On Wed, 28 Mar 2007 20:36:23 GMT, "oceantom" u32897@uwe wrote:

Thanks Wayne. My tank is on deckand given the picture you painted, yours
seems to be the best idea so far-- what company made the priming pump you use?
Tom

Walbro 6802, available for less than $100 if you shop around.

On Mar 28, 3:39 pm, Wayne.B wrote:
On Wed, 28 Mar 2007 14:50:08 -0500, Don W

wrote:
I'd like to hear more about your fuel system
setup. It sounds interesting.

It's very straight forward.

I have no day tank.

Each engine has the usual engine mounted filters.

Ahead of each engine is an array of 2 Racors (total of 4), each with a
ball valve on the intake and outlet. This allows either filter to be
selected or isolated, or both filters could be in paralell.

The output side of the Racors has a vacuum guage to monitor the
condition of the filter. In the event of a higher than normal vacuum
reading I open the valves for the backup filter, and close off the
valves for the old filter. The old filter is now isolated and can be
changed on the fly.

In between the Racor's and the engine mounted filter is an electric
fuel pump which is normally valved off and unpowered. If I need to
prime the engine mounted filters, the electric pump is valved in and
turned on. This forces fuel into the engine filters and though the
injection loop to the fuel return. This could theoretically be used
for polishing but I don't because I have a separate polishing loop
with its own pump that just draws fuel through the Racors and sends it
back to the tank.

So... you just bleed the air off at the filter housing as you "prime
it"?

Joe

On 28 Mar 2007 20:14:27 -0700, wrote:

So... you just bleed the air off at the filter housing as you "prime
it"?

The DD injection system is self bleeding as long as it's receiving
pressurized fuel. Usually a minute or so with the priming pump is all
that's necessary.

On Mar 29, 5:42 am, Wayne.B wrote:
On 28 Mar 2007 20:14:27 -0700, wrote:

So... you just bleed the air off at the filter housing as you "prime
it"?

The DD injection system is self bleeding as long as it's receiving
pressurized fuel. Usually a minute or so with the priming pump is all
that's necessary.

Thats OK as long as your engine is not to hot, and it does not take
to long to get all the air thru the system. DD injectors use fuel flow
to keep them cool.

Joe

On 29 Mar 2007 06:35:08 -0700, wrote:

The DD injection system is self bleeding as long as it's receiving
pressurized fuel. Usually a minute or so with the priming pump is all
that's necessary.

Thats OK as long as your engine is not to hot, and it does not take
to long to get all the air thru the system. DD injectors use fuel flow
to keep them cool.

You don't run the engine when priming so heat is not an issue. Most
times if I'm using the priming pump it's because I changed one of the
engine mounted filters which I always do cold anyway.

On Mar 29, 9:47 am, Wayne.B wrote:
On 29 Mar 2007 06:35:08 -0700, wrote:

The DD injection system is self bleeding as long as it's receiving
pressurized fuel. Usually a minute or so with the priming pump is all
that's necessary.

Thats OK as long as your engine is not to hot, and it does not take
to long to get all the air thru the system. DD injectors use fuel flow
to keep them cool.

You don't run the engine when priming so heat is not an issue. Most
times if I'm using the priming pump it's because I changed one of the
engine mounted filters which I always do cold anyway.

What if both filters clog offshore?
You going dead in the water in a storm while swapping filters?

I thought that was the purpose of having two filter housing and piping
them to shift from housing to housing.

Joe

wrote:

Actually there is a better way to do it. On my main I have a quart
size bleed tank mounted at the highest spot in the fuel loop. All you
do is start the main, let all the air collect in the chamber and vent
all air off the top through a clear hose into a tank for filling the
housings. You can see it in the picture on top the engine with the
loop of clear hose, sorry you can not see the valve.

http://sports.webshots.com/photo/242...63212926AEgQPt

Joe,

I've been running and working on diesels for about
35 years now, but I'm having a little trouble
understanding how your fuel setup works. From
what you wrote, I think that you have a small tank
mounted on the fuel return loop above the engine.
How does that help you if you have air in the
injector pump? Obviously, I'm missing something.

Don W.

It's between the pump and injectors. So when air comes out of the
housings it bubbles up into the chamber, all the injectors draws from
is the bottom of the chamber. So the chamber is pressurized and
collects a head of air because it is the highest point in the fuel
loop, which you open a valve to bleed off until you have no more air
or bubbles. I've been working with diesels just as long, and my boat
is the first time I've seen such a set-up. Works great, I've never
gotton even a bubble of air into the injectors, and have had some
really rough sloppy weather filter changes.

Joe

What I was missing is that you are running a
Detroit Diesel with electronic fuel injection ;-)
This technique won't work for my Yanmar because
it is ancient technology with a mechanical
injector pump and passive injectors.

Sounds like it works well on your setup.

Don W.

Wayne.B wrote:

I'd like to hear more about your fuel system
setup. It sounds interesting.

It's very straight forward.

I have no day tank.

Each engine has the usual engine mounted filters.

Ahead of each engine is an array of 2 Racors (total of 4), each with a
ball valve on the intake and outlet. This allows either filter to be
selected or isolated, or both filters could be in paralell.

The output side of the Racors has a vacuum guage to monitor the
condition of the filter. In the event of a higher than normal vacuum
reading I open the valves for the backup filter, and close off the
valves for the old filter. The old filter is now isolated and can be
changed on the fly.

In between the Racor's and the engine mounted filter is an electric
fuel pump which is normally valved off and unpowered. If I need to
prime the engine mounted filters, the electric pump is valved in and
turned on. This forces fuel into the engine filters and though the
injection loop to the fuel return. This could theoretically be used
for polishing but I don't because I have a separate polishing loop
with its own pump that just draws fuel through the Racors and sends it
back to the tank.

This sound a lot like what I'm thinking about,
except for the lack of a day tank. Sounds like
you thought it through pretty well when you
designed it.

Don W.

On 29 Mar 2007 08:30:02 -0700, wrote:

What if both filters clog offshore?
You going dead in the water in a storm while swapping filters?

I thought that was the purpose of having two filter housing and piping
them to shift from housing to housing.

You must be misunderstanding something. Because of the dual
switchable Racors in front of the engine it is very unlikely that
either of the engine mounted filters will ever clog. I replace them
periodically as routine maintenance only.

The Racors require no priming.

Since I have twin engines fed by separate tanks and filters the
probability of ever going dead in the water is very slim.

In article . com,
wrote:

On Mar 28, 12:05 pm, "oceantom" u32897@uwe wrote:
Does anyone have any information or advice on whether or not a racor
element
filter can be installed above the fuel tank on a V8-71 detroit diesel?
Thanks

My advice is to install them below fuel level. Makes changing filters
and purging air mucho easier.
Nothing worse then an air bound detroit.

Mount them above and chances are you will become a Detroit fuel rack
expert in no time;0)

Joe


Here is the way I have my Powerhouse Fuel System setup, which could be
used aboard a vessel.

Main Tank is 500 USG Dike Tank with Water Trap built into a trough along
the bottom of the tank, that feeds a Water Drain Valve. Fuel Outlet
is at 3 Inches above the Water Trap, and extends 12" into the Tank.
Fuel leaves the outlet and then feeds twin RayCor 2020's in parallel
with Isolation BallValves, and then feeds the PowerHouse Fuel Manifold,
which the GenSets then Draw from. Each Genset has it's own Isolation
BallValve, Primary Raycor RS43C Primary, Engine driven Fuel Lift Pump,
and Baldwin Secondary Fuel Filters, Prior to the Injection Pump. The
Individual GenSet Return Lines feed individual Isolation BallValves,
that then feed the PowerHouse Return Manifold, which then feeds the
top of a 50 USG Tank with and Overflow Line 1" below the top of the tank,
that then feeds back to the Main Tank. The Output Line from the
50USG Tank has a Isolation BallValve that then feeds back to the
Powerhouse Fuel Manifold.

This setup allows for the 50USG tank to act as an Emergency Fuel Supply
for the PowerHouse, should something go wrong (Like getting 25 gallons
of water pumped into the Main Tank) with the fuel in the Main Tank or
the Twin Raycor 2020's. The 50USG Tank is filled and keeped "Topped off"
by the Fuel Return System, so all fuel in it, is "Polished" by having
transitted the Raycor 2020's, and the Primary and Secondary Fuel Filters,
at least once. 50 USG is about 3 Days operation, so I have at least
three days to research any problem, and fix it, before the lights go out.

Bruce in alaska
--
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