Fuel Filter Location

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DartGTDan

DartGTDan

'71 Dart GT Fan
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What is the proper location for a fuel filter on a '71 318? Between the fuel tank and the fuel pump? Or, between the fuel pump and the carburetor? Which is the better location?
 
DartGTDan said:
What is the proper location for a fuel filter on a '71 318? Between the fuel tank and the fuel pump? Or, between the fuel pump and the carburetor? Which is the better location?
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Every Mopar I have ever owned, it is installed after the pump in the line going up to the carb.
 
Is there any good argument for putting it before the fuel pump? Especially considering old fuel tanks/crud?
 
might as well put it after the fuel pump. It's ultimately going to do the same thing as if you put it before the pump and that is, filter the fuel.
 
Trevor B said:
Is there any good argument for putting it before the fuel pump? Especially considering old fuel tanks/crud?
Click to expand...

I wondered this also because that is the way mine is set up. Rubber line with the filter in it from the fuel line to the pump and a solid metal line from the pump to the carb. NOTHING on my car is original though.

gilberttitan08 said:
might as well put it after the fuel pump. It's ultimately going to do the same thing as if you put it before the pump and that is, filter the fuel.
Click to expand...

Except if you put the filter before it would keep crap from getting to the pump and possibly damaging it? Just thinking out loud.
 
Except if you put the filter before it would keep crap from getting to the pump and possibly damaging it? Just thinking out loud.[/QUOTE]

Right, good point.
 
Pumps do a much better job of overcoming resistance to flow on the outlet than the suction side.* That's a big reason the in-line filter goes after the pump. There already is the 'sock' filter on the pickup itself, so the pump will not get any sizable dirt unless the line is rusty. Since the sock is large and fully submerged, its generally not creating any resistance to flow.

It's also helpful to locate the filter so its exit is higher than its inlet. This way any vapor pockets that form exit. You could see this on the aftermarket glass filter housings. On cars with vapor return lines, the concept is similar. Place the filter or vapor seperator so the exit to the return line is at the highest point.

*On the suction side the fluid will expand as the pressure drops. With gasoline, if warm, some portion may even vaporize.
 
Mine is like just like BrianT stated:

I wondered this also because that is the way mine is set up. Rubber line with the filter in it from the fuel line to the pump and a solid metal line from the pump to the carb. NOTHING on my car is original though.

However, my car is VERY original, that's why I'm wondering. But, if it's easier for the pump (and for me to replace it) I'll put it between the pump and carburetor.
:cheers:
 
Dan,
Seeing that your car is very original, take a look in a '71 Service Manual (maybe an owners manual). In the first section of the shop manuals I have ('67, '68, '69) there are illustrations showing where to find the fuel filter. For '69 they show; slant six - nearly horizontal about 1/2 way between carb and front of engine; LA - about 35 degrees, about 6-10" above and between heater hose inlet and outlets on the intake; R/RB - nearly vertical to the side of the water pump.

- Matt
 
Coarse filter (about 100 micron) before the pump (to keep the big chunks out of the pump without putting too much restriction on the suction side), and a finer filter (about 40 micron) after the pump to protect the carb.

The factory did this with a "sock" filter in the tank and an inline filter after the pump. If you already have a sock filter in the tank, then you don't want or need another filter before the pump.
 
Trevor B said:
Is there any good argument for putting it before the fuel pump? Especially considering old fuel tanks/crud?
Click to expand...


No, the fuel pump is gravity fed. A fuel filter before it will add restriction to the line and make it harder for the pump to get the fuel to it. :wack:

It's better to put it AFTER the pump, where it is pressurized and can handle a little restriction better than the gravity fed side.... :cheers:

It helps prevent fuel starvation in the upper RPM bands.... :eek:ops:
 
I think any filter second to the OEM sock in the tank would be too much restriction on the suction side. There is very little suction there.
 
Mattax said:
Dan,
Seeing that your car is very original, take a look in a '71 Service Manual (maybe an owners manual). In the first section of the shop manuals I have ('67, '68, '69) there are illustrations showing where to find the fuel filter. For '69 they show; slant six - nearly horizontal about 1/2 way between carb and front of engine; LA - about 35 degrees, about 6-10" above and between heater hose inlet and outlets on the intake; R/RB - nearly vertical to the side of the water pump.

- Matt
Click to expand...

Mattax,

I'm not worried about keeping the car "original". Besides, I ruined the "original" when I added the SSBC front disc brakes, MP Performance electronic ignition, the '70 hood scoops & rallye wheels, etc...

I can't afford the numbers matching game, but I do appreciate and respect those who choose to do so.
 
Dan,
No problem. Yes, I thought you might be trying to keep it looking original. I find even when not, its often useful to see what the factory did to use as a starting point.
- Matt
 
I have a 71 Dart 318 2 Barrel I also have the rare Rochester carburetor on it my filter is before the pump like yours works fine they're so I never changed it I've owned this car since 2003
. I am switching over to the Mopar metal filter though it's probably safer then the clear plastic
 
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