Thread: Gas Tank Vent Line

Tweet

Originally Posted by shawnlee28

I would get another charcoal canister from a junker or junk yard ....You will still smell fumes with a vented cap ,get fuel slosh,plus ,if it is a full system ,the engine will clear the canister when running,resulting in better gas mileage ,albeit a slim amount,plus it will not be a stinker............

no you will not smell gas less you are sitting on top of the gas cap when driving down the road come on shawnlee he can run a one way valve on the end a loop of steel tub hirer then the the tank it self vent thru the filler neck like said if he wants to put a one way valve on the end of the loop must be out side fo the tunk can be a pcv valve .he ask if he could plug it yes he can. now should you go find a other one thats is up to him

I'm glad this subject came up. We (my boy and I) restored an '80 Volare Duster a few years back which he still owns and drives. We have a problem regarding gas tank venting but it is the opposite of the one mentioned in this thread.

Instead of pulling a vacuum in the tank as Kitz mentions, his builds up pressure in the tank. Sometimes after driving for an extended length of time then stopping for gas there is so much pressure it almost blows the filler cap out of his hand (his description). When the fuel level is low and there is pressure in the tank he gets goofy gauge readings, like, it shows to be lower on gas than it really is. Could the pressure be pushing the float down into the gasoline and causing that?

The Volares and Aspens of that era ('76-'80) have a big fancy chrome filler cap instead of having a filler access door. I drilled a small hole through the cap so it could breathe, and that didn't help the appearance of the cap and didn't impress the safety inspection guy one bit. Instead of taking the trouble to solve the problem, I took the lazy way out and bought another cap for him to put on before he takes the car in for inspection.

What do I do now, coach?


Jim

Originally Posted by pat mccarthy

no you will not smell gas less you are sitting on top of the gas cap when driving down the road come on shawnlee

I have seen some wild customs ...never know...

Unless he has a 40 acre driveway ,you will smell gas,I meant to say that the vented cap will make pressure resulting in venting out the line that does not go to the charcoal canister,because like mentioned the cap is a one way vent ,meaning the pressure has to go somewhere........it goes out the line that has no charcoal canister ,therefore it becomes the stinker .........but the vented cap will leak soon enuff.......
My 66 had the vented cap system,its real funny when guys use a non vented cap on these ,The tank has no vents at all... meaning the cap has to vent both ways,most caps only allow air in, when a good hot day came along ,tank inside of cab,the rubber fuel lines under the hood would swell up like a bloated radiator hose.....

Originally Posted by shawnlee28

I have seen some wild customs ...never know...

Unless he has a 40 acre driveway ,you will smell gas,I meant to say that the vented cap will make pressure resulting in venting out the line that does not go to the charcoal canister,because like mentioned the cap is a one way vent ,meaning the pressure has to go somewhere........it goes out the line that has no charcoal canister ,therefore it becomes the stinker .........but the vented cap will leak soon enuff.......
My 66 had the vented cap system,its real funny when guys use a non vented cap on these ,The tank has no vents at all... meaning the cap has to vent both ways,most caps only allow air in, when a good hot day came along ,tank inside of cab,the rubber fuel lines under the hood would swell up like a bloated radiator hose.....

i have welded cab corner in them old chevys trucks and other parts my hart rate allways pick up a bit we put wet rag around the fill cap

That was my starting point on the truck....eliminate interior gas tank at once.....