Black tar in gas tank

J

Jim_Chesapeake_VA

Junior Member
New to the Model A world. My wife I purchased a 1929 Tudor. I knew up front that I had work to do on the fuel system as they had one of those "burn your car down" plastic fuel filters and rubber hoses on the inside of the cab. Draining the gas tank today and removed the rubber/plastic fuel components and found thick black tar coming out the cutout valve and the plastic filter. There is rust in the tank as well. Looking for advice on first steps to take. We were debating cleaning the lead shot/mineral spirits, or taking to radiator shop to clean or sending off for restoration. Any ideas are appreciated.
 

Attachments

  • tar1.jpg
    tar1.jpg
    42.7 KB · Views: 114
  • tar2.jpg
    tar2.jpg
    42 KB · Views: 113
  • tar3.jpg
    tar3.jpg
    42.8 KB · Views: 121
Check the inside of that rubber hose, that may be where the "tar" is coming from.
What do you see inside the gas tank?
 
I've worked on equipment all my life,and that is the most common thing I saw.In the pre-ethanol days that stuff was what I found every week in tractors,crawlers,old cars,etc.Depending how hard it had gotten I would use laquer thinner,acetone,or MEK to liquify it.
 
The original system had no rubber hose or plastic parts. There were three different fuel valves used and none of them are like the OP's valve.

When fuel is left to set for long periods to evaporate. It leaves a varnish like goo behind. I don't envy a person that has the nasty job of cleaning out an old fuel tank. The model A type tanks are not easy to clean. I hope the corrosion in minimal. It's even harder to remove without cutting the top off.

I've used Drano or caustic soda to remove varnish but it won't remove corrosion.

The saving grace of the model A tank is that they were made with 16 gauge steel. It takes a long time for corrosion to eat through 1/16th inch of tern plated steel but eventually it will. I've seen holes a person can put their fist through in a few of them.
 
Last edited:
I put about 5 gallons of vinegar in a tank and wait 6 weeks. Have always done well
with it. if youre in a hurry, then more expensive evaporust.
 
Jim,
When we brought our '30 coupe home four years ago the gas was like goo in the tank. I put several gallons of lacquer thinner in the tank after hooking the compressor hose to the sediment bowl. With low volume I let it bubble and splash in there for several hours, drained and repeated again. Since we have had had no fuel related problems. Dale
 
Thank you for all your recommendations. Going to try POR15 De-greaser as a first attempt (found some information on this site about it). Seems like the most non-toxic/non-flammable way to attack it. I figure if that doesn't work I will move on to lacquer thinner. After that I will look at attacking the rust.
 
So things have escalated quickly. I used the POR degreaser and then I used Rust911 to work on the rust. After three days I drained it. It kept clogging, so I had to blow the line to clear. The Rust911 said you can keep reusing until it turns black. Well it came out black. Removed the tank from the car, noted a large amount of debris in the tank, using long screwdrivers, wood sticks and a bent flat bar to break up all the stuff between the baffles, tank looked pretty decent, I couldn't see much with my inspection camera behind the baffles. Next I tried lead shot and mineral spirits with lots of lifting, shaking and rotating. That's when the black tar chunks stated appearing again. Hosed out the tank again into three 5 gallon buckets,. And kept coming out dark. Inspection camera revealed a layer of black tar sediment behind the baffles. Going to try laquer thinner and soak it for a week to see if I can get it to dissolve.
 
Do you know if that car had been sitting unused for a long time? If so, who knows what some kids may have put in the gas tank.
I once bought a 1947 Mercury 1/2 ton that had been sitting in a back yard for a year or so. The gas cap was missing but I didn't think anything about it, just stuffed a rag in it 'till I got the proper gas cap. Started having trouble w/the gas line to the fuel pump plugging up, would blow it out, back to the tank, go a few miles and it would plug up again. I decided to remove the tank and clean it out. The tank was under the seat so it was fairly easy to remove. W/the tank out I started shaking it and could hear crud rattling around inside. Cleaning it out I got about a 1/2 a cupful of gravel, a 1" paint brush and a piece of rubber weathersripping about 1/2" X 3/4" and a foot long.

Good luck w/your cleanout.
 
I was able to break the shelf of solidified tar up behind the baffles using a bunch of nuts. Looks like all the big stuff is finally gone. My guess is that the car sat for many years based on the 1/4 to 1/2 layer of tar on the bottom. Moving on to laquer thinner now.
 
Hello,Kerosene may also work probably cheaper per gallon, also being a light oil won’t cause rusting. Before using a caustic type cleaner I would try as you have the rust dissolving solutions , had bad luck with drano , ate a hole in the tank but may have been thin before, this car had sat with gas cap off for some time, had dead mice and other debris too .If a quality repo gas tank were available probably have a good market, but I think because of legal concerns and complexity of manufacturing won’t happen.
 
pre ethanol tank sealer was shellac and not soluble in real gas, new gas will disolve it and make real mess in your engine. how do know this.
 
You must log in or register to reply here.
Back
Top