I have a stainless fuel tank that only has two holes in it, fuel inlet and outlet. This is fine as I'm running carbs but I need to add a breather to allow air in when the fuel is sucked out.

I have been told that I could drill a hole in the top of the fuel filler cap but it cost me a lot of money and I don't want to wreck it.

I've had an idea to drill a small hole in the rubber filler tube and push a check/one-way valve into it. If the hole was small enough to just let the valve through I think it might seal the hole around the valve. I would ideally like a valve that has a screw fit so I could put a nyloc on the end in the filler tube to stop it popping out. Trouble is I cant find one like this. I have looked at the think automotive site and the ones on there don't seem to be long enough to go through the tube and also have the nyloc securing it. I have made a very bad drawing in paint to give you and idea of what I am after.


breather

The screw threads need to be about 30mm long and the diameter about 12mm. The length is the most important so the nyloc can bite on the thread when it's through the hose. Anyone got any ideas where I could get one from?

All the other check valves I have seen use the ribbed design that are used in line and secured with jubilee clips. Using this type of valve could make it difficult to stop it falling out.

Do you think this way of doing it is a good idea? Are there any other options that you guys could recommend?

Rhod

I put my return line and breather on the same tank connection.

Main feed is the bottom exit on the tank.

Top return connection then goes to a tee which is connected to my one way breather and my fuel return.

No problems yet...

David

Has the carbs got a return pipe?
when you say fuel in & fuel out can you use the fuel in as a breather if the carbs dont have a return

No return pipe on the carbs that I know of. Only the filler neck and the fuel outlet.


Rhod

[Edited on 27/3/09 by rodders]

So you have a big filler pipe50mm and a fuel out small 8mm pipe?
Do you have a fuel gauge sender that you could drill and put a small pipe union though for a breather

[Edited on 27/3/09 by jacko]

I added a breather to the fuel sender top mounting plate .

Yep only those two connections. The copper pipe screws into the tank.

Rhod

Ahh, I misinterpreted your post...

You can get fitting which fit into the side of rubber hoses which you could just fit into your filler pipe?

Sorry another bad drawing. This is what I'm thinking of doing.


Description

Rhod

Do search...been discussed many times.
You need a valve that works in and out unless inverted.
Even a tank with no return pipe will expand in warm weather.

I have searched other posts but from what I have read the other tanks people have used have three connections on them and mine only has two.

Is it a good idea to do it the way I have suggested? Where would I get a two way valve with 30mm screw threads on at least one side?

Is there and easier way that I could get a breather to fit on the tank?

Rhod

[Edited on 27/3/09 by rodders]

Get a large repair washer 6mm hole
solder a 6mm pipe in it
then drill a 6mm hole in the tank top
put the washer /pipe over the hole and self tapper the washer to the tank put sealer in between the washer and tank


AS BELOW HAS THE TANK HAD FUEL IN THE TANK

[Edited on 27/3/09 by jacko]

drill a hole in the top fit a breather job done.

remove fuel first would be top tip of the day

fill tank completely and utterly with water & use a hand drill would be my top tips!

(fumes, drill bit, heat ........ bang)

I'm very nervous of the idea of drilling a tank that has had fuel in, but I've seen several suggestions:

Remove fuel first and repeatedly wash out or drain and fill it with water before drilling.

One other trick I have heard of is to drain, run an engine and pipe the exhaust into the tank or using a welding bottle to create an inert atmosphere. The engine option would presumably need a load of wire wool or similar in the pipe to avoid an ignition source.

Possibly just draining and leaving open for an extended period would do.

I'm not sure of the efficacy of any of these, so just in case I ever need to do it, would someone please advise...

I have never put any fuel in the tank so I don't need to worry about an explosion, it was also new when bought it. I would prefer to use a proper breather just in case I roll the car when it's eventually finished.

Drilling and fitting the breather to the top of the tank is probably the easiest option but it might be difficult for me to fit. I cant get my hands into it because the sender hole is to small or my hands are to big.

Anyone used the TRV45 at the following link?

http://www.thinkauto.com/tbvcolour.htm

I think this is the one I will be going for as there is not much room between the top of the tank and the boot floor.

Rhod

I drilled 2 x 3mm holes in the fuel cap under the pull out handle!

I've seen some self sealing connectors somewhere that would fit into the filler hose as already suggested . Possibly Demon Tweeks? or CBS? would at least save having to drill into the tank.

Remove filler neck (the bit that the cap fits onto), drill hole, solder (if possible) or weld in small bore pipe to filler neck, refit neck, fit breather pipe, refit cap.

JD.

Burton power sell the self sealing hose takeoffs

https://www.burtonpower.com/product_main.aspx?dets_product.aspx?PSet=97&sTxt=self%20sealing%20hose

David

Are you sure you don't have a vented filler cap?
Could you change it for one?

Just checked the cap and its not breathable. Thanks to rusty nuts and flack monkey for pointing out and finding the self sealing hose takeoffs for me. There exactly what I'm looking for.

Rhod