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air is present in see thru fuel filter

Ray70Chrg

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This is 1st time I've ever used a clear plastic filter and I have used it for a couple of years now. I got it so I can see how much crap has accumulated. From the beginning I noticed their was air in the filter but the engine seemed to run ok. Is it normal to observe this condition or is this a problem? Thanks
 
As far as I know this is common. I seldom use the clear filters, but have seen it before.
 
Air in the fuel system isn't like air in the brake system. So long as the carb bowls are full, the engine doesn't care.
 
just my 2 cents worth...I always thought the space you see in a clear filter when it is 3/4 full was filled with gas vapors and that way you always have a full filter. That way you still have a continues flow of gas while the car is running.
 
It is normal but defies logic to me.
It seems to me that the filter should be full of gas since the system is pressurized.
 
Thanks to all, it's nice to find out I don't have another mystery to solve. It's like getting a day off for free.
 
I would advise against using one of those MrGasket type clear filters. Its an accident waiting to happen. Glass tube sandwiched between two ends.... Glass breaks and you have a potential for a fireball.

81XHXD9edWS._AC_SL1500_.jpg
 
This is 1st time I've ever used a clear plastic filter and I have used it for a couple of years now. I got it so I can see how much crap has accumulated. From the beginning I noticed their was air in the filter but the engine seemed to run ok. Is it normal to observe this condition or is this a problem? Thanks

IMO....
The void space you see is actually fuel vapor not air. In the OEM fuel system used on the Hemi and Six Barrel engines, use a "fuel vapor seperator" to insure that the carbs receive only liquid.
BOB RENTON
 
If the fuel filter was mounted straight up and down, I don't think you could have that air gap. Mounted at an angle , I think you would have air trapped in the corner. ........................MO
 
I would advise against using one of those MrGasket type clear filters. Its an accident waiting to happen. Glass tube sandwiched between two ends.... Glass breaks and you have a potential for a fireball.

View attachment 1022279
I've used these for years on several cars with zero problems.
 
On my '70's bracket racer, I had two see-through plastic filters on my Holley double pumper (dual feed-two float bowels) and noticed them only half-full.

At the drag strip, I filled my aluminum fuel can (it was not insulated like the new ones sold today) with dry ice and the vapor/air was eliminated in the fuel filters. The dry ice was expensive and a pain to purchase, so I went to using plain ice after that time. With the regular ice, the vapor in the filters was also eliminated.

When cruising Main St. on Friday nights in the bracket racer without any ice in the cool can, I don't remember the status of the fuel filters while driving on the street after have had used ice a few days previous to that.

cool can.jpeg 65 Valiant  moter head on shot.jpg cool can 2.jpeg
 
A carbed fuel system pressure is probably around 6 psi but the reid vapor pressure of the fuel is 7 psi or greater depending on winter/summer grade and temperature.
 
It is normal but defies logic to me.
It seems to me that the filter should be full of gas since the system is pressurized.
It's pressurized between the pump and the bowls....

I said potential fireball... I have seen one break but that's one too many.
What caused it to break? Was it laying against something? I too have used them on cars that were having issues with trash but always made sure they were not against anything and didn't have any stress on them from the fuel line.
 
It was in my neighbors silverado. I think it was tinking on the intake for a while and just broke. I replaced it with one of the metal can style ones and no problems there..
 
Those don't allow you to see when fuel is in the line. To me, that makes them worthless.
 
Those don't allow you to see when fuel is in the line. To me, that makes them worthless.
Well, if you are not getting gas you are not getting gas. Doesn't take a degree in rocket science to figure that out. You can choose those clearish plastic ones too. Personal preference I use something that is meant to be durable. Glass is one thunk away from pumping fuel all over the place.. Your choice, no big deal.
 
This is 1st time I've ever used a clear plastic filter and I have used it for a couple of years now. I got it so I can see how much crap has accumulated. From the beginning I noticed their was air in the filter but the engine seemed to run ok. Is it normal to observe this condition or is this a problem? Thanks
It is very normal as the filter is NEVER filled solid with liquid.
 
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