On Wed, 3 Dec 2003 21:10:23 -0500, "Doug Dotson" wrote:

Steve,

I understood that you were suggesting that I leave the polishing system
running while running the engine. Since I have 2 tanks it seems to me
to require two polishing systems to keep polishing while running. The
system I have designed allows me to polish either of the two tanks
at any time and run the engine out of either tank at any time as well. So
I can polish the same one I am running out of if I wish. I guess the
choice of which to polish while running is up for grabs.

I think I'd route it so that I can route either tank to the polishing
system then 'T' the polishing system to the engine and the return to
either tank. Just make sure you're returning to the same tank you're
drawing from. A simplified version (without bypass plumbing which is a
pain to draw) looks something like this: (view with fixed point font
like courier)

-------------- /--------------------------T---------|
| Y select / return to tanks | |
---------- | --------------- |
| | |(to tank 2) | check valve | |
| Tank 1 | --------------- |
| |---------- ------------- | |
---------- | | Polishing | -------- | ----------
|from | filters | | | | \ | |
Y select /----| with |-| Pump |-T- \-| Engine |
---------- /tanks| bypassing | | | | |
| | | ------------- -------- ----------
| Tank 2 | |
| |----------
---------- out

If the above ascii drawing looks horrible, sorry. But basically, the
supply from both tanks goes to a Y valve which feeds either to the
polishing filters. That's where you'd put the bypass valves so you can
go around any filter (GCF or Racor). Then to a T where one side goes to
a shutoff valve then to the engine. The shutoff valve is so that you
can turn off fuel to the engine while you're priming the system after
changing filters so air won't get in the engine. You can also plumb it
so that the engine can draw from the tanka bypassing the filters so you
can prime them and run the engine at the same time if that's a
requirement. I didn't care about that since I don't run the engine all
that much (sailboat.) Also not shown is that you want to install vacuum
gauges, one before the GCF filter, one between the GCF and the Racor and
one after the Racor before the Walbro pump. Any difference more than a
few psi across a filter means it's time for an element change.

The other side of the T goes to a check valve. That's there so that if
the electric pump fails the engine won't suck air from the return lines.
Then there's a T where the engine return and the polishing system return
join and go to another Y valve to select where to return the fuel to.
Just make sure both Y valves are in the same position. You can also use
this as a fuel transfering pump if you want to, by putting the Y valves
in different positions. But be careful you don't overflow the tank
being filled.

Steve

Subject: Fuel transfer/polishing pump
From:

By the way, instead of saying "But that's a red herring since it's not
usually the oil pump that wears out due to dirty lubricating oil." I
should have said "But that's a red herring since it's not usually the
oil pump that wears out *prematurely" due to dirty lubricating oil."

True.
I was just using the pump to pump comparison because those are the first things
each oil sees (not counting the diaphragm pump on most diesels) as they get to
the engine. Perhaps not the best comparison.

But I still believe my point is valid.
That fuel oil needs to be filtered and kept clean to a higher degree than fuel
oil to keep a fuel injected engine running well.

Capt. Bill

Subject: Fuel transfer/polishing pump
From:

By the way, instead of saying "But that's a red herring since it's not
usually the oil pump that wears out due to dirty lubricating oil." I
should have said "But that's a red herring since it's not usually the
oil pump that wears out *prematurely" due to dirty lubricating oil."

True.
I was just using the pump to pump comparison because those are the first things
each oil sees (not counting the diaphragm pump on most diesels) as they get to
the engine. Perhaps not the best comparison.

But I still believe my point is valid.
That fuel oil needs to be filtered and kept clean to a higher degree than fuel
oil to keep a fuel injected engine running well.

Capt. Bill

Subject: Fuel transfer/polishing pump
From: "Doug Dotson"

After having my lift pump fail half way across the Gulf Stream, I think
I'll stick to what Yanmar and the mechanic in FL suggested even
beyond the warranty.

Did your sails fail too? :-)

And didn't you say you had electric priming pumps?
If so, why did you not use those to run the engine?

Capt. Bill

Subject: Fuel transfer/polishing pump
From: "Doug Dotson"

After having my lift pump fail half way across the Gulf Stream, I think
I'll stick to what Yanmar and the mechanic in FL suggested even
beyond the warranty.

Did your sails fail too? :-)

And didn't you say you had electric priming pumps?
If so, why did you not use those to run the engine?

Capt. Bill

Subject: Fuel transfer/polishing pump
From: "Doug Dotson"

Getting things shaken
up is the best thing I can hope for.

I can just see the looks on the crews faces as you say, "pray for rough
weather, I need to clean my fuel". :-)

Capt. Bill

Subject: Fuel transfer/polishing pump
From: "Doug Dotson"

Getting things shaken
up is the best thing I can hope for.

I can just see the looks on the crews faces as you say, "pray for rough
weather, I need to clean my fuel". :-)

Capt. Bill

"LaBomba182" wrote in message
...
Subject: Fuel transfer/polishing pump
From: "Doug Dotson"



"LaBomba182" wrote in message
...
Subject: Fuel transfer/polishing pump
From:

On 29 Nov 2003 20:48:01 GMT, (LaBomba182) wrote:

Subject: Fuel transfer/polishing pump
From: (Steven Shelikoff)

Not much difference between diesel and oil.

Perhaps, but there is a world of difference between the tolerances
of a
fuel
injector pump and an oil pump.

True. But that's a red herring since it's not usually the oil pump
that
wears out due to dirty lubricating oil.

Not quite. A 350 Chevy engine will run for a long time, years maybe,
with
dirty
oil.
A diesel injection pump and/or injectors with dirty fuel will not.

Capt. Bill

Invalid statement.

Really? Without foundation. How so?

Are you saying a diesel will run a long time with dirty fuel?

No, I said that a diesel will run a long time with dirty oil.

In one case you are talking about lubrication oil,
in the other your are talking about fuel.

Correct. But that does that make those statements "invalid"?

Yes.

A diesel will run quite a
long time without changing the oil just a s gas engine will.

Of course it will.
But that has no relation to how long it will run with dirty or poorly
filtered
fuel. Other than to back up just what I was saying, that lubricating oil
does
not need to be filtered as well as fuel oil to keep a fuel injected engine
running.

Absolutely.


Capt. Bill

"LaBomba182" wrote in message
...
Subject: Fuel transfer/polishing pump
From: "Doug Dotson"



"LaBomba182" wrote in message
...
Subject: Fuel transfer/polishing pump
From:

On 29 Nov 2003 20:48:01 GMT, (LaBomba182) wrote:

Subject: Fuel transfer/polishing pump
From: (Steven Shelikoff)

Not much difference between diesel and oil.

Perhaps, but there is a world of difference between the tolerances
of a
fuel
injector pump and an oil pump.

True. But that's a red herring since it's not usually the oil pump
that
wears out due to dirty lubricating oil.

Not quite. A 350 Chevy engine will run for a long time, years maybe,
with
dirty
oil.
A diesel injection pump and/or injectors with dirty fuel will not.

Capt. Bill

Invalid statement.

Really? Without foundation. How so?

Are you saying a diesel will run a long time with dirty fuel?

No, I said that a diesel will run a long time with dirty oil.

In one case you are talking about lubrication oil,
in the other your are talking about fuel.

Correct. But that does that make those statements "invalid"?

Yes.

A diesel will run quite a
long time without changing the oil just a s gas engine will.

Of course it will.
But that has no relation to how long it will run with dirty or poorly
filtered
fuel. Other than to back up just what I was saying, that lubricating oil
does
not need to be filtered as well as fuel oil to keep a fuel injected engine
running.

Absolutely.


Capt. Bill

Subject: Fuel transfer/polishing pump
From: "Doug Dotson"

If it is away from the pickup, then it isn't entering into the problem.
If things get stirred up then the polishing system will do its job
better.

Of course. But in the context of "bubbling" the fuel to "polish" it, it doesn't
do much good.

Capt. Bill