check-valve foam replacement?

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milo
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Your car is a: 1971 1600

check-valve foam replacement?

Post by milo »

Fiat friends,
In chasing a vapor lock issue I removed and cleaned the plastic check valve from the vapor-capture system that's bolted to the inside wall of the trunk. The check valve assembly comes apart with one piece that sits against the trunk wall and the other that has the two hose nipples and the cylindrical gizmo that (I guess) is the valve. Between the back and front pieces was a layer of foam that's completely disintegrated. Any suggestions on what I can replace the foam with? To get things back together I scissored a cotton shop rag and stuffed it where the foam used to be, but I'd like a more appropriate replacement.
Thanks, Milo
Nut124
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Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: check-valve foam replacement?

Post by Nut124 »

That fix would be OK with me.

What problem were you trying to solve in the first place? Is that fixed?
Integrale
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Your car is a: 1980 Spider

Re: check-valve foam replacement?

Post by Integrale »

you could probably use some foam from an air cleaner element for a lawn mower.
milo
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Re: check-valve foam replacement?

Post by milo »

Thank you both. The problem was fuel starve under load. I cleaned the fuel pump (mechanical) and the carb and replaced some lines, but the trick seems to have been the plastic gizmo in the trunk (so far, so good). I think it was so old ('71) that it was sticky and sometimes not letting air in the tank. I cleaned it with some isopropyl and some carb cleaner, plus rapping it against a piece of wood to knock things loose. It may have been the carb cleaner that destroyed the foam, but that was ancient anyway. I may buy some air cleaner foam as suggested to make a neater fix than the cut up shop rags, now that I have some understanding of what the device does.
18Fiatsandcounting
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Your car is a: 1969 and 1971 124 spiders
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Re: check-valve foam replacement?

Post by 18Fiatsandcounting »

milo wrote:I may buy some air cleaner foam as suggested to make a neater fix than the cut up shop rags, now that I have some understanding of what the device does.
That should work. This gizmo does three things: 1) it passes gas vapors from the tank up to the charcoal canister in the engine compartment, which are subsequently burned when the engine is running, 2) it lets air into the gas tank so as not to build up a vacuum as the fuel is used up, and 3) it vents the gas tank should it become overpressurized. I'm thinking the small filter is to keep dust and such from getting into the tank under situation #2.

-Bryan
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blazingspider
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Your car is a: 1977 fiat spider
Location: Nanuet, New York

Re: check-valve foam replacement?

Post by blazingspider »

I used a piece of foam that I cut out from one of these foam paint brushes.
milo
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Re: check-valve foam replacement?

Post by milo »

Understood that this is now an ancient thread, but the ultimate fuel starve problem turned out to be the fuel pump. At high flow rates it would leak air along the gasket where the top and bottom join. Once replaced (fun, that), the problem went away. I'm still running with the cotton cloth replacing the degraded foam in the check valve in the trunk. If I have some reason to go back there, I can try the foam suggestions, but since it's old and plastic, I'd just as soon not mess with it if I don't have to.
Thanks for the input, all.
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