Petrol fumes.

[lotuselanman]

Gidday,
Petrol fumesin the cabin and boot, how does one eliminate this annoying problem ?
Les.

[alaric]

Apart from the obvious of checking for leaks, the fuel tank breather hoses may have perished. Check where they exit under the rear wheel arches - if one of them is no longer poking out of the grommet, it'll be venting into the car. Apart from those two pipes, there's a gasket around the fuel sender unit that'll make a pong inside the car.

Good luck.

Sean.

[1964 S1]

Greetings, possible solutions have been described on a lot of previous threads here.
I suggest keywords "fuel smell +2 vents" or something like that. There are several things on a +2 that can create your problem. Tank venting seems to be the culprit frequently and the remedies vary.

[Jason1]

Hi

I have an early +2 and the vent pipes just poke through the wheelarch and hang there, so I do get a lot of smells.

I have just replaced the cap seal and this really cut down the smells. I got the seal after much searching from SJ sportscars I think it was about ?2.

give them a call.

Jason

[ppnelan]

The vent pipes are the worst cuprit, but I recently discovered that there are actually 2 seals on the fuel cap. One is the big 'washer' that seals the top of the filler pipe. The other is a small rubber 'tube' that sits behind the other one & it's sprung plate, in the middle of the cap inside the spring. This one seals the sprung plate to the cap. Take the cap apart & you'll see what I mean. If either one isn't working, you'll not only get a smell (outside) but the common overflow of fuel down the rear wing around righthand bends...

Matthew

[lotuselanman]

Interesting, Thanks.
Les.

[carrierdave]

Hi All,
I am looking to replace my petrol tank vent pipes. The original ones have lost all of there flexibility and would probably crack if I attempted to change there shape.

Can anyone suggest a supplier for this pipe or confirm the diameter?

Thanks

Dave

[Robbie693]

Paul Matty lists Breather hose at ?1.75 (per metre presumably)..

I was thinking of getting them to replace mine as I don't fancy trying to remove the rear screen - any ideas how much they'd charge?

[mikealdren]

Dave,
Spyder (Andy) told me that the pipes start off flexible but harden rapidly (possibly due to the effects of petrol fumes?). They are then difficult to remove. He sees this as standard and it helps the pipes hold their position over the back of the screen. It may be a red herring but you may not need to change the hoses.

The Spyder solution takes the output from the vents to a 'T' piece in the fuel filler. This is fine for putting any excess fuel and fumes back into the tank but doesn't vent for any pressure variations. The fuel cap has to leak to accommodate pressure changes.

For my rebuild, I'm planning to put in standard pipes to the top point where they will join at 'T' piece with a small diameter vent pipe leading to one wheel arch. That should allow the system to breathe while limiting the fumes. Not my idea but it seems a good solution.

I'm very open to other ideas.

Mike

[gordonlund]

A standard +2 petrol tank requires large diameter breathers to enable filling of the tank beyond half capacity. This is because the filler pipe feeds into the tank half way down. If you only have small bore breathing capacity it will enable the tank to breath for normal running, (if you have a breathing filler cap) but will take ages to fill the tank beyound half full. Piping the breather into the filler kneck will not enable the tank to breath under normal running. The standard filler cap is fully sealed and 2 psi suction on a petrol tank is enough to collapse the tank.

Standard 1/2" bore polyhene pipe is all you need from any plastics suppliers. Make sure the two pipes run over the roof lining and exit out the inner sills through new close fitting well sealed grommits otherwise the fumes will get back into the car. This requires removal of the rear screen and carefully peeling back the roof lining.

Gordon

[carrierdave]

Thanks to all. The replies were, as always, very helpful. I was also wondering if anyone had looked into the modification shown within the owner?s manual where they fit carbon canister filters?

Has anyone ever done this or come across a car that had it fitted? Are they still available and did it work?

I know ultimately there would be a usable life for the filter as at some point the carbon would become saturated. I have looked on the web but have been unable to find a suitable supplier - anyone else looked into this?

Any thoughts

David

[mikealdren]

Dave,
I'll look at the manual tomorrow, I don't remember anything about carbon filters. However I am dubious about whether they would deal with the volume of fuel involved.

My reply to Gordon also seems to have gone astray (with my memory?) Gordon is absolutely right with his comments but unfortunately, the result of the standard half inch hoses is a a garage that stinks of petrol and I am still after a solution and I know a lot of other owners are too.

We need a way of venting the tank to allow filling while preventing fuel/vapuor escaping in large quanitites. Has anyone got a solution?

Mike

[rdssdi]

The charcoal canisters are part of a vapor recovery system as now mandated and in all cars. The tank vents through the canister which absorbs the fuel vapor and when it is saturated it returns the vapor to the carb to be burned.

I had a new alloy tank made by Axminster Specialist panels. As I specified, the tank height was lowerd to make room for two Mocal breather vents. The vents are supposed to close to the atmosphere between a pre-set negative and positive pressure. What that is I do not know. In addition they will prevent fuel from exiting in the event of a turn over, full tank or "sloshing" fuel in turns.

I have attached a photo of the installed tank. I have a few gallons in the tank and have run the engine. The car is in a large shop and there is no smell of gasoline. Either the vents work or the volume of air in the shop disperse any fumes.

Bob

[mikealdren]

Bob,
Looks like you have a neat solution, can you give a few details please?

Do the Mocal valves vent into the boot or do you have a pipe leading out somewhere?

Does the tank still fill reasonably quickly?

Did you think about putting the valve on the standard outlet (where the pipe goes vertical). I'm would rather retain the original tank.

thanks
Mike

[ppnelan]

Those look like serious earth straps

Matthew