Fuel line size ?

R

racer32

Senior Member
Working on a late '31 with a Tillotson (if it matters). My fuel lines are a cobbled-together mess of mismatched pipe, AN, and brass fittings (former owner was an airplane guy). I plan to straighten out the mess, but in the meantime I have a few questions:

Will 1/4" tube be adequate to run the car at speed? If not, will it work for stationary testing?

Will an aftermarket fuel bowl that has 1/8" pipe threads in and out restrict fuel flow?

What size fittings work in the fuel shut-off and carb?
 
The repro fuel line I bought from one of the suppliers is 1/4" OD. I expect it would work fine (haven't used mine yet). Sorry, can't help wit the other measurements, off hand.

Steve
 
1/4" steel line as the others have said. Available at any local parts place. You'll need about 2.5' but buy 3' so you have some extra. DON'T use copper unless you have a good fire extiguisher.
 
What about the carb and fuel outlet?? NOTHING at the hardware store seems to fit those threads. are they 5/16 flare?
 
The thread is 1/2 X 20 tpi it is a special fitting you can get from any model A parts supplier. You can also order the correct fuel lines. JMO.
 
The fuel line should not be flaired. The fitting threads are 1/2 X 20 . Ferrules are used with the fittings as Tiny says above.
 
Purdy Swoft said:
The fuel line should not be flaired. The fitting threads are 1/2 X 20 . Ferrules are used with the fittings as Tiny says above.
Click to expand...

OK, so the fuel lines themselves use compression fittings, then? Were the lines originally 5/16"? 5/16" compression fittings have 1/2" x 20tpi straight threads. I'm REALLY concerned about squeezing a brass ferrule inside that potmetal Tillotson!!! There was a steel flare to 1/8" pipe nipple in the carb end of the mess that was in there when I got the car.

FWIW, thread size for 5/16" flare is 1/2"x 20tpi, too...might explain prior owner's use of flared male to 1/8" pipe adapter in the fuel shut-off

Snyder's has a kit for late 31's without side-bowl carb...I know that should work, but I don't like the glass bowl hangs from the lines in their illustration. I also can't drive to their store and look at it before I buy.
 
Last edited:
The same fuel line and fittings fit both Tillotson, Zenith and all of the other upodraft carbs made for the model A that I know of. The same fittings and ferrules also work with glass bowl sediment bowl , cast iron sediment bulb and the cast side bowl used with the 1931 models. I've used steel brake lines from local parts houses as well as copper tubing with never a problem. Problems with copper tubing is highly over rated.
 
You must log in or register to reply here.
Back
Top