Fuel Filter In A Bad Place?

Discussion in 'Intake Systems , Fuel Systems and Related' started by chromebumpers, Jul 7, 2021.

  1. chromebumpers

    chromebumpers solid fixture here in the forum Staff Member

    I haven’t been getting replies to most of my posts, but I’ll keep trying.

    The last owner of my Pontiac had a metal fuel filter less than a foot from the gas tank. I replaced that when I went through the moves to restart the car after sitting so long. I drained what I could, filled the tank with premium gas and added dry gas/carb cleaner to the tank. Everything was flushed all the way to the carb and the carb was a fresh rebuild. The car started and ran.

    I see cars with filters in this position and no problems. I hear from some you shouldn’t have a filter before the pump. What is the definitive answer? Should I remove the filter after I run through the first tank full of gas?
     
  2. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    Ive always PREFERED to place the fuel filter after the fuel pump,
    but located well before the heat of the engine compartment,
    and ideally near the cars frame,
    obviously many people will ask WHY?
    well most fuel tanks have a fine screen in the fuel tank to preclude,
    and prevent major physical crap from being sucked into the fuel pump
    and fuel pumps, electrical or mechanical, pump pressurized fuel far more efficiently than they can suck fuel.
    you can get 7-13 pounds of fuel pressure from most mechanical fuel pumps used on carb equipped cars,
    but if you measure the suction they can create its anemic in comparison.
    thats one reason most electrical fuel pumps are located either in the fuel tank,
    or lower than the fuel tank, near the rear of the car or low near the cars frame,
    so gravity can help prime the fuel pump.
    yes many cars do place the fuel filter between the tank and fuel pump,
    but most pumps & filters, that do use that config ,
    do not use a extra fine micron filter mesh,
    they use screens that only filter out larger 30-50 micron or larger crud
    such as the type of filter many EFI systems use to protect injectors,
    and remember most of those systems use a pump with a strainer in the fuel tank,
    and a second fuel filter after the pump, and operate at 40-60 psi

    http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/

    http://garage.grumpysperformance.com/index.php?threads/how-big-a-fuel-pump-do-you-need.1939/
     
    Last edited: Jul 8, 2021
  3. Mark Bradley

    Mark Bradley Da guy in Newbury

    I’m in alignment with Grumpy here that after the pump is ideal.
    As an example the modern OE in tank pump units actually have a filter in them and it is on the output side of the flow (decided to cut one apart).
    In your case while it will work where it is getting fuel to flow on a dry line may be a bit of a challenge initially. If you can you should relocate it to post pump.

    As for no previous replies that seems odd as I recall replying to your previous post where you included a photo. Perhaps it was misplaced.
    Cheers.
     

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  4. chromebumpers

    chromebumpers solid fixture here in the forum Staff Member

    I never said “No previous replies”

    I said “Most”

    Many times my posts are just rhetorical, but 7 out of the last 10 non rhetorical posts looking for help have gone without a reply. No big deal, summertime is slow and even non-existent for posting. I get my answers, I just figure other people have the same questions and it enhances this site to post such things for when they do a search it can lead people here - hopefully helping membership grow.
     
    Mark Bradley likes this.
  5. chromebumpers

    chromebumpers solid fixture here in the forum Staff Member

  6. B&R Racing

    B&R Racing reliable source of info

    Florida and Deep Southern USA States have it the hardest with Ultra High Humidity Levels .
    The Humidity water vapor will be absorbed into any Gas Tank Fuel used.
    I Researched the topic alot.
    Best thing to do is take the stock Fuel Tank and Remove throw it away.
    Install a Full Drag Car Fuel system Full Return Layout.
    It's very expensive to do it right.
    In Grumpy's Archives.
    All the the past and current Stock and low budget rubber Hose Connecting fuel filters Suck Bad.
    Only can take advantage of Superior Fuel Filters designed for Racing and also work for the Street Stellar is when you plumb the entire Fuel system in #10 AN Race Hose.
    Unforgiven Jim with his Race Supercharged Small Block Chevy Cracking 840 Hp + and myself with my 1963 Pontiac Gp 455 520 Hp are the only a small handful that Tossed all went Full Race Fuel Cell Fuel system.
     
    Last edited: Sep 5, 2021
  7. B&R Racing

    B&R Racing reliable source of info

    Fuel Drag Fuel Cell also allows for Fuel shutoff valves.
    Also a Shutoff valve on the vent line.
    Fuel is 100% sealed then from moisture and the atmosphere.
     

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