Fuel Ventilation System - Help!

Need some help with a technical problem - ask away and let's see if we can all help.

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Mat2.2t
DDK Fanatic
Posts: 89
Joined: Fri Sep 02, 2005 4:47 pm
Location: UK

Fuel Ventilation System - Help!

Post by Mat2.2t »

Hi

I've just got a 1970 Targa and would like to know more about how the fuel ventilation system on these early 911s work. I read the Haynes 911 Restoration manual and it describes it as 'wonderful' but doesn't go into too much detail about how it works, what it does and how to fix it.

I'm pretty sure mine can't be working as a couple of the plastic pipes exiting the fuel tank appear to have worked loose from their connections. Do the pipes carry the fuel? or air? How dangerous is this?

(I have a picture of what I'm talking about but I'm not sure how to post it to the board - any ideas?)

Thanks for any help!
Lightweight_911
Nurse, I think I need some assistance
Posts: 18004
Joined: Wed Nov 12, 2003 10:48 pm
Location: Worcs/W Mids border

Post by Lightweight_911 »

There were 2 different systems used on the early 911's :

the first one was used up to '71 & consisted of a plastic 'breather' hose from the fuel tank up to a square plastic 'expansion tank' under the bulkhead in the top left-hand hand corner of the front compartment. Another plastic hose led from this down to the lower left-hand side of the inner wing & through a (grommetted) hole to the outside.

the second system - used from '72 - utilised 2 additional components : a metal cannister (containing activated charcoal) sited down near the left-hand battery & a metal 'expansion tank' in the left-hand wing )up close behind the headlamp bucket).

At the bare minimum I suggest you replace all of the plastic hoses - you can get equivalent hose at B&Q or aquarium supplies shops - otherwise you're likely to experience fuel vapours in the cockpit.
Andy

“Adding power makes you faster on the straights;
- subtracting weight makes you faster everywhere”
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