MoparFins

Techical Discussions => Tech- - FUEL => Topic started by: attkrlufy on March 05, 2012, 06:28:33 AM

Title: Filter Placement
Post by: attkrlufy on March 05, 2012, 06:28:33 AM
I know this is a rookie question, but I've noticed that the fuel filter is not always in the same place on the tank-pump-carb circuit.  I always thought the filter protected the guts of the fuel pump - which is why most of the ones I've seen are located before the fuel reaches the pump.  That's certainly the case on my car.  However, I've seen lots of engines - including a ton of older slant sixes - where the filter is AFTER the pump, and just in front of the carb.

So....is there a proper place for the fuel filter?  Because if I could change its location on my engine, I would.  It's current location makes it a real PITA to change.

Title: Filter Placement
Post by: Guests on March 05, 2012, 07:17:39 AM
Usually, the particles getting from the tank to the carb are small enough that they don't affect the fuel pump itself because the pump doesn't have a restrictive size like the jets or injectors once they reach the engine itself. If the particles were large enough to harm the pump itself, chances are they would not make it through the fuel line itself, larger particles simply stay on the bottom of the tank and collect there. Between the pump and carb is the best location, that way gravity also plays a little bit of a role in keeping the larger garbage from moving up and against gravity under most circumstances.
Title: Filter Placement
Post by: Snotty on March 05, 2012, 11:49:00 AM
My 440 has two, one before the pump and one after.  The 413 was the same way.  I would say the best way to know how you car's set-up is supposed to be is to look at a factory service manual for your car.
Title: Filter Placement
Post by: Brian on March 06, 2012, 11:32:54 AM
For years I have been running a cheapy clear plastic inline filter before the fuel pump...then a metal canister style one between the fuel pump and carb.  Haven't had any problems.


Title: Filter Placement
Post by: firedome on March 06, 2012, 04:09:33 PM
Hey Dom, How's the Philly gig goin'? What van did you get?

Seems like usually before the carb is where you see them in my experience.




firedome2012-03-06 21:10:20
Title: Filter Placement
Post by: attkrlufy on March 09, 2012, 08:14:17 AM

Quote from: firedome
Hey Dom, How's the Philly gig goin'? What van did you get?
Philly's treating me well....it's the BANKS that is making me lose the paltry amount of hair I have left on my head.

I picked up a 2001 Ram 1500 shorti w/ 3.9L V6 and 3-speed.  It only had 30K miles on it and came with utility bins, steel bulkhead, window cages, and ladder racks already installed.  It's rust-free and ding free and super clean.  And the best part - it only cost $3,600!  :)  I know, right?!  What a deal!

Title: Filter Placement
Post by: attkrlufy on March 09, 2012, 08:17:19 AM
It's just occurred to my why the older cars seem to have the filter higher up (closer) in the line to the carb, while my 1979 has it lower down - before the pump.  Those cars don't have a fuel line return.

BUT - it is good to know that the filter can come "after" the pump.  I think next summer I'll change the filter's location to make it easier to get to.  It really is in an awful place, currently.  Very hard to reach.


Title: Filter Placement
Post by: Guests on March 09, 2012, 08:33:03 AM
Well, having them after the fuel pump also helps prevent fuel from pouring out of the fuel tank when changine, something that requires parking on a steep hill to reduce the amount of fuel lost and getting all over the place, usually not an occurence when the filter is higher on the engine after the fuel pump.
Title: Filter Placement
Post by: firedome on March 09, 2012, 12:26:54 PM
That DOES sound like a great deal... but won't stay ding free long
around there I'd think!  Let me know if you'll be in Ithaca
anytime!