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Fuel Vapor Separator

Rumrunner

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First time on the forum
Restoring 68 Roadrunner w/68 383 roadrunner engine, A833 four speed.
Two vents coming out of fuel tank. One goes up through the body and loops back down.
Is the other one a return for a "fuel vapor separator"?
 

Russ69Runner

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Welcome to the sight. I believe one goes to the gas filler neck. Or it is for electric fuel pump return line. Took my car apart some time ago and really don't remember seeing two vent. One vent and one to furnish the fuel. Good question. Some one will probably know more than I do. Glad to have ya with us. :thumbsup2:
 

Rumrunner

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Thanks for replying.
No electric fuel pump. Nothing on the neck.
On the back of my tank, there's the supply line and electric post on tank gauge sending unit, it can and has been replaced. Then over about six inches to the top are two vent tubes. Hooked up one goes up through the body and loops back down.
I've read a LOT more about FVS and it appears they are standard on 440ci and 426 Hemi engines to prevent vapor lock. I've not seen any reference to one on a 383. Maybe the tank was changed out along the way?
When I got the car, I did not come with it. I thinking I will install one anyways. Can't hurt?
Would appreciate any more input on this.
 

69hemibeep

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3748024-DSCN273928Custom29.jpg One vent goes up into the trunk and back down onto the outside the other goes straight up into a little metal J shape. Vapor separators were used on Hemi's and 440's and used a different fuel pickup at the tank and separator at the engine with a return line to the tank.
 

Rumrunner

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My new question is,
Why wouldn't a 383 HP not require a fuel vapor separator that's required on a 440 or 426?
 

Big Mo

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My new question is,
Why wouldn't a 383 HP not require a fuel vapor separator that's required on a 440 or 426?
I can't answer that question but I also am restoring a 68. I just put a new tank in and the pic above is correct. Big Mo.
 

dmartin

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Oh yeah looks like you got a good project car welcome from the peach state with the wave we like lots of pics
 

69hemibeep

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My new question is,
Why wouldn't a 383 HP not require a fuel vapor separator that's required on a 440 or 426?
The 383 used a 5/16 fuel line the 440 6bbl and Hemi and I believe 440 4bbl used 3/8 fuel line for demand and 1/4" return from the separator which keeps the fuel cool. It's not a bad idea if you experience vapor lock on any car. Why not on a 383 car? Probably cost and less fuel demand.
 

Russ69Runner

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Did not have that J pipe when taking my car apart and believe the other vent pipe was plugged off. So I did have the one that went up through the trunk and across and back down into the frame rail. Sorry I was not much help.
 

Rumrunner

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Thank you. And all the responses and picture were helpful.
My fuel supply line off the tank is 3/8". I will be installing a fuel vapor separator for no other reason than Why Not. Do I attach it with the outside bolt on my fuel pump? or I will need to put it on the inside of my fender?

I read an old blog last night on this subject and a question was "can he mount the FVS horizontally"? I'm looking at the cross section of a FvS in the book and and it appears it needs to be perpendicular to work properly? And the pic
S. Bob attached for me is a lot clearer than the one in my book. Thanks.

Installing the engine today!

As soon as I get smarter, I'll get some pics on my project.
 

69hemibeep

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It's the small black canister mounted with the fuel pump. You can buy fuel filters that do the same thing.roadrunner restoration 680.jpg
 

jww69rrpost

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I had a real problem with fuel purging out the vent tube (single vent tube) and after going through all kinds of setups, I finally went with a dual vent system and incorporated a vapor canister in the system. NOTE: I also have a Ricks aluminum tank with an in-tank pump, and the design of the tank places a portion of the vent tube (in the tank) below the fuel level in the tank, so that under any pressure, the fuel would be purged out the vent tube, until the fuel level would go down; however, even after the fuel level went down there was always the smell of fuel in the garage as a result of vapor being released through the vent tube. The design of my current system includes two vent tubes... one originates where the original stock tube came from. The second vent tube comes from the fuel fill neck. I had a threaded bung welded in the fuel neck. The two vent lines are routed into the truck where they are mated together at a Y-fitting. From there the tube goes into a vapor canister, mounted backside corner of the the trunk, then exits the canister and goes through a hole that leads to the outside of the trunk and runs a short distance away from the tank and rear tire. This system is extremely neat and clean and permits filling the tank completely full without any fuel purging or vapors. The vapor canisters are a bit pricy, but worth every penny. The best part, other than no fuel leaking, is when I walk out into the garage, there is absolutely zero orders. Even my wife has stopped complaining about the horrible smell that used to come from the car. I would routinely get a bunch of grief about the smell and was constantly told that if the smell did not go away, the car would have to be parked outside. All is good now... happy car, happy wife.
 

jww69rrpost

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If you talk to twenty Mopar owners, you'll likely get twenty variations on how to best solve the problem of fuel vapor and fuel leak issues. All I know is that what I finally ended up doing works very well and also looks clean and neat... not a lot of tubing going all over the place... two vent tubes to Y-fitting in the trunk to the trunk-mount canister and out of canister to atmosphere. The canister is what removes all the vapor odors. I don't recall the name of the canister, but I do remember it came from Canada (that is where they are manufactured). During the course of the restoration/build process of the Road Runner, I ended up purchasing quite a few parts made in Canada and I have to say I was never disappointed in the fit and quality of the products... much nicer than a lot of the stuff that originates from China. But I do have to admit, there are a few parts on the car that came from China, but I'd have to say that at least 95% of everything on the car was make right here in the USA... approximately 3% from Canada and approximately 2% from China.
 
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I had a real problem with fuel purging out the vent tube (single vent tube) and after going through all kinds of setups, I finally went with a dual vent system and incorporated a vapor canister in the system. NOTE: I also have a Ricks aluminum tank with an in-tank pump, and the design of the tank places a portion of the vent tube (in the tank) below the fuel level in the tank, so that under any pressure, the fuel would be purged out the vent tube, until the fuel level would go down; however, even after the fuel level went down there was always the smell of fuel in the garage as a result of vapor being released through the vent tube. The design of my current system includes two vent tubes... one originates where the original stock tube came from. The second vent tube comes from the fuel fill neck. I had a threaded bung welded in the fuel neck. The two vent lines are routed into the truck where they are mated together at a Y-fitting. From there the tube goes into a vapor canister, mounted backside corner of the the trunk, then exits the canister and goes through a hole that leads to the outside of the trunk and runs a short distance away from the tank and rear tire. This system is extremely neat and clean and permits filling the tank completely full without any fuel purging or vapors. The vapor canisters are a bit pricy, but worth every penny. The best part, other than no fuel leaking, is when I walk out into the garage, there is absolutely zero orders. Even my wife has stopped complaining about the horrible smell that used to come from the car. I would routinely get a bunch of grief about the smell and was constantly told that if the smell did not go away, the car would have to be parked outside. All is good now... happy car, happy wife.
hey a question on your set up. you used both nipples from the tank into a Y with one out to the canister? any return or just 1 out the other side back to the frame rail
 

cosgig

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The 70 cars ran a fuel separator, and dual vent lines on the tank. It is not a vapor separator, it is a fuel return line back to the tank, meant to always circulate the fuel in the line to keep a steady supply of fresh, and hopefully cooler fuel, to the engine. I run it all, and I put an inline filter before the separator for good measure.
 
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