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Discussion Starter · #1 ·
I recently upgraded my fuel tank to a fuel cell and to stay in accordance with the CA smog Nazis I went the extra mile to ensure the factory LCV was connected and working. The Jeep passed the visual.
There happens to be a small problem with the LVC though. For one, I don't really have it connected corectly. One vent line from the cell connects to a t-splitter and then connects to the bottom of the LCV, I should have connected both top-side vent lines from the cell to each seperate barbs beneath the LCV. This would have offer less resistance to returning liquid fuel to the cell.
Another problem is the LCV just isn't mounted high enough and I don't have room to go higher.
And the last problem is when the cell is full heat expands the contents of the cell pushing liquid fuel into the LCV and over-burdening it. The needle and seat will shut and push fuel through the cheezie hose clamps. If I open the seal fuel filler cap enough to vent it the problem ceases.

Here's my idea.
I'm going to use a Holley fuel bowl with float assembly mounted to a section of 2"x3"x.125"wall steel tubing. The fuel bowl has the needle, seat and float to stop extra fuel. The larger tubing will allow alot more fuel but I'm planning on using much larger line as to eliminate line pressure created by heat.
I'll use the fuel bowl feed port from the cell, obviously for the valve seat, with #8 AN line, (a cleaner connection from the cell). At the bottom of the tubing will be another #8 AN line for liquid return. At the top of the tubing will be yet another #8 AN line for vapore to the charcoal canister but this one will have a small liquid partition to resist liquid slosh.
Here's the starting pics;

This is all stuff I have laying around from old projects.
Will it work? Who knows, but it's gotta be better than what's in there now, safer and a dry charcoal canister.
Any thoughts?
Does anyone make these for race cars or sports cars?

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9,790 Posts
I should read this board more often.

I just eliminated the LCV from my CJ-7, cause I forgot to remove it from the tub when I swapped in a YJ tub. So, I've just capped the tank vents with rubber hoses, and bolts plugging the hoses. Viola, no more plumbing problems.

Now, I've run into a number of other problems, like going through fuel pumps and starving my engine for fuel, do to the lack of venting, and the negative pressure which builds up in the tank.

So, conviently enough, the YJ tub has an axle vent located in the same corner of the tub as the old CJ LCV (left rear). So, this is now my temporary tank vent, to keep me from eating fuel pumps.

The local recker has JACKED up Jeep parts, so a jeep LCV is outragious.

I plan on re-installing one, i'm just going to have to wait a bit. It's turning fall/winter now, so the evaporation and fumes aren't nearly as bad as when I first vented the tank, but I do plan on fixing this problem by spring.

And thanks to you, I now have an Idea :idea: how to.


just one question, did you hook the vapor line back-up to the charchol canister? or just directly back into the air cleaner housing. (where I'm thinking of plumbing it)

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5,742 Posts
Discussion Starter · #6 ·
For some reason my post didn't subscribe me to replies, so I thought no one was interested and this thread went by the way-side.

Well then....here's a little update.
I haven't finished it yet and I'm still struggling to believe it will actually work.
Why? The ROV (rollover valve) takes in fuel and the damn little ball doesn't allow it to drain back quickly, (quickly, the keyword).
The other topside port on the other hand is free flowing in either direction. The heat and internal pressure inside the full cell will push fuel into the fuel bowl of the LCV, and keep pushing it b/c the damn little ROV ball. The non ROV top port will slosh and push fuel up but will also allow the fuel to return as long as there's room. The LVC will always be vented to the canister but the problem may be getting some liquid fuel into it. A better series of baffles inside the LCV reservoir could totally elimated the liquid from saturating the canister. I didn't add baffles, too lazy but it would be simple to make the reservoir a little more elaborate.
Here's the latest basic pic;

This pic elaborates the ports functions;

The top vapor feed could be moved to another reservoir that also drains liquid back to the LCV reservoir, but I'll check this way first.
I had to do something about this because I've been seeing way too many fuel cells spitting streams of fuel. Thta's just as bad as gear oil on the trail and much more dangerous for us driving.

BTW, My Jeep just passed the CA smog test, both sniffer and visual with the fuel cell. All the research paid off.

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5,742 Posts
Discussion Starter · #7 ·
JumpinNRollin said:
Will that float get stuck on off camber or steep climbs and possibly cut off the fuel supply? The reason I ask is I use to have TONS of problems with my carbed motor because of this issue :confused: .
It's not quite the same as a feed problem to an engine fuel delivery. This LCV will do all the hard work when the fuel cell is full. If the float shuts the fuel, it only shuts liquid fuel into the LCV but the cell is still vented.
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