venting vs non-venting gas cap

My gas cap does not vent. I need to keep it cracked or my jeep pulls a vacuum and dies. I see there are non venting gas caps. How exactly does that work? A tank vent? My issue is that my fuel evaporates before I can burn it and fuel does leak out somewhat.

 

I want a non vented cap does it have any part numbers?

 

No, no part numbers. It looks to be an original CJ2A cap front epics i can find online. I also looked at it a little closer. it had an opening in the center of the cap and another one on the ouside of the sealing ring. obviously it is vented but clogged.

 

So this is an under-seat tank? AFAIK no non-vented caps exist for that application, unless you found one from another application that will fit. In theory, a non-vented cap will not work with that system. The fuel pump will evacuate the tank and cause fuel starvation.

 

yeah thats what i have. It actually IS vented but just plugged with something. I will have to clear the vent.

 

My opinion. Don't buy a reproduction cap. I bought a repop and it leaked gas all over my jeep at the slightest angle. Then I bought a Nos cap on ebay and no more problems

 

Keep the cap plugged if it doesnt leak when wheeling radically. add a breather to the tank.

I'd love my cap to not leak. Doubled up the seals and nearly had it, but still not it...

 

The original Eaton caps had four vents around the perimeter, and a ball valve inside that was supposed to prevent leaking......I used spray brake cleaner to clear the vents, but the ball valve doesn't really work that well....

 

mine has a hole in the center and a hole on the other side of the seal on the outside of the seal area where it contacts the tank. It is obviously plugged. It might be easier to just vent the tank using one of the screws for the sender cover. I had to run a return for my fuel pump that I plumbed into my tank.

 

Got a part #? How off camber can you get without leaking?

 

Thank you.

 

If your cap does not leak, I'd suggest you keep it and fit a vent. Not surprised that the OEM caps work better.

Back when I had my '73 CJ-5, I bought all-new parts from the dealership where I worked to put a tank under the driver's seat. The cap we stocked came in a Stant box, not Jeep packaging. When I asked about that, the parts ordering lady said they were much cheaper from local AP warehouse than from Jeep. They were then selling them for the Jeep list price. Of course, it leaked.

 

Might leak, i haven't had it at an able yet to notice. i would like to remedy that angle problem to see if i can get it to leak. I will be installing a tank vent as soon as i see what Mr. Patricks looks like.

 

When I installed a gas new tank, I went with a non-vented cap and added a fuel tank roll-over valve.

http://www.speedwaymotors.com/Fuel-Tank-Roll-Over-Vent-Valve,5848.html

 

I will be installing one of those. thanks.