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Anyone ever put foam in their fuel tank?

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Mark W. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Topic: Anyone ever put foam in their fuel tank?
    Posted: 12 Sep. 2021 at 9:22pm
I been thinking about the problem of fuel sloshing out of the filler neck when going around a right hand turn after filling the tank.

And I got to thinking about the foam that is put in race car fuel tanks to stop sloshing and as a safety to keep fuel from splashing in a wreck.

And I wondered if a person put a cylinder of this foam in the filler neck would help keep fuel from sloshing out. I have figured out a way to hold it in place and make it easily removable for refueling. As it would drain out of the foam as the tank level goes down barring it retaining fuel when it is pulled out (making a mess) I think it would have to help.

Soon as I come up with a couple other things to add to my next Summit racing order to spread the cost of shipping I'm going to try it.

Oh and I should say I have a Vintage Stant Locking gas cap on CHUG so its vented no matter what LOL.
Chug A Lug
1948 2A Body Customized
1949 3A W/S
1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nofender Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep. 2021 at 5:08am
I don't have any first hand experience. But I've heard nightmares. Over time the foam starts to break down and clog up fuel systems. Make up of the foam may have changed over the years and eliminated that issue. But I always avoided foam for that reason. 

These are pricey - but in my opinion do a mush better job! baffle balls. 



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Downs Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep. 2021 at 8:06am
When I still worked on helicopters and airplanes for the Marine Corps fuel foam was a common thing.  Helped with sloshing and helped keep the fuel from atomizing in an accident or combat damage, reducing fire risk.  Came in blocks and had to get installed in the tanks like a puzzle lol. 
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Mark W. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep. 2021 at 9:10am
The baffle balls would not work unless they were available in a different size as the tank is only 6" deep the balls shown are 7.5"

The foam I am looking at is rated for E85 fuel and like many other things would need to be replaced before any desegregation happens. I this case about every two years is recommended. And I wouldn't be filling the tank only placing a short cylinder of the foam in the filler neck.
Chug A Lug
1948 2A Body Customized
1949 3A W/S
1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep. 2021 at 9:42am
I don’t see that foam will cure the problem. That will only slow down the leakage.
The real problem is that a full tank will drip out the neck anytime and every time the Jeep is positioned with the neck downhill.
Even if you have a tight fitted cap it will seep out the neck  if parked downhill long enough. That will surely eat at the paint on the drivers side of Jeep if it is not 2K.
Obviously having a tank cap with a poor gasket only increases the speed at which it leaks.
The only solution
Is to fully seal the cap on the neck with a non vented cap or a remotely vented cap (vented via long hose) 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote drm101 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep. 2021 at 1:11pm
I had a problem with fuel spilling out and found that replacing the rubber gasket and bending the tabs on the cap took care of it. It seals up fine now. My only issue is that after running for an hour or so the tank will be in a vacuum and pop when the tank collapses slightly. No problems with the way it runs or anything, it just scares me sometimes when it pops. After reading the manual I realized that the valve on the cap works to hold a small vacuum, and also release pressure. 
It says the pressure valve opens at 1 1/2 to 2 1/2 psi, and vacuum valve opens at 3/4 psi. 




Edited by drm101 - 14 Sep. 2021 at 1:24pm
Dean
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Post Options Post Options   Thanks (0) Thanks(0)   Quote outlw21 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep. 2021 at 11:21pm
what are you going to do with the fuel sender float?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 22 hours 9 minutes ago at 8:03am
Not that the sender unit is in the FUEL FILLER NECK. But that wouldn't matter as the sender unit I am using does not use a float or any other moving parts.
Chug A Lug
1948 2A Body Customized
1949 3A W/S
1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jeeper50 Quote  Post ReplyReply Direct Link To This Post Posted: 15 hours 7 minutes ago at 3:05pm
Put some in and report your findings, I'm kinda curious to find out
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 6 hours 45 minutes ago at 11:27pm
Originally posted by drm101 drm101 wrote:

I had a problem with fuel spilling out and found that replacing the rubber gasket and bending the tabs on the cap took care of it. It seals up fine now.  . . . After reading the manual I realized that the valve on the cap works to hold a small vacuum, and also release pressure. 
It says the pressure valve opens at 1 1/2 to 2 1/2 psi, and vacuum valve opens at 3/4 psi. 

I think my '46 has original cap.  Fuel spillage has never been an issue while moving.  It did start leaking several years ago when parked off-camber,  full tank,  driver-side down.  . . .  but after replacing the gasket it is back to "almost" never leaking.    

The only time it leaks is when the tank is full,  parked with driver side down,  (for a fairly long time),  and the temp rises significantly after parking.   (pressure must go above the 1.5/2.5 psi mentioned above)  

The stock cap design seems to work good,  but does not lock.   If locking is requirement,  then it will be interesting to see how the foam works on the road with that cap.    It does not seem that foam in the filler neck, would help  ->  if parked driver side off-camber,  full tank,  using a open vented cap.
 


Edited by JeepFever - 6 hours 37 minutes ago at 11:35pm
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