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Fuel System Basics and Filtering Options

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  • Fuel System Basics and Filtering Options

    Fuel System Basics and Filtering Options

    The stock Model A fuel filtering consists of a stand up pencil type filter screen on top of the tank shutoff valve which sits inside the tank, (these pencil filters were not used when the car was built) a cast iron or glass sediment bowl and an inlet screen at the carburetor. The late 31 indented fire wall models have the shut off valve under the hood and uses a side bowl type carburetor to filter it. A badly rusted tank should be removed cut open and cleaned out, Brent Terry is one of the few that do it this way, here is his site link http://www.model-a-ford.com/
    Others have sealed their tanks with mixed results as today's modern fuels tends to attack certain types of available coatings. I have used evapo-rust with good results for dissolving rust, with that being said another good alternative is to just find a good used tank. Timothy Kelly came up with this dirty leg trick that many have used to trap the garbage, but this could be an ongoing process if the main cause is not.addressed properly . Here is the Ford Garage site link to Tim's setup, http://www.fordgarage.com/pages/kellyshutoff.htm
    A tight / hard to turn or not sealing shut off valve can be caused by debris being caught up in it.These can either be rebuilt or replaced, but always install a new pencil screen in the valve as originally they were not used. These pencil filter are your first line of defense to prevent particles from going down stream. If your taking the rebuild route many folks have had success lapping the parts with toothpaste, but inspect for scoring or galling on the ball. There is an optional fuel filter that can be installed in the glass style sediment bulb. These glass bulb filters do not restrict the flow to the carburetor as some of the in lines do. The NAPA number is 3034 and the WIX number is 33039 or you can cross-reference these to your favorite brand. The suppliers such as Bert's Model A https://modelastore.com/ now also sell this style filter FYI. These filters are suspended by the glass bowl itself, it sits in the depression at the top of the glass. Therefore no spring or such is needed below the filter to hold it up against the incoming fuel. . The main fuel feed into the sediment bowl is down through the center where the original screen has a hole. Any junk will flow in through there and get trapped in the filter before it goes out through the mesh screen. Leaving the original mesh screen in place is a good idea as this will act as a double back up per say. Install the items in this order,
    Sit the filter into the bowl first having it rest on the depression
    Install a new cork bowl gasket up into the sediment upper housing with the screen above it. Always try to use a cork gasket instead of neoprene as the cork tends to hold up better with the crap gas we have now a days.
    Please refrain from using the inline type filters where you cut the feed line between the sediment bowl and the carb and use rubber hoses. These type of filters have been known to impede the natural gravity flow of the fuel and they can also be a fire hazzard since some of these are plastic, plus having the rubber lines near the hot exhaust manifold is also a bad idea.
    Lastly there is a screen at the fuel inlet of the carburetor which is sometimes forgotten about




    pencil filter:::::carburetor inlet screen filter:: WIX 33039, NAPA 3034 sediment filter
    13280_2_1.jpg14260_2_1.jpg33039.jpg



    image_757.jpg
    1~1931 Tudor ~ Dad
    2~1930 Tudor's ~ Lucy & Paul


    Henry Ford said
    "It's all nuts and bolts"


    Mitch's Auto Service ctr

  • #2
    More fuel filtering info


    If you install a new needle and seat and the carb still leaks, make sure you aren't sending rust and junk down the line.
    The pencil filter in the top of the tank valve is an important first step.
    If you have a cast iron sediment bulb,make sure it's spotless clean inside, or you may be sending junk down the line.
    I forgot to show the lock washer in picture 4.
    Don't overlook the final filter in the carb, as I've see rust collected there also.

    Here is a link to the main thread for addntl info
    https://www.vintagefordforum.com/for...rb-still-leaks

    Comment


  • #3
    Here are 3 pictures showing the 3 filters every Model A should have. The tank filter is an aftermarket item, but very important to keep junk from messing up the tank valve and carb. The second picture shows the cast iron sediment bulb, but many have the clear glass instead. I took these pictures of the cut away Model A that used to be at the Gilmore Model A museum in Hickory Corners, Michigan.

    Comment


    • #4
      Fuel LIne Install

      If the ferrule is seated to far onto the steel feed line this will restrict the fuel flow to the carburetor. Here is one sure fire way to get it right as the approx distance needs to be about a 1/16th.


      To set the ferrules for the gas line at the proper distance from the ends of the tubing, remove the filter screen on the carburetor. Obtain a 1/2-20 bolt about one inch long. Screw the bolt into the hole where the filter screen was. Put a nut and ferrule on the gas line, insert into the fuel inlet allowing the gas line to touch the bolt. Tighten the nut to seat the ferrule. Remove the gas line and swap ends to repeat the procedure. Using this procedure, the gas line enters the carburetor and the sediment bulb assy at a distance to allow full fuel flow.

      Note:
      It takes a lot of pressure to squeeze the ferrule and make it snap off the nut. Sometimes i score them a little more so they snap off easier.
      1~1931 Tudor ~ Dad
      2~1930 Tudor's ~ Lucy & Paul


      Henry Ford said
      "It's all nuts and bolts"


      Mitch's Auto Service ctr

      Comment


      • #5
        Here's my set up; the Wix filter/ gasket is available on line for a couple of bucks ( AC fuel bowl ). The glass bowl holds the gasket/ filter in place. I installed a coat hanger type wire connecting the (drip A gas valves.pdf insurance) ball valve handle thru a tiny hole in the fire wall for shut offs at outings.

        IMG_7285.PNG

        Comment


        • #6
          I ONLY ever use the "pencil" filter, the cast sediment bowl & the filter in the top of the Zenith! NEVER had any problems, even with some rust flakes in the tank!
          I would NEVER re-seal a tank!!!!---Like opening a can of WORMS!!!
          Bill Troublefree

          Comment


          • #7
            Mitch:

            Thank you for this thread.

            I will I’ll purchase some cork gaskets, and scour that fuel bowl.

            Thank You;

            Brian French

            Comment


            • Mitch
              Mitch commented
              Editing a comment
              Those bowl filters work great

          • #8
            Outstanding Post....thank you

            Comment


            • #9
              OK, I somehow missed all this the first time around. Excellent thread.
              1 question, 1 comment
              1) plyfor, how did you get the right angle brass fitting to seal in the shutoff valve on the firewall? That thread is machine, not NPT
              2) If you are using a die cast carb (Tilly), set your ferrules by inserting them into a cast Zenith, because to properly seat the ferrule, you need a fair bit of torque, and you don't want to stress the threads in the Tilly, they are soft

              Comment


              • #10
                Way overdone topic.

                I think it important that it is understood that the original A filters are very effective.

                For example, the fordor I owned had the rust settle into the valve problem. The car would start go a bit then stall. You blow back on the line and you were fine for a while.

                I took the valve off the tank and put a ball valve in place. Put some gas in the tank and shook the car hard. Then rapidly drained through a rag into a container. I repeated till the amount of junk was much much less.

                Then I put a short bit of 1/4 tube into the original valve before I put it back in the tank (this was not an indented firewall car) so the dirt settling could not clog the valve.

                I put everything together being sure the original filters were in good shape. They should not be crushed like in the cut away picture above.

                So now the crap in the tank was being caught by the sediment bowl. Over a period of time driving the amount of rust caught in the sediment bowl dropped off dramatically. Sadly, I decided to sell the car so I could build the cabriolet. I was getting to the point of removing the copper tube in the tank so I could use all the gas in the tank.

                You see the above method is not a band aid. It is the cure for the problem. I got the bad stuff out of the tank and did not have to need the filter screen the rest of the life of the car. I should also mention I monitored the carb bowl (I only use the original carbs). Never did I get anything in the bowl but nice clean gas. So you are really much better off making sure you have good original filters then adding something to the line.

                Comment


                • Mitch
                  Mitch commented
                  Editing a comment
                  Thanks for your real world information, that's what this site strives for. There are usually many ways to skin a cat, so having many proven options listed available is a good thing.

              • #11
                Sediment Bowl Screen Filter Info:

                When buying my 1930 Coupe in 1958 for $25.00, the very kind former owner and neighbor showed me why to never omit the sediment bowl screen filter ...... he removed the screen filter, placed water on it, and even minute drops of water would not pass through the tiny holes in this screen filter.

                Next he showed me that when water could not pass through the sediment bowl screen filter, water from the gas tank was noticeably encapsulated at the bottom of the glass sediment bowl, with gasoline floating on top whereby accumulated gas tank condensate water could not get to the carburetor.

                I soon realized that this vintage mechanic was really an analytical genius.

                Comment


                • #12
                  I only scanned it briefly due to time constraints however there is good content in there from what I saw. A couple of points. I read where it was mentioned that a tank should never be sealed. Most do not think of it this way but originally the tanked was sealed at the factory, ...and why folks believe it should not be sealed now is a mystery to me. As the original tank sealer erodes away, modern oxygenated fuels create the perfect catalyst for bare metal to begin rusting however re-sealing the tank in some method is much better than doing nothing from my view.

                  Ironically, most complain about the older sealers being an issue, but that really is not what I have found. While modern fuels can soften the older sealers, these sealers generally stay attached to the metal creating a barrier. The biggest issue I have found when opening up tanks is the previous tanks were not thoroughly cleaned prior to installing a sealer, AND/OR the tanks were never completely sealed inside with that sealer, --so it started pealing back allowing air to get under the sealer which allows the rust to continue. I read where guys fill their tanks up with a rust dissolver like Phosphoric Acid, Evapo-Rust or Rust911 to soak away the rust. Based on tanks we have seen this done on, it seems to do a fair job of addressing the rust however in many instances the rust is still loosely attached or trapped behind the baffles. Then when the modern sealer is applied, it does not get good adhesion to the tank metal and sooner or later it flakes off plugging filters and allowing rust to form again.

                  In my view, the ONLY way to address this is you must remove the original Terne sealer by media-blasting the tank metal until it is clean, then treat the metal with an acid to neutralize the rust down in the pores, then clean & remove the acid really well, and then completely fill the tank with sealer to ensure all areas are completely coated. Most people try to use one quart of product to fill an 11 gallon tank, and common sense tells you what will happen. With tank sealer over $100 a gallon, buying 11 gallons of product (to completely fill the tank) that has a short shelf life is out of most people's budget too. Therefore folks seemingly throw caution into the wind as they put themselves and their vehicle in danger almost every time they go driving risking breaking down on busy roadways. Then factor in the stress caused by a dirty tank and soon the vehicle becomes 'garage art' not to be driven. That is why I think so many 'restored' Model-As are street rodded, simply because the 'restored' Model-A won't Start, Stop. or Steer reliably, and as such Model-As have a bad reputation in the community.


                  gastank.jpg

                  Comment


                  • #13
                    Would love to know Brent's preferred brand of sealer, especially since ethanol seems to eat thru anything

                    I too have wondered how a 1 QT can is supposed to treat the entire inside of a tank

                    I guess since he does a bunch of tanks as a group, it is cost effective to buy 100 gallons and treat them all at once

                    Comment


                    • #14
                      Originally posted by tbirdtbird View Post
                      Would love to know Brent's preferred brand of sealer, especially since ethanol seems to eat thru anything

                      I too have wondered how a 1 QT can is supposed to treat the entire inside of a tank

                      I guess since he does a bunch of tanks as a group, it is cost effective to buy 100 gallons and treat them all at once

                      Right now I am using the improved POR sealer. It is nothing trick, the durability of the sealer comes from the interior prep.

                      Actually, ethanol really does not eat thru the sealer. From what I have seen, the issue that causes the breakdown is as fuel is sloshing and the tank is flexing, it begins to delaminate from poorly prepared surfaces. Once it moves some, it will rupture much like a skin blister on your hand, and then the ethanol works its' way under the edges and it just continues to delaminate the sealer from the tank metal. Only when the Terne finish is removed along with all of the rust will the surface be clean. Then using a coarser grit media it provides a 'tooth' for the sealer to latch on to. The Terne finish is slick so the sealer cannot grip onto it well, -and loose rust & sediment provides no grip either. There is not any way that I know of to remove all of the issues without opening the tank up. Even when those "ReNu" places do it, they are drilling holes in the bottom and back to access the inside with a sandblasting nozzle. Any of those companies that tells you they were able to get a tank perfectly clean are misleading you simply because there is no way they can access all sides of the baffles. They are cleaning what they can see and then filling the tank with a thick coating. You will always be able to tell a tank that has been repaired by them. If you cut open a tank like we do, the repair is virtually undetectable. Almost every fine-point car I have entered in MARC/MAFCA meets has had the tank cut open, and I have yet to have someone deduct for it simply because they cannot tell.


                      Below is a typical tank that is cleaned and then sealed by a hobbyist. Notice what happens to the sealer when it is applied over dirty metal. Also notice how well that quart of sealer covered the tank. The last picture shows the tank welded back together. If it weren't for the heat discoloration of the metal, I doubt you would ever know.





                      .

                      Comment


                      • Tony Hillyard
                        Tony Hillyard commented
                        Editing a comment
                        Brent, is it possible please to see the pictures again? They don't appear on your post. Thanks, Tony

                    • #15
                      Wowza, that looks great! it also looks like a helluva lot of work, but clearly worth it

                      and you obviously have it down to a science since you have clearly avoided distortion. Must be using TIG, in order to seal a tank seam

                      Comment


                      • #16
                        Wanna get rich? Invent a GOOD fiberglass tank that is dead on to an original..
                        ____________________
                        Good enough.. Isn't.

                        Comment


                        • plyfor
                          plyfor commented
                          Editing a comment
                          good point; we just pulled a '22 Lincoln rusted gas tank that had a complicated baffle system inside. No way to clean, etc. so our vendor cut out the top (hidden under car rear) removed the baffles, welded back the sheetmetal and $800 later, clean gas!

                      • #17
                        Mitch Great bit of information and the pictures and information was a big help thank you

                        Comment


                        • #18


                          Glass Bowl 101:

                          A. After proper glass bowl installation, this glass sediment bowl was designed to have the top of the glass bowl in contact with the bottom of a proper fitting upper glass bowl gasket; either cork or even better as advertised neoprene ...... and most importantly with gaskets as offered "only" by a reputable Model A parts supplier like Bratton's or several others.

                          B. Next the top of this same proper glass bowl gasket has to be in contact with the upper metal; i.e., solid top of glass surface to bottom of soft gasket, and solid top metal to top of soft gasket ............ not much different from millions of soft leak proof gaskets used Worldwide.

                          C. In carefully reviewing a proper Model A glass bowl when held upright, this bowl has an upper-inner recess which is designed to receive the metal filter screen.

                          D. If a new, poorly made screen is too large in diameter to neatly fit in this recess, this screen has to be carefully trimmed to fit down in this glass bowl recess; otherwise, the joining of this joint between the glass sediment bowl and the screen will leak through the openings in the screen.

                          E. A major problem is that some first place the gasket on top of the glass bowl, next place the metal filter screen on top of the gasket, and install this assembly with the screen in contact with the metal surface above, which is also guaranteed to leak.

                          F. After trying to understand these instructions, if one has a glass bowl that still leaks, try getting one of those Teeter-Totter Pain Relief Spinal Back Extenders Contraptions, rotate your body upside down, and try to assembling your glass sediment bowl while resting upside down.

                          Hope this helps.

                          Comment


                          • #19
                            Electric fuel shutoff maintenance

                            You might want to open up (remove the plunger) in your fuel shut off solenoid and clean the insides good with spray carb cleaner. I have to do this a couple of times a year because of the gas, even though I use MMO generously and Stabil or SeaFoam. You want to hear a "solid" click when you turn the key on. If it doesn't fully open you'll get fuel starvation symptoms.
                            Paul in CT

                            Comment


                            • #20
                              Additional fuel filter info!

                              Here is a little more info regarding the Wix 33039 glass bowl filter. The filter sits on the depression as pictured here. This is what holds the filter in place..

                              6213F79C-BED2-43E6-AE97-8D5D513F4EC5.jpeg
                              1~1931 Tudor ~ Dad
                              2~1930 Tudor's ~ Lucy & Paul


                              Henry Ford said
                              "It's all nuts and bolts"


                              Mitch's Auto Service ctr

                              Comment


                              • #21
                                sediment1.pngsediment2.png
                                1~1931 Tudor ~ Dad
                                2~1930 Tudor's ~ Lucy & Paul


                                Henry Ford said
                                "It's all nuts and bolts"


                                Mitch's Auto Service ctr

                                Comment


                                • #22
                                  Nov 2018 Newsletter

                                  D02389E3-CC39-4C5E-A640-CE47BE277A3A.jpeg105DCE7D-A72B-44EF-BC4B-C3EF01302727.jpeg
                                  1~1931 Tudor ~ Dad
                                  2~1930 Tudor's ~ Lucy & Paul


                                  Henry Ford said
                                  "It's all nuts and bolts"


                                  Mitch's Auto Service ctr

                                  Comment

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