Display Input 4 20mA | eBay

Aussie made - must be good
Honestly, you could run a couple of cheap mechanical turbo boost gauges for under $25... Right in the wheelhouse of range, and surely compatible with fuel... Even if they weren't, your only using the compressed or "sucked" air in the 1/8" PE line, not fuel...
LED 2" 52mm Bar Turbo Indicator Boost Vacuum Press Gauge Meter 12V US SL 0J5E | eBay

Originally Posted by Wotname

Call me pedantic but I hate the idea of something like this hanging off the critical fuel delivery piping .
One small failure and in rushes the air straight into the injector pump...

I found myself pretty tied up bouncing around CF to get to the wrench project yet.... AND... The only thing actually clean in the shop is the mill...

I picked the first Southern Hemisphere listing specifically for your entertainment!

Transducers, indicators, and PLC's are found for pennies now... Some complicated, some not... (I recently spent 4 hours reprogramming a 4 event cycle into an old PLC that should have taken me 15 min)

I wouldn't worry about air induction in vacuum lines... connections can be made extremely secure... If it's the PE or Nylon tubing that worries you, 1/8" copper is cheap.... But I personally would run plastic ...

You could also simply throw a few T's in the circuit with SIMPLE pressure/vacuum switches and have a Christmas tree indicator panel...

[Wotname]

To those still following this thread and have FF gauge already fitted,, I have a supplementary question

What is your normal operating vacuum, your normal range and the point where you consider a filter change?

I am working up a design for a custom electrical gauge and need to know real world numbers. From the numbers I see on mechanical gauges I'm thinking that a range of say 0 to 6 or 8 inches of Hg (-3 or -4 psi) would be ideal. I repeat this is still theory for me, I have never had a FF gauge in the past so any input is helpful. I am also presuming any positive pressure (gravity feed etc) doesn't really need to be considered but perhaps a range of say +1 to -4 psi (-0.5 to +2 "Hg) should be considered. I think it is best to keep the range as small as possible so that small variations can be observed.

[Wotname]

Originally Posted by Snowpetrel

I'd buy a PM 4, sign me up for kickstarter

Sent from my HTC_0PCV2 using Cruisers Sailing Forum mobile app

You are signed up for beta testing

Would you like an analogue display (perhaps with red & green arcs as well as the numbers)) or a digital display? Actually you may not get the option (yet!) as I much prefer analogue - as a they are IMO easier to read with quick chance or scan. I not smart enough to provide a analogue arc as part of a digital display but if others are, all help is welcome!

[Wotname]

Originally Posted by HappyMdRSailor

………..

I picked the first Southern Hemisphere listing specifically for your entertainment!

Thanks, interesting ebay site also, it looks like they flog off donated(?) stuff for a SE Asia charity. Most of seems to ex mining or oil & gas stuff.
………...
I wouldn't worry about air induction in vacuum lines... connections can be made extremely secure... If it's the PE or Nylon tubing that worries you, 1/8" copper is cheap.... But I personally would run plastic ...
………….

Hmm… you experience is somewhat different from mine w.r.t. non metal tubing. Most small / light general aviation use PE or nylon tubing for their pitot and static air systems (airspeed and altitude), IME they fail reasonably often. Some of the runs are complex and I run a mile when they report problems as chasing small leaks is time consuming and frustrating (at the best). And a leak in their systems doesn't shut the engine down

I accept that metal (Cu or Al) tubing is far superior, at least it is IME.

YMMV

[GrahamHO]

I appreciate what you are all trying to achieve with a pressure gauge. I didn't realise that blocked filters could be so common. I wonder if the same energy that is put into detection could better be put into keeping the fuel clean in the first place. I recall seeing large funnels that have a filter built in, once being used to refuel small aircraft. Also how vulnerable are your filler caps to letting water in? Maybe in a location with dodgy fuel the primary filter elements should be changed regularly. Then an inspection of the old element will tell you something.

I don't think blocked fuel filters is a problem with long distance trucks so why is it a problem with our boats? A truck might use in one day more diesel than I would use in a few years. Do trucks fit a fuel filter pressure gauge? I don't know.

[Capt Gill]

Originally Posted by Wotname

You are signed up for beta testing

Would you like an analogue display (perhaps with red & green arcs as well as the numbers)) or a digital display? Actually you may not get the option (yet!) as I much prefer analogue - as a they are IMO easier to read with quick chance or scan. I not smart enough to provide a analogue arc as part of a digital display but if others are, all help is welcome!

Count me in on the Beta and definitely analog. My present Racor gauge is has a range of 0 hg to 30 hg with colour white ranging 0-7 hg, yellow 7-10, red 10-30. I guess Racor didn't see a need to account for positive press. Gravity feed or installing the Racor downstream of the lift pump would be an issue. I don't want a mech. gauge any further away than it is(top of the filter).

[Capt Gill]

Originally Posted by GrahamHO

I appreciate what you are all trying to achieve with a pressure gauge. I didn't realise that blocked filters could be so common. I wonder if the same energy that is put into detection could better be put into keeping the fuel clean in the first place. I recall seeing large funnels that have a filter built in, once being used to refuel small aircraft. Also how vulnerable are your filler caps to letting water in? Maybe in a location with dodgy fuel the primary filter elements should be changed regularly. Then an inspection of the old element will tell you something.

I don't think blocked fuel filters is a problem with long distance trucks so why is it a problem with our boats? A truck might use in one day more diesel than I would use in a few years. Do trucks fit a fuel filter pressure gauge? I don't know.

I'm assuming proper maintenance,but not rote maintenance regarding this issue,because conditions are variable.
Long distance diesel trucks don't have a problem(normally)with fuel standing in their tanks for long periods and the marine environment is much harsher than on land.