Boxer fuel tank vent?

I have an 84 at work and will look at it Monday. If yours was federalized as it should have been its stock vent will have been changed anyway. IIRC there is a small plastic hose attached to the fuel filler pipe (just below the cap) that just goes to atmosphere on a stock car. On federalized cars they usually send that hose to the charcoal cannister. All breathing takes place through the charcoal to filter out vapor.

 

That hose on the pipe is the one I was referring to. You have to remember that when running, the direction of flow for the most part will be suction into the tank to replace the volumn of the fuel being burned. Outflow for the most part takes place when the car is static and environmental heating causes expansion in the tank. Under those circumstances the cannister will store a percentage of the vapor waiting for the motor to be run but excess will be allowed to vent through the charcoal who's duty is to remove the hydrocarbon.

In any event I believe working from an imperfect memory that the routing you describe for the vent hose is stock. You could ck in an original parts manual to see. The pictures for much of the plumbing is often quite an accurate guide. Your car sounds as though it got about as complete a federalization as many I have seen.

 

Frank,
The hose of the filler pipe is the original vent, that is what it left Maranello with. The second hose was added to run tho the charcoal filter during federalization. Funny story: I had the Boxer at the NJ/PA concours at West Point in 2003, the guy from ClassicCoach who was judging comes over to my car, looks in the engine bay and removes the second hose and the charcoal filter and throws them in a trash can! All the while saying "you dont need this stuff, itsa gotta go.."

 

So did you pick it up later out of the trash and reconnect it or did you follow his advise

 

The splash tray at the fuel filler has its own drain, not counting that one according to my various manuals and a car here as confirmation there is a large nipple about 14 or 15 mm for a hose to the top of the right side tank. That hose is to prevent that tank from becoming air locked when filling the tanks. There is a 6mm or so nipple for a breather hose that runs down to about the lower inner control arm mount for actual breathing. On a federalized model it would be, among others connected to the charcoal cannister. In at least one of my manuals for carbed BB's it shows an additional nipple for the return from the carb fuel supply.

If you remove that second smaller hose as you refer to it you will plug the only vent the system is supposed to have. I saw that done once and the fuel pumps have the power to cave in the fuel tanks, They can get quite small.

 

I dont have a charcoal cannister, just the hose off the splash tray by the filler. I do not think the orgional gas caps sealed in such a way as to require separate vents.

 

Of the three parts manuals I have it is shown in two. Also the BBi I currently have in the shop has one in the filler neck and it is an original installation, not a federalizer mod. Also don't forget those were still built at a time when changes were done at a moments notice. Never and always are two words that are very dangerous to use on pre 348 or TR Ferrari's.

 

Since he was the judge and had an accent, I took his advise and left it in the trash!!!!