348 anti rollover valve/anti tilt valve replacement

It's Stooge time!

A little back ground.

A few years back I replaced the charcoal canister purge valves http://www.ferrarichat.com/forum/technical-q-parts-sponsored-algar/241642-348-vapor-canister-purge-valve-removal.html While that took care of the implosion problem I later developed the opposite problem. This time instead of the gas cap being sucked down, when I opened the gas cap I had fuel fumes blowing OUT! This is very dangerous as it is the fuel vapor that ignites and catches fire.

So during my engine out major I decided to tackle the problem. I found that the old anti rollover valve (anti tilt valve, as Ferrari calls it) was getting stuck. I figured this out by first removing the valve, then attempting to blow air through the inlet of the valve, and I could not get any air to go through it. Either forward or backward. I also tested the charcoal canister and it was fine, air was coming out the top vent cap when I blew into it. So a quick call to Daniel-San at Ricambi and the new valve was on its way.

 

The anti rollover valve is located up under the left rear fender/splash guard, near the charcoal canister, and just above the fuel tank fill hoses. You will need to remove the rear wheel and fender liner to get to it.
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There are 2 vapor lines you will need to remove.

The one on top (with the clamp, kind of hard to see it because the pic is so dark) is going to the tubing for the purge valves.

The line on the bottom is coming from the fuel tank.

Remove both lines from the ROV (roll over valve).
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Next remove the nut attaching the clamp to the fender, and remove the old ROV.
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I know the new valve is working because I can now hear the hot fuel vapors blowing past the valve. It has the faint sound of someone playing a Cazoo. One more thing, when you put the new ROV in you will find the word "tank" stamped on the bottom of the valve. Be sure you hook up the line coming from the tank to that nipple. The nipple on the top (the white part) goes to the purge valves.

That's pretty much it. Nothing really hard about the replacement.

Happy Wrenching.

 

The rollover valve is nothing special. Ferrari got it off some other car. Which car? I haven't spent the time to actually figure it out. But if you look you'll find it.

Either that or find a anti rollover valve off another car that will work. After all that's what Ferrari did anyway.

 

Way too much pressure. It would rush out as if you stopped pinching a balloon.

 

I didn't crack it open.

However I could hear a ball inside when I gently shook the new valve. I could not hear the ball rolling around in my old valve when I shook it. I got the ball in my old valve to come loose after I banged the valve on my work bench a few times. Some more test shaking of the old valve and it got stuck again. If the steel ball isn't loose to move around the vapors from the tank get trapped and won't vent into the charcoal canister. My guess is that after 25 years it has some built up varnish on the steel ball, and maybe even gummed up a bit inside the housing.

 

Nice find Steve!