Technical Question For Ford Model A Based Builders: Are You Using The Fuel Shut-Off Valve?

Thanks for taking a look at my post.

I'm working on an alternative 1/4-turn shut-off valve for Ford Model A gas tanks. One that's ethanol/gasoline proof, and performs without leaks for many thousands of open/close cycles. It would not be an exact visual match to the original, but it would look "period correct".

I have an unrestored stock Model A, but I need more insight on how people are using a fuel tank shut-off valve in custom builds.

These are my questions:

If you're using gravity feed to the carburetor, are you using the repop valves sold by the Model A suppliers? If not those valves, which valve are you using?

Maybe you're using a fuel pump, but still using the original gas tank. Are you using a fuel tank shut-off valve? What type of valve...the repops, or something else maybe?

Are you using the stock fuel tube (shut off valve - to - strainer on the firewall)?
Are you using the stock fuel strainer?

Many thanks for your help everyone!
Alex

 

My pops is using a stock shut off on his Av8

 

if you have the early/normal model A fire wall, i like the stock valve. the later stupid indented fire wall with the valve under the hood sucks. in that case, i route a new line to put a valve in the cabin where it belongs. keep in mind, with a gravity fuel supply you MUST turn off the gas when you park it in the garage. even if you have never seen it leak...some day it will. the ford valve inside the cabin sometimes weeps enough to get gas smell on your hand, so i assume thats why henry changed it. i have never had a leak bad enough it cant be fixed. yellow time saver is a product made for seating soft metals. its like valve lapping compound, but its abrasive quality's break down so it becomes neutral, and does not continue to eat metal. also used for finish fit of Babbitt bearings. next, you need to have an aircraft friend, and get some of the special grease they put on gas valves to seal them. its like Vaseline, but does not wash away with gas, and makes it easy to turn the valve. very expensive stuff, you need a little dab from a friend, not a 75 dollar jar you will never use.

 

My late '31 Coupe with B 4 banger is stock under the hood pain in the butt. My '31 Roadster pickup with stock engine is a stock reproduction valve from Snyders, inside the cab. Never leaked. My avatar '29 Sedan with 59A uses stock tank and I put a new ball valve w/lever from local hardware store. Better than stock.

Dave

 

Reproduction stock shut off valve on the ones with tanks still in the cowl.
The reason they leak in the first place is that they are a plug valve...two bronze surfaces turning against one another to form the seal. All it takes is a flake of rust to score the mating surfaces and you have a valve that will have post nasal drip.
Drain the tank and pull the old one. Flush the tank really good and see what comes out.
Inspect it internally to get an idea of condition of the tank surfaces. If it isn't too bad, I've had real good luck just keeping the tank topped off so as not to form condensation in the tank.

 

When I had my 31 with the indented firewall I installed the electric sol shutoff. No more opening the hood. I believe on the re-pops they recommend dis-assembling and lapping with toothpaste.
Paul in CT

 

I used a stock shut off on my avatar which was a V8 A and on all three banger powered A's I've had with no problems. The stock shut offs I've rebuilt were a metal to metal seal with a graphite seal on the stem. Just used a little valve lapping compound on the seat and they are good to go.

 

Since automotive fuel contains ethanol, and AvGas does not, is this grease still working well and leak-free in your valve? Thanks

 

Do you know which materials your valve is made from? Basically, are those materials gasoline and ethanol 'proof' over a period of time? How long have you been using this valve, and is it still leak-free? Thanks

 

I have also found this to be true with several original and repop valves that I took apart. I also had repop valves that tore themselves apart within months due to brass shavings inside. These valves also had the aftermarket 'pencil' type screen installed from day one. I'm thinking its a quality issue with the repop valves.

 

I haven't seen instructions like that. Was that on some written instructions with the repop valves, or did someone recommend doing that process? Thanks

 

If you wish to use an aftermarket valve, look for a Swagelok / Whitey stainless quarter turn one on the auction site. They are extremely well made and unlikely to leak, ever. They also have nice handles.
They are typically rated for thousands of PSI working pressure, which of course is moot in this case.

 

In my A I used a quarter turn Ball valve from the hardware store. It is all metal parts. Nothing for the ethanol fuel to attack. Had it for twenty years. No problem.

 

I think like @pprather said it is all metal. Been using it for going on 4 years. Never a leak and works super smooth.

Dave

 

The toothpaste was a "tip" on either FordBarn or the VFF if I remember correctly.
Paul in CT

 

I've had a quarter-turn valve in the sedan to your left for 30+ years. The sedan has a carbureted 231 Buick V-6 and, I guess, I didn't turn the valve off one time years ago. The carbonator couldn't hold back the minuscule gravity fuel pressure and deposited a bunch of gas in the pan. I started it up and the oil pressure was low (duh!). Checked the dip stick and it was real clean. Drained it all out and try to not let that happen again. Ten or so years later, no side effects yet.

 

Many thanks for your help everyone.

The best I can figure is that, if you have a Model A based build, most people tend to keep using the original type cowl gas tank, and they're using a fuel shut-off valve also.

As I said in my first post, I'm working on an alternative 1/4-turn shut-off valve for Ford Model A gas tanks. Thanks to your input, I now have a better insight into how the gas tank and shut-off valve are used in non-stock applications. It's my hope that as I finish this valve development, it will be well suited to most types of Model A applications...from custom to stock.

Alex

 

My 29A roadster pickup has a stock shut off valve w/o the glass bowl...instead on the firewall side there is a 90 degree fitting and rubber gas line to the mech. fuel pump. Been on there several years and so far so good!

 

This is a common marine valve. Get a 3-way and you can plumb a convenient drain while you're at it.