'71 EEC Vent canister Replace or mod/delete?

[DjS71]

Alrighty, about to put the tank back in, want to get all of this handled at the same time.

So there are 3 hoses off the canister, 1 vacuum to the rear high port in the carb, 1 evap line to the lower front of the carb and 1 evap line that runs into the cab, and into the hoop-vent, which then runs into the tank.

So i can replace the canister (which comes out how? take out the inner fender?) and all the hoses for probably $150. OR I can plug stuff off (which and where?) and get a $10 vented gas cap.

Pros? Cons?

I've run the search and found some good info, just wanted to get some fresh opinions, and to not have my freshly coated tank balloon out again.

[69sixpackbee]

I s**t-can everything smog related on my pre-'75 vehicles. Plug it and run a vented cap.
Just my $.02

[webfoot]

Do they make a vented gas cap that actually vents? Cuz I got a "vented" cap and all build up a tremendous amount of pressure.

Maybe just keep the vent line for the tank and use the externally vented feature.

[MARKDTN]

I would keep the charcoal canister and non-vented cap. It is not hurting anything and the gas should be slower to evaporate. You can probably find a good canister on a newer vehicle, like a 73-87 truck and use it.

[hayhauler71]

I left the line on the frame that goes to the loop on the tank open and threw the rest away been that way for 10 years and no problem and no gas smell

[69sixpackbee]

Originally Posted by webfoot

Do they make a vented gas cap that actually vents? Cuz I got a "vented" cap and all build up a tremendous amount of pressure.

Maybe just keep the vent line for the tank and use the externally vented feature.

It's called a drill bit I punched out the one on my '72 as I had to do this anyway for the EFI.

[cdowns]

Originally Posted by hayhauler71

I left the line on the frame that goes to the loop on the tank open and threw the rest away been that way for 10 years and no problem and no gas smell

that is the way i've been doing it and telling people to do it for over 20years never had a priblem or a pressure buildup in the tank

[DjS71]

Hmmm, just the sort of info i was looking for, thanks gents.

[69sixpackbee]

California can ram their smog checks for all I care. Thank God all but one of my vehicles is exempt! And you poor folks in certain parts of AZ who have to hit the sniffer with older iron, my heart goes out to you A bit off topic but still smog related.

[SkeksisNV]

Good info here. Even though I still have to smog check my vehicle, these items tend to be overlooked. They just check the gas cap and hook up the sniffers.

[RichardJ]

You guys act like there is something evil about the charcoal canister. That is ignorant. They may be ugly and the extra vacuum lines unsightly, but a sealed fuel system is a good thing. This is especially true for old cars and trucks like these that may sit for days or weeks at a time.
It is never a good thing for gas to evaporate out of the carb. Todays crappy gasoline evaporates even faster than the fuel sold in the '70s when these canisters were introduced.
For those of you that ever worry about fuel mileage, you should want the charcoal canister to function properly. The gas that evaporates out of the tank and carb bowl when the engine is off, is stored in the charcoal. When you start the engine and drive down the road the gas is being pulled out of the charcoal for the engine to burn.

In CA they no longer just test the gas cap for certain year cars. OBDII cars, '96 and newer, the car's computor self test the Evap system. For OBDI cars, '81 to '95, the smog test includes pumping Helium into the gas tank. The Helium has to stay under pressure for a specific period of time. That tests the tank, canister and hoses up to some systems on the engine.

The first time my '87 vette was tested for this about five years ago, it failed. I fixed it myself and found two deteriorated rubber hoses and one steel line with a hole in it. It was a pain to find and fix, but I'm glad an unknown problem is now good.

[69sixpackbee]

Gas evaporates out of the carb regardless of if it is hooked up to a charcoal can or not. Hogwash. The newer reformulated, higher oxygenated fuels, are designed for fuel injection vehicles. That is why we suffer from percolation, vapor lock and the like.

If you guys are so bent on keeping it, great. No harm, no foul. But, for me, that is just one less set of hoses and unwanted crap on my vehicle.

Good luck,
Bud

[djw32]

Originally Posted by 69 1/2 Six Pack Bee

It's called a drill bit I punched out the one on my '72 as I had to do this anyway for the EFI.

Do you have a picture of how you did this? I'm trying to find a easy/aesthetically pleasing solution.

David

[sleepertruck72]

I say get rid of it and use the vented cap.

[MagmaJct]

Do as you wish, it's your truck. However, I would like to ask that you at least hold on to the parts for someone who may want to restore their truck to original. I've owned older vehicles for many years. I've seen people trash parts, only to later encounter someone who's been looking for that part for a very long time to complete their restoration. Just because it's "junk, crap, garbage, stupid" to you doesn't mean it isn't the last piece of the puzzle for someone else.

[DjS71]

Gonna dredge this up again, was trying to dial things in after a carb rebuild and my canister has a pretty decent vacuum leak (So did the flapper on the heat stove valve in the air cleaner, for that matter.

I'm not keen on the idea of an open hose from the tank, do you fellas think this would be adequate?

[cdowns]

Originally Posted by hayhauler71

I left the line on the frame that goes to the loop on the tank open and threw the rest away been that way for 10 years and no problem and no gas smell

that is the way i've been doing it since when the trucks were new


have seen SOOOO many problems over the years with people plugging and trying to vent in other ways that i cant list them all

[ARC190]

Smog stuff aside, any tips/issues? I'll be replacing my tank in the next couple months. I plan on replacing the sending unit, tank, and filler neck gromet.
Posted via Mobile Device

[corndoggydogg]

Originally Posted by 69 1/2 Six Pack Bee

It's called a drill bit I punched out the one on my '72 as I had to do this anyway for the EFI.

Hello. Where did you drill the hole? And how big?