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, 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 3039 and the WIX number is 33039 or you can cross-reference these to your favorite brand. 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, and place the screen in the depression of the glass bowl above the filter. (below the gasket) 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 hazard 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 3039 sediment filter
13280_2_1.jpg14260_2_1.jpg33039.jpg
image_757.jpg
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, 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 3039 and the WIX number is 33039 or you can cross-reference these to your favorite brand. 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, and place the screen in the depression of the glass bowl above the filter. (below the gasket) 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 hazard 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 3039 sediment filter
13280_2_1.jpg14260_2_1.jpg33039.jpg
image_757.jpg
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