MTFCA Forum

The cork gasket from the vendors leaks too much. It is destroying the paint on my tank.
If there is a neoprene one out there I am willing to try it.

Dave,

Would a properly sized neoprene o-ring do the trick for you?

Dave, I don't know if it would work, but have you thought about sealing the cork gasket with silicone gasket sealer on both sides and letting it dry before use. Maybe if the silicone was spread thinly and evenly with a putty knife over both sides (one side at a time) and allowed to dry thoroughly, maybe that might do the trick.

I thought silicone was not to be used for gasoline? If anything was used aviation fuel lube works well for me.

Jerry, I have tried an o ring and I am not impressed. I do not think there is enough surface area with an o-ring to seal well. One person suggested an x section o ring. Might work.

Terry, that sounds like a good idea. Wonder what kind of silicone is the best for fuel?

Pat, this is for the gas cap, not a shut off valve.

Internet says to try this:


Oil-Resistant Aramid/Buna-N Gasket Material
Made from a blend of aramid fiber and Buna-N rubber, these sheets and discs resist oil, water, and aliphatic hydrocarbons such as ethylene. Cut with a gasket cutter. $1.50 ....


McMaster Carr

Maybe don’t fill it as full?
The caps all have a vent hole also.
Are the baffles still in tank?

Dan Hatch wrote: ↑

Mon Oct 07, 2024 10:42 am

Maybe don’t fill it as full?
The caps all have a vent hole also.
Are the baffles still in tank?

Agree. Make sure you cap and tank threads are good so the cap tightens on the cork gasket

As for wrecking paint, gasoline does that, T gas tanks were never painted.

I brought a Langs gas cap gasket for 35 cents and it works fine. If you needed to paint it due to rusted plating you can use Caswell epoxy tank sealer on the outside also. I did a tank over inside and outside with it in black. It came out great. Ive used rustoleum on a dozen bike tanks and it held up for years, even with occaisional spills on them. Trick is to the paint set up for a month or more.

For anyone with a Torpedo with the larger cap and possibly others I found the rubber gaskets from an oil filter canister works perfect and the gas does effect it!

Pat Branigan Wisc wrote: ↑

Sun Oct 06, 2024 6:48 pm

I thought silicone was not to be used for gasoline? If anything was used aviation fuel lube works well for me.

Pat, you may be right about silicone and gasoline. I'd never tried what I suggested and didn't think of that. Maybe sealing the cork with gas tank sealer would be a better option.

DanTreace wrote: ↑

Mon Oct 07, 2024 11:25 am

Dan Hatch wrote: ↑

Mon Oct 07, 2024 10:42 am

Maybe don’t fill it as full?
The caps all have a vent hole also.
Are the baffles still in tank?

Agree. Make sure you cap and tank threads are good so the cap tightens on the cork gasket

As for wrecking paint, gasoline does that, T gas tanks were never painted.

Dan, Under seat tanks were never painted but I've seen a few cowl mounted tanks that appeared to have original flat black paint on them.

But under cowl tanks have a splash tray at the fill hole with drain to ground.

Indian Head Gasket Shellac might make the cork seal gas-tight without making it too stiff to seal. At least some types of silicone gasket maker will soften and swell if exposed to gasoline. Some types of o-rings and oil filter gaskets will do the same. It may take a few days of exposure to see the effects.

It may be that the baffle is missing from the underside of the cap, and the fuel is actually being sloshed out of the vent hole.

Allan from down under.

Maybe a Thicker neoprene impregnated cork gasket? Also If the cork dries out too much from sitting try soaking it with light oil to make it swell