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Petrol tank breather system, why.

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Why is the fuel tank breather tubes running over the top of the rear cabin glass ? Mine were disconnected and probably the reason for the strong smell of petrol when window was open. They are just vented underneath the car so why run over the rear screen ?.     

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The pipe beneath is full of fuel so cannot help the vapour to move. As the volume of fuel changes between tanks for example in a long corner if there was no breather hose about the air and vapour would have nowhere to go and something would go pop! The top hose just makes the system into a circle.

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The vinyl hoses used by Lotus deteriorate from the fuel, possibly that is why they were disconnected.

 

Many of us have used gasoline hose, but that resolution requires fitting different sizes along with reducers. (As the O.D. of the rubber hoses is bigger, a smaller I.D. needs to be used.)

 

Also, don't forget to replace the additional tubing over the right gas tank.  Be aware that some of those hoses have metal reducers in them, so don't forget to re-install the reducers.

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I'm still trying to figure out what the original breather setup should be like on s2.

 

All the pipes were crumbling apart or missing when I got the car

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On my 1988 N/A car which I believe is the same as the Carb Turbo of the same year, I replaced mine with some similar clear plastic tubing but rated for fuel and ethanol from RS Components.

 

Might be worth checking.

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On mine the deterioration was clearly caused by the glue that secured the hose - not petrol vapour.    Anyway I just replaced it some 5 years ago with some generic clear plastic hose from B&Q and its still fine  

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You should be using fuel hose since it's full of fuel vapour in an ideal world. 

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I would be eternally grateful if someone can take some photos of how the breather system should be set up .. There is something in the lotus manuals but I don't find it clear enough, especially when it comes to fitting the valves

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Thanks all, as the system is terminated as an open drain underneath the car I've routed each tank breather separately with anti-surge valves as a  drain under the car. Don't fancy pulling the carpet away from over the rear window, it's stuck like sh1t to blanket.

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I have a feeling that there is a reason why the pipes are routed how they are.

I think it's to do with possible fuel leakage through the system in the event of the car being rolled.

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Thanks all, as the system is terminated as an open drain underneath the car I've routed each tank breather separately with anti-surge valves as a  drain under the car. Don't fancy pulling the carpet away from over the rear window, it's stuck like sh1t to blanket.

Doesn't the 1988 turbo have a charcoal canister in the breather system?

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Yes, the charcoal canister (cylindrical object center of tank board) is mounted top of the RH fuel tank.

 

Easily accessed (five screws) by removing the carpeted panel near the window. (No need to un-glue anything there)

 

Don't all markets have this fitted?

 

 

++++++++++++++

 

 

The vinyl vent line over the bulkhead window IS glued, but the carpet is easy to peel down. Then, use contact cement to stick it back up, over the new hose (which should also be glued in place).

post-424-0-72763300-1423323072.jpg

Edited by CarBuff

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Yeah but the CC was not a Bosch-only thing.  Any North American car from mid-70s -up needed one to be sold in the USA.  So the Carb'd US Esprits must have had them as well.

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Just had another look and my car has a large circular hole cut into the top cover of the left hand fuel tank, looks like it once had a charcoal canister installed, interesting !!

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