Need to install a tank vent,suggestions please !

michel schryer · #1 (**permalink**) 05-11-2008, 06:30 PM

My gas tank came with no vent system,i'm concern about a lock in the system and i would like to make some kind of venting system. All i have is a small 90 degee elbow on the side of tank and the hole at the bottom to install the fuel line to my mechanical pump.
I have very small space between the top of the tank and the trunk sheet metal piece,only 1 inch. I don't want anything to protrude in the trunk so how could i do that. I can't and don't want to weld nothing.
Any body facing the same situation,what can i do ? Thanks !

Michel

DonC · #2 (**permalink**) 05-11-2008, 07:43 PM

Michael:
Don't know about anyone else but ERA uses a pick-off in the filler neck to vent the tank.

Might give you a place to start.
DonC

Rick 427 Cobra · #3 (**permalink**) 05-11-2008, 07:49 PM

Filler neck is always a good option. The higher the better to avoid spillage. Type of connection will depend on the neck construction, metal or rubber. Vent outside the trunk obviously.
If the tank is not installed horizontally, you may have to vent the high point of the tank or it will never fill completely. If this is the case, vent the tank to the filler neck and place an addional vent to the outside higher up on the neck.
Brass fitings can be soldered if you cannot weld. Its just plumbing!

David Kirkham · #4 (**permalink**) 05-11-2008, 09:50 PM

We use the filler neck as well.

David

SF_SN888KE · #5 (**permalink**) 05-12-2008, 01:00 PM

Some caps have vents in them, (small single hole? Could always drill more.) I did this, but also vented the tank to the filler neck.

SF_SN888KE · #6 (**permalink**) 05-12-2008, 01:12 PM

Also, venting the tank (not the filler neck) helps when fueling the tank (venting air out) and prevents 'burping' and gas overflow....

mickmate · #7 (**permalink**) 05-12-2008, 01:23 PM

It sounds like you are using a pickup at the bottom and the 90 fitting is available. I would plumb that up into the rear inner fender. You might also want to put a rollover/spill valve into the vent plumbing. Like Rick said it's just a little plumbing. You could try what you have and see if it even needs venting. It depends a lot on tank shape, angle, fittings location, cap venting etc. Think like the fuel!

michel schryer · #8 (**permalink**) 05-12-2008, 04:27 PM

Thanks to all for the replies,it's my first cobra. I was wondering what was the best technique to plumb a 90 degree fitting from the top of the tank to install a rubber hose all the way up along the filler neck which will be a piece of rubber hose that will connect the cap piece and the tank elbow. I don't know if i can tap fillet in the tank,if there's enough material,would somekind of a bulkhead fitting work if i seal it properly. Somebody suggested soldering the fitting !!

patrickt · #9 (**permalink**) 05-12-2008, 04:51 PM

Quote:

Originally Posted by michel schryer

Somebody suggested soldering the fitting !!

Hmmm, soldering the filler neck of the gas tank. You might just want to farm that out to somebody....

But make sure they have shop insurance before you do.

michel schryer · #10 (**permalink**) 05-12-2008, 05:42 PM

Don't worry it's bone dry,just got the roller,never had gas in it yet !!!

Quote:

Originally Posted by patrickt

Hmmm, soldering the filler neck of the gas tank. You might just want to farm that out to somebody....

But make sure they have shop insurance before you do.

mickmate · #11 (**permalink**) 05-12-2008, 08:44 PM

A couple of questions, why are you talking about soldering or tapping the tank now? What is the tank made from? Aren't you going to use the existing elbow? What thread type/size is the elbow? Why not hard plumb it instead of rubber? OK a couple is more than 2 for me.........

michel schryer · #12 (**permalink**) 05-13-2008, 06:02 PM

I just want to put a vent to my tank there's none,it's a handmade tank from stainless. I guess i'll put a bulkhead fitting at the top and run a rubber line up along the filler neck with a filter or rollover valve for fumes containment. I wish i could post pictures. Thanks anyway,i know sometimes it's hard to picture what people are talking about. Bye!

Quote:

Originally Posted by mickmate

A couple of questions, why are you talking about soldering or tapping the tank now? What is the tank made from? Aren't you going to use the existing elbow? What thread type/size is the elbow? Why not hard plumb it instead of rubber? OK a couple is more than 2 for me.........

michel schryer · #13 (**permalink**) 05-13-2008, 06:05 PM

Thanks Don for the drawing i might go with something close to that,i just want the air to get out when i will refuel one day.

Quote:

Originally Posted by DonC

Michael:
Don't know about anyone else but ERA uses a pick-off in the filler neck to vent the tank.

Might give you a place to start.
DonC

Rick 427 Cobra · #14 (**permalink**) 05-13-2008, 09:56 PM

A roll over valve is designed to stop liquid spills, not vapor. filters will stop particles from entering, but will not stop vapors from leaving. A bulk head fitting designed with a seal would work well. You absolutly need something. Random engine stoppage and a collapsed tank can ruin your day.
Something like this maybe with a nut on the inside
Holley Performance Products -6 AN Male to 1/2"-20 O-ring Port*985065ERL or a
Russell #670850. you can add a AN to pipe adaptor if you want to use plain hose with a barb fitting.

mickmate · #15 (**permalink**) 05-14-2008, 04:57 AM

Roll over valves shut if they are upside down. They are plumbed into the vent on the tank. I like Jegs comment, "the one part we hope you'll buy and never need to use". JEGS Roll Over Vent Valves - JEGS