New gas valve replacement...

[RRW]

Should I use Yellow PTFE gas line thread seal tape or just hand tighten as Paul Shinn does on his fuel line 'replacement' video.
I am installing an A-09189-a valve and an A-09194 filter.
Present valve has lasted 30+ years with no tape.
Sammy at AZ Model A says the crappy gas with excess ethanol is causing many problems with our A's. And is only getting worse.

[alexiskai]

No tape should be needed. If it leaks, liquid sealant should be adequate to seal. BTW, yellow tape is for gas as in natural gas, not gas as in gasoline.

[RRW]

Alexiskal,
Thanks for the yellow tape info.
I guess that's why AutoZone and O'Reilly's didn't have it but Ace Hardware did.

[stickshift]

My '31 valve connects directly to the firewall with a NPT fitting into the tank. Pipe thread fittings should have some type of sealant (tape or dope). Flare or ferrule fittings, nothing.
My valve is original and had a slow drip when shut off. I heard that the newer valves are cheap, so I took apart my valve and used some rubbing compound with the valve stem in a drill and me holding the valve body. I worked in the compound (some people use toothpaste) with the drill spinning the tapered valve. I did this for about 5 minutes until parts were polished. I bought a valve rebuild kit for $5 available at most model A parts vendors and reinstalled. No leaks!

[Dick M]

NAPA carries a thread sealant that is made to use with gasoline. I used it the last time I changed the shutoff valve and no leaks...

[oldspert]

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Originally Posted by RRW

Sammy at AZ Model A says the crappy gas with excess ethanol is causing many problems with our A's. And is only getting worse.

Same here, my shut off valve under the tank will not shut off the fuel to the carb. I know it is from the ethanol eating up the seal in the valve. I can put 1/2 gallon and it leaks past over night. I am going to add an electric shutoff but my car is still 6 volts. I need to run the shutoff through a relay to keep from going through the switch, if I can find a 6 volt relay.

[Y-Blockhead]

Originally Posted by oldspert

Same here, my shut off valve under the tank will not shut off the fuel to the carb. I know it is from the ethanol eating up the seal in the valve. I can put 1/2 gallon and it leaks past over night. I am going to add an electric shutoff but my car is still 6 volts. I need to run the shutoff through a relay to keep from going through the switch, if I can find a 6 volt relay.

What seal? The valve is brass on brass. Are you suggesting the ethanol is eating the brass? I don't have an answer for that.

I do know the repro shut-off valves don't seem to last very long before starting to weep. Seems I have had to replace mine every couple of years. Maybe add some MMO to lubricate it?

[Phil Brown]

Originally Posted by oldspert

Same here, my shut off valve under the tank will not shut off the fuel to the carb. I know it is from the ethanol eating up the seal in the valve.

Most likely ethanol causing the problems, I've seen a lot of sand cars and race cars try and run E-85 on carburated motors. Yes, more ethanol to gas in that fuel but still ethanol brass jets, and other parts just get attacked and destroyed over time. Not a good combination
Try it yourself, put some ethanol in a jar on your workbench and throw in an old brass carb jet or other part for a few weeks and see what happens

[WHN]

Originally Posted by Phil Brown

Most likely ethanol causing the problems, I've seen a lot of sand cars and race cars try and run E-85 on carburated motors. Yes, more ethanol to gas in that fuel but still ethanol brass jets, and other parts just get attacked and destroyed over time. Not a good combination
Try it yourself, put some ethanol in a jar on your workbench and throw in an old brass carb jet or other part for a few weeks and see what happens

Another reason to be using MMO in your cars gas?

Haze Gray and Underway.

[Phil Brown]

Originally Posted by WHN

Another reason to be using MMO in your cars gas?

Haze Gray and Underway.

MMO will not stop the ethanol from attacking the brass, you need to remove the ethanol from the gas

[Y-Blockhead]

Originally Posted by Phil Brown

MMO will not stop the ethanol from attacking the brass, you need to remove the ethanol from the gas

I'm still not 100% convinced it was totally the fault of the ethanol that my valves leaked but I got tired of replacing the S/O valve so I added a second valve, no brass, no issues.

[nkaminar]

I personally use Teflon tape to seal pipe threads. The danger is getting pieces of the tape into the gas line and causing problems down stream. I have also used Permantex #2, which is not effected by gasoline, even the modern gasoline. I have used the yellow tape in gas lines and to seal spark plugs in my Model T, which is a pipe thread. I think the yellow stuff is thicker and yellow to identify gas lines to the next plumber in a house. Otherwise I think it is the same as any other Teflon tape for sealing.

To keep petcocks working well and sealing, use EZ-Turn. https://www.aircraftspruce.com/catal...ezturnlube.php

[oldspert]

Maybe I'm a dumb A$$ but what is MMO?

[Jemelton#]

See thread

https://www.fordbarn.com/forum/showthread.php?t=325749

[devoreb]

The best thread sealer for gasoline is rectoseal. Its available at any hardware store/ home center. It will not disappoint.

[WHN]

Originally Posted by oldspert

Maybe I'm a dumb A$$ but what is MMO?

Marvel Mystery Oil.

There are reports that it will help offset the effects of ethanol in todays gas.

It is used by some to help lubricate your valve system.

Some call it snake oil. I have used it in our antique cars for years.

Enjoy.

[David in San Antonio]

Originally, snake oil was revered as a good all-purpose medicine and tonic. The negative connotation came with crooks who would brew their own highly alcoholic mixtures that were found to not contain any genuine snake oil at all!

[DaveBPT]

I just replaced a shut off valve yesterday that had been on the car for 2 years and not had 5 gallons of gas through it. Took it apart to find an "O" ring was the sealing method. Not well built. Started using 100% gasoline in all my old cars. Noticed with first tank that the cars ran smoother. Don't have to worry about alcohol separating from ethanol gas.

[stickshift]

I heard the newer valves used an O ring instead of the graphite packing as the old valves had. That's why I opted to just put a "kit" on my original valve. Comes with packing, new nut, lock washer, and special lube for the valve moving parts. Under five bucks at most supply houses. This picture was from Bert's, $3.75

[Synchro909]

Originally Posted by stickshift

I heard the newer valves used an O ring instead of the graphite packing as the old valves had. That's why I opted to just put a "kit" on my original valve. Comes with packing, new nut, lock washer, and special lube for the valve moving parts. Under five bucks at most supply houses. This picture was from Bert's, $3.75

I've used that kit - works well. For a driver car like mine, I recommend using a 1/4" ball valve, Fixed for life.