Fuel tank breather

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Vintage man
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Fuel tank breather

Post by Vintage man » Mon Mar 26, 2018 4:52 pm

Hi ,the fuel tank breather,is it ok to let the fumes out the bottom or must i make a plan to the air cleaner as the single carb with a pancake filter has not got any fitting for it.It was a 2L but now a 1600 engine in.

What material can I use in the engine lid ,top lid in the bus as the fibre? that was in there is shot.
Thanks in advance.



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fig
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Re: Fuel tank breather

Post by fig » Tue Mar 27, 2018 4:30 pm

Most urban smog is caused by unburned hyrdocarbons, including evaporated fuel. In most first world countries and on all more modern cars, the fuel tank vents through an activated carbon filter to prevent escaping into the atmosphere. I'm not entirely sure that venting the tank to the carb inlet is a good idea because it may be a fire hazard. AFAIK, on SA baywindow buses the fuel tank vents into the atmosphere somewhere up one of the rear corners.
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Tony Z
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Re: Fuel tank breather

Post by Tony Z » Tue Mar 27, 2018 4:40 pm

Yip, they vent to atmosphere but go through carbon filters first. You can see them in the engine intake ducting on the body above the engine.

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Re: Fuel tank breather

Post by retrovan » Tue Mar 27, 2018 4:57 pm

Me thinks he is mistaken with the oil breather that goes to the carb, I have a pancake paper filter on my fastback, and I fitted a pipe fitting into the base of the filter housing to connect the oil breather, but please do not run your fuel tank breather into the carb, it will turn your ride into a nice bomb.

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Re: Fuel tank breather

Post by Vintage man » Wed Mar 28, 2018 7:19 am

Hi Fig,Tony and Herman

Its the breather pipes that come from the tank that used to fit to the air cleaner on the 2l.They are the steel pipes with the 6mm rubber fuel hose that joins them.At the rear of the engine bay the two steel pipes are on the top of the engine bay.The steel pipes are from the tank around the sides

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Re: Fuel tank breather

Post by retrovan » Wed Mar 28, 2018 8:59 am

These are the fuel vent system, but do not join to the carb, but to each other.
The vent comes from two points on the fuel tank, cross over to the opposite side, go up the air vent area, come down and then join in the engine compartment roof near the inside of the number plate. It should be a rubber tube that slips over both pipe ends.

On my bus these joints, and there are 8 or 9 of them, and they all started leaking as they did not have clamps on them and the pipe got hard and loose.

My recommendation is that you take the motor out, remove the fire wall, and remove the tank and inspect ALL the rubber fittings, as they split and leak when you least expect it.

What ever you do do not connect it to the carb.

Image

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Re: Fuel tank breather

Post by Tony Z » Wed Mar 28, 2018 11:50 am

in stock format, they do actually run into the filter like Vintage Man has said. But that is after having passed through the carbon filters.
It doesnt have to go into the filter, but if it does, it is a bit better for the environment.
Beetles of the same era run the vent to atmosphere. I run my bus's vent to atmosphere.
I cant remember exactly where in the filter it goes, but I'd run it to the atmosphere side of the filter element to reduce the low vacuum on it and thus avoid pulling out of the tank. Plus, if you do suck out of the vent, the fuel wont drain out the bottom and you'll effectively run out of fuel until you can get air back into the tank

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Re: Fuel tank breather

Post by Vintage man » Wed Mar 28, 2018 3:18 pm

@ Retrovan
Firstly big thanks ,i have done all the new pipes and fuel tank.If you have at look at number 28 that is were i am ,what is that components that it joins to.

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Re: Fuel tank breather

Post by Vintage man » Wed Mar 28, 2018 3:20 pm

Thanks Toney

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Re: Fuel tank breather

Post by retrovan » Wed Mar 28, 2018 6:13 pm

Vintage man wrote:
Wed Mar 28, 2018 3:18 pm
@ Retrovan
Firstly big thanks ,i have done all the new pipes and fuel tank.If you have at look at number 28 that is were i am ,what is that components that it joins to.
I would vent it to the left side air intake vent, away from the battery , but just to atmosphere is fine.

Herman
1952 Split Beetle 1835cc twin 34ICT's (Azure Blue)
1968 Fastback (2Lt.type4)twin 34ICT's( Red)
1972 Low Light Bay Panel Van (2Lt type 4)twin 34ICT's(White)
1975 Fleetline Panel Van 1914cc twin 34ICT's(Aqua Blue/White)

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Re: Fuel tank breather

Post by WolfgangT2b » Thu Mar 29, 2018 12:00 am

Hi Vintage Man,

if you have a 1600 engine it should look like this.
DSC04570b.jpg
I would try to connect the hose to the filter (probably construct a connector), because I had liquid petrol coming out of this hose (full tank in extreme heat). Not much petrol, but enough for a cigarette butt …

Wolfgang
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Re: Fuel tank breather

Post by Vintage man » Thu Mar 29, 2018 6:52 am

Thanks all ,sorted

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