fuel vent? (1 Viewer)

[2manycruisers]

So I don't hijack the other fuel vent thread, I just bought a '71 pig and filled the tank up. It's been sitting in the driveway since, but when it warmed up in the daytime (80-90 degrees) gas leaked out the filler under the cap. After a couple days of this, I drained about a gallon or less. It still did it. So I drained another couple gallons and it stopped. I haven't investigated this yet, but thought I'd throw it out and see if anyone had a quick response.

thanks,
david

 

[nuclearlemon]

new fuel cap...one that vents.

 

[snailwagon]

Parked at an angle? Not a venting problem of the tank itself if you can fill it up with fuel all of the way.

 

[2manycruisers]

flat ground, so the only angle is the Cruiser Lean.
Why would I need a vented cap now if it didn't need one 30 years ago? It has an original Toyota locking gas cap on it

 

[snailwagon]

Now this is interesting. With a non venting cap, the only place to go with pressure is into the fuel pump and there on. If it wasn't venting at all, how could gas escape from around it? I had overflowing problems recently, but this was because of a mild angle at full tank and excessive vapor lock had no where to really go. My 69 came with a vented cap, now I am running a late 70's style filler with a cap that looks like there are some vent holes under it.

Did you smell gas in the cabin after filling it up? Maybe a vent line is disconnected on teh filler neck and allowed you to severly overfill the tank. Expansion rate of most liquids up to a much warmer temp is around 4%, and the temp underground from where the fuel is stored is pretty cool. No flaming pigs.

 

[2manycruisers]

I haven't smelled any fumes inside the cabin. The po gave me the original non locking gas cap and the locking one he bought from Toyota. Maybe I should fill the tank up again and try the other gas cap. But with only 4% expansion, I was really surprised that it overflowed after draining nearly a gallon from it.