8/24/2019 Update (Post 40) Current Reproduction Fuel Separator Valves Are Dangerous

8/15/2019 Update (Post 37)


My '73 has the fuel separator valve mounted on the top driver's side of the tank. This valve has a hose that runs to the vapor canister.I'm now on my 3rd valve in the last 10 years. First one leaked due to a crack in the body. Second one had a cracked nipple.The third one is allowing fuel to get to the vapor canister if I fill the tank all the way to the bottom of the filler neck. The first two did not do this.Is this a check valve? Should it allow fuel to pass?What I'd really like to do is to eliminate this valve and replace it with a higher quality 3rd party valve of some type. Originality is not important here. Any suggestions? If it makes a difference, at some point down the road, I'd like to fuel inject this engine (another possibility is an LS swap).The pic below is the valve in question.Thanks much,DC

 

Don't fill it up so much.
An inch or so below the neck makes my gauge go to full and the fuel separator works as designed.

 

Yes, it's just a big check valve. There's a @ping pong size ball inside that rises when liquid enters and closes off the port. When it's not closed off it simply allows fuel vapor to be drawn from the tank to the charcoal tank then into the carb for burning.

 

Not helpful. Also not an option. I fill it to the same place every time. I didn't have the issue with the first two valves regardless of fill level.

I'm looking for a better solution than the factory valve.

Thanks. Hopefully someone has already found a 3rd party solution so I don't have to re-invent the wheel on this one.

DC

 

the ethanol in todays gas may be causing problems with the plastic the valve is made from.

 

I wouldn't be surprised if this is the case.

I am surprised that I haven't gotten any replies from anyone who may have already gone down this road and found a better aftermarket or third party solution.

Maybe this bump back to the top will put some more eyes on this one.

DC

 

There are no aftermarket or third-party solutions, you either have a bad valve or are filling your tank too much.

 

I've had drag boats in the past where you fill the fuel tank too high and the gas will blow out the fuel cap vent and run down to the transom ruining your custom paint.
Same on my custom motorcycles. Over fill the tank and when it sloshes or expands that fuel goes somewhere.
I'm in the habit of putting the fuel hose nasal fully into my tank and when it stops automatically, don't top it off. It may be down an inch but I've never had any issue on boats, bikes or on my 73.
I replaced the fuel separator valve when it was cracked with a new one last year and haven't had any issues.
Just don't overfill your tank.

 

I don't believe this for a minute. There are literally hundreds of aftermarket fuel check valves available for sale. I was just hoping someone had already converted theirs and had some advice.

I have a bad check valve. I've already said I only fill the tank to the bottom of the filler neck. This was never an issue with the first two check valves.

These reproduction valves are simply cheap pieces of crap. I'm looking for a better quality solution.

DC

 

I have the original valves on two of my cars - no issue even when I "overfill". The valve on the 3rd car cracked some years ago. My first replacement leaked. My second replacement works to this day.

 

Thank you. There shouldn't be an issue when overfilling. The valve is designed to block the flow of fuel. I'm just not having any luck with the reproduction parts available for my '73. I may have to go down that road again but hopefully I can find a better solution. Where did you source your replacement valve?

There are a lot of vehicles still on the road that use some variation of this valve. I know that I won't find an aftermarket solution specifically designed for my '73 but I am hoping to find a workaround.

I did come across a company out of England called Newton Equipment. They make in-line tank vent valves out of an aluminum alloy. These valves have two interior ball valves, one which allows the valve to vent the tank and the other which is designed to prevent fuel from passing through the valve.

I've sent an email to the company to describe our fuel separator valve and to see if they think one of their valves would be a suitable replacement.

Their TPV series is designed to mount at any angle so I'm hoping that product will work. They are pricey. $130 is the best price I've found so far but then again, I'm on my third valve in 7 years.

Here's a link with some info for anyone interested: https://www.newton-equipment.com/tan...ves-range.html

I'll post again when I get their response.

DC

 

Hi DC,
You certainly do seem to have this figured out!

But, is it possible that the evidence of liquid fuel in the charcoal canister is the result of the canister not being properly purged while the engine is running?

Regards,
Alan

 

Got mine from Zip.
I think the real issue with these units is the connector pipes crack when stressed. Second time I installed it I made sure that the two lines running to it put zero strain on the connectors and also used the spring clamps vs. cranking down on a screw on hose clamp where each twist of the screw torques laterally against the connector pipe. Due to the location (and depending on the size of your arm) installing this part without stressing it requires a great deal of patience.

It's likely you can JBWeld/glue up the cracks and see if that resolves your issue prior to replacing the unit.

 

Hey Alan,

Appreciate your input. No, the charcoal canister is working properly. When I first noticed this problem, fuel was literally pouring out of the charcoal canister shortly after filling the tank and then parking with the nose slightly downhill.

DC

 

Thanks. You've described the problem with my first two fuel separator valves very well. My current fuel separator doesn't leak externally. The valve inside does not block the flow of fuel so there is some type of internal failure.

DC

 

I finally heard back from Newton Equipment regarding their inline tank vent valves. Unfortunately, their valves will not work for our purposes. Their valves are "tank pressure valves". They don't open to vent until a specific pressure is obtained and then they effectively burp the system.

However, their product design engineer told me they are working on developing fuel separators but are at least 3 months out. He was interested in having a spare valve like ours to study but I didn't have one to send him.

If anyone has a cutout drawing or photo showing the internal workings of this separator, post them here and I'll get them to Newton Equipment.

Appreciate all the help.

DC

 

I had one additional thought which prompts another question:

What's different about later model C3s that don't use this fuel separator valve? Just wondering how they vent the tank and get vapors to the charcoal canister but block the flow of fuel.

My '73 is not original so I don't need original parts or solutions.

Thanks again,

DC

 

do not force feed the tank, when the pump shuts off do not add any more fuel. make sure the nozzle is all the way in the filler neck when filling

 

DC, my valve is leaking pretty badly as well, cracked. I just ordered a new one, hopefully it will last for a while. I have always filled my car to the bottom of the filler neck too, without problem.
Greg

 

Here's what I did to my tank- when I added FI



I used a roll over valve from Summit Racing- the tanks highest point.

The originally vented through the gas door boot-That's a GM Power Brake Booster vacuum charcoal canister to kill the fumes.

But changed it to the antenna location- as I have sidepipes now instead of a radio!!

Also as my build progressed- I ended up dropping the tank down a few inched from where it was originally.