Thread: Gasoline odor

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Originally Posted by rspears

Dave, I don't think you want that first part of your loop because if you will tend to condense vapors over time and they will settle in that low spot. I believe your hose should slope up from the vent connection to your high point, then perhaps turn down. I still don't see any value in having it drop down to tank level, but I don't think you want any low points in that line.

I think I will add a riser like yours to my trunk mounted tank, just for grins. My vent line will run up to the top of the trunk, only about 6", then drop down to a drain fitting through the floor.

Roger, at this point it's trial and error with the hose held only by cable ties. What I did is put a basic liquid trap in the line. If it doesn't work, then I'll see what else can be done including your suggestion. Unfortunately I'm trying to work with a fully upholstered car, including the trunk and really don't want to pull it out unless that's the last resort

Originally Posted by IC2

Roger, at this point it's trial and error with the hose held only by cable ties. What I did is put a basic liquid trap in the line. If it doesn't work, then I'll see what else can be done including your suggestion. Unfortunately I'm trying to work with a fully upholstered car, including the trunk and really don't want to pull it out unless that's the last resort

Dave,
I understand the pain of working with a newly finished car, and I would consider this to be a winter project, if needed. My concern is that a liquid trap is going to work. You will condense in that line over time, and then once you have a seal the tank pressure has to overcome that seal to vent. At some point you are going to get enough condensation that on a nice, hot day you fill the tank, park in the sun and as the tank expands you will finally overcome the head pressure on the liquid seal and burp fuel out your vent line. I think a vent needs to slope up from source to the peak. A "J" at the top keeps water from entering if you are planning to ford creeks, but other than that I believe it can terminate at the apex. Any condensation of vapors will then run back to the tank.

I guess that the next step will have to wait until Sunday/Monday - I got up at 0 dark 30 this morning and have driven to the furthest corner of Virginia from home, 677 miles. When I left home, no trace of odor, but......more to come, I'm sure.

Originally Posted by IC2

I guess that the next step will have to wait until Sunday/Monday - I got up at 0 dark 30 this morning and have driven to the furthest corner of Virginia from home, 677 miles. When I left home, no trace of odor, but......more to come, I'm sure.

Did you drive the roadster?

well i think it you coil up15 feet of hose lay on top of the tank off the nipple and then run it up thru the trunk till you go up as hi as you can then a 90 run it back out . use a vented cap that should do the job that would be over 20 feet that should do it..... over kill you bet yep i maybe kidding here but not to much if your talking a J bend you could very well start in back of trunk run it up going forward till the back panle of the back of your seat hide it under your side trim of the 1/4 panle hook it to trunk drip rail then run it on the upper back side of the top of the rear 1/4 panle running the hose back thru the hole were it came and then out give you more then a J bend and if the tank get hot and fuel move s up that what really going on here with that low vent point on the tank every time you hit the brakes or if you sitting on a low front rake she going to want to siphon the the vent should be at the hi point of tank just a bad deal less it has some trick baffle and if so its not working very good ?

Dave,
Did you get rid of your gas odor in the garage? I installed a rollover vent extension like yours to be sure I'm above the liquid, but I ran my vent hose out at the 90 and down to a fitting in the floor. I'm getting a strong gas odor, and I guess I need to put a "J" loop in the tubing to hopefully stop the fumes.

Roger - occasionally I'll still get a gas odor, but for the most part gone.

I have some today, but I just had much of my gas line apart for replacement of some "claptrap" so might have a minor leak - which I'm abut to check

This is really strange. After reading the entire thread I can't imagine what would make fumes like that. We had 3 of our cars sitting in the shop with fuel in the tanks and never get any hint of gas odor. We even have one open jerry can that Dan has been using to draw gas out of for his RPU and no fumes from that one either.

My 23 just had a simple vented cap,and my 27 and Dons T have simple hose loops out of the tank vents. Very strange that you are having that issue.

Don

Originally Posted by Itoldyouso

This is really strange. After reading the entire thread I can't imagine what would make fumes like that. We had 3 of our cars sitting in the shop with fuel in the tanks and never get any hint of gas odor. We even have one open jerry can that Dan has been using to draw gas out of for his RPU and no fumes from that one either.

My 23 just had a simple vented cap,and my 27 and Dons T have simple hose loops out of the tank vents. Very strange that you are having that issue.

Don

Don - that vented gas cap may be what I need to install. I shouldn't need one with the rollover valve, but that's about the only thing I haven't done since I don't have a spare plus I really don't want gas to slop on my nicely painted '32 style gas tank (it's a '71 Jimmie cap, I believe that Tanks supplies)

I never had a problem with my '23 either and that only had a roll over valve and an unvented early Jag(?) flip open cap.

Originally Posted by Louey

Have you thought about using a small charcoal canister ? To store the fumes, until you start, and run the engine ?

I still can't understand why any of that would be necessary. On our stuff we are running nothing special, just looped hose or not even that, just vented caps, and not a whiff of odor. Something is odd with this one IMO, maybe that rollover thingie is doing something strange. I could stand right behind any of our cars and even remove the caps and get no smell.

Don

Just a thought, maybe the heat from the exhaust is just enough to expand the gas to start a siphoning cycle, its happened on my `64 pu, with the tank in the cab, on a real hot day, pushed the gas right past the cap and ran back down the filler tube into the cab, it was bad for a week...

Could it be that with a vented cap the odours are released slowly but with a non vented cap pressure builds up and then releases quickly make the odour more pronounced ??? just an idea

Steve - that's a thought as well, but until I get a spare 'petrol' cap am not going to start drilling holes yet.

I just went through my partially replumbed gas line and no leaks. Interesting that the Edelbrock carb seemed to have a slight gas odor around it so I did snug the input fuel line just a tad - but it does make me wonder about the carb itself. This is/was a brand new carb and all of the settings were checked when I originally set it up identical to an earlier carb that was on a 351W. I don't have a pressure regulator on it, but possibly it needs one as I have no idea what my fuel pressure is except that the Carter mechanical fuel pump was supposed to be the 6psig version - (hmmmm more AN fittings) The gas cap was loose so that might account for some odor. That cap does have a check valve to allow air in, but not out.

Oh well - gonna reset the coil overs and shock adjustments as I've procrastinated long enough about crawling under the car.

I just talked to Lee at Tanks, Inc and learned a few things. First, my billet cap did not have the thick o-ring gasket, so my odor in the trunk is most likely due to my cap not being sealed. Tanks is sending me an O-ring which they say is very thick and heavy, rated for fuel service.

Second, their brass anti-rollover valve actually is designed to fit down into the tank as it has two check balls - one is phenolic and floats up to seal the vent with slosh with a full tank (not supposed to be topped off, but if it is...), and the second is stainless to drop down if the tank/valve becomes inverted. Mounting it extended above the tank is fine, but Tanks does not consider that to be necessary with their dual check ball design.

Lee says that it is normal and expected to have a slight gas odor from the vent in a closed garage, especially as the tank warms as ambient temperatures increase since our applications do not have the modern OEM vapor recovery systems and charcoal filters.

Hopefully the O-ring gets rid of a lot of my gas aroma, and I am still going to get a longer hose for a up & down loop seal.

Those billet caps can be a PITA on a steel filler neck. Crossthreads, galling, etc. I had to replace mine because Gibbon had cross-threaded it. Every now and then, I put a little anti-seize on the threads.

I also installed the Tanks, Inc. rollover valve, and once I replaced the cap, I had no gas odor.