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Fuel tank vent lines...etc.  Rating:  Rating
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 Posted: 04-23-2009 04:56 am
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dixiedog
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Hi, I'm kinda new to this board so please bear with me... putting my JH back together now and I have the dreaded Jorge fuel tank, didn't leak when I filled it with fuel out of the car, and after looking at every picture I could find I see no one has put the anti-syphon line off the "T" from the fuel pump to the tank pressure relief valve. Do I need it ?  Thanks.

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 Posted: 04-23-2009 05:04 am
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JodyKerr
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Take a look at the following: http://www.theymightberacing.com/Projects/FrameOff/JH74G/FuelSystem.aspx

I have a Jorge tank and have tested it it pressure wise. I put the tubing in as was described in the parts catalog & manuals. I've not completely decided it'll work as is, but that adjustable once the car is running. I asked about specialty anti-syphon t's, but didn't get any real response.

Jody

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 Posted: 04-24-2009 03:00 am
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Gary Martin JH 15371
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I just finished installing my Aluminum tank, also by Jorge, in to my JH. I hooked it up as Jody explains, except I did not install the anti-syphon line with T section. My setup comes from the tank to a filter, then to the pump, then to a pressure regulator (more about that in a min), then to the fuel line to the carbs. The larger line on top of the tank connected to the brass pressure valve runs down the right side of the tank, through a hole and vents out under the car. This leaves the two pipe stubs on the top of the tank, one small and one larger. On my car I used the larger pipe stub for the line to the charcoal canister. As Jody explains there is a special rubber hose that adapts the larger 3/8 pipe stub to the 3/16 line for the canister. I could not get my hose adaptor to go on, since the pipe stub bulges out to 1/2 in at the end, so I cut that bit off. Then went on fine. The smaller pipe stub is most likely for this anti-syphon system which I did not put on. I capped of the small pipe stub. I don't see how Jodys return setup works, since it seems using a T would just pump gas right back to the tank and not supply enough pressure to the carbs. It seems there should be some sort of restrictor on the anti-syphon line back to the tank.  Strombergs only need about 2.5 or 3 PSI. I think my pump was putting out a bit more than this, causing the car to run rich, so I installed the fuel regulator which seems to have helped.

Also the Jorge tank comes with a thick plastic ring to use in place of the stock rubber seal. Do not see how in the heck that would ever seal. I used the stock rubber seal, but the fit is loose when installed. So what I did was take an extra locking ring for sending unit, and grind off the tabs and lip. Then used it as a shim under the lock ring to give more pressure to the seal. So far so good, but I have not filled up the tank that far yet.

Gary

Last edited on 04-24-2009 03:09 am by Gary Martin JH 15371

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 Posted: 04-24-2009 12:27 pm
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Jim Ketcham
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This has been covered somewhere on this board before.

The original line from the T to the tank has a one-way check valve in it.  It is actually hidden in the line itself, so often it is thrown away when someone replaces that line.  Check valves were common on that era car and can be found and adapted if you lost yours.

Anti-syphon is needed only when a vehicle's tank fuel level is above the carbs and the head is enough to force the carb needle valve off of its seat.  While not common, it has happened.

Jim

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 Posted: 04-24-2009 05:05 pm
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JodyKerr
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Jim,

 

Do you have any idea of a part number for the check valve? It's not noted in any of the Jensen-Healey reading materials I have around. As to the two fittings on the top of the tank, the smaller diameter one is for the emissions line and the larger intended for the anti-syphon line.

This was one of those scenarios where I knew there was something "missing" for the documentation, but without evidence from someone else I wasn't able to do anything about it.

 

Jody

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 Posted: 04-24-2009 05:30 pm
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Jim Ketcham
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Hello Jody,

Unfortunately, for the JH, the actual valve was part of the "anti-syphon hose assy" p/n 97183 for later models.

Earlier models had it as an interim service modification (I guess anti-syphon was not originally on the JH) and called it P/N 94102 "pipe assy (includes tee piece, one-way valve...).  I infer this from the parts manual.

I can attest to the fact that the valve is hidden in the later models as I have cut them out of the hoses and installed them in new hose for several cars.  If you can't get the original, you can find anti-syphon check valves used on other cars that splice in.

Hope this helps,

Jim

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 Posted: 04-25-2009 08:22 pm
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JHRV8
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Upon reading the Jensen of England internet site, I read that the antisiphon valve is a must as when you park the car with the nose down on a steep slope, you can get run-off of the fuel into the carbs and massive flooding and subsiquent fire hazzard, so I believe the anti-siphon  valve or another that works the same is a must......regards, JHRV8

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 Posted: 05-07-2009 06:06 pm
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JodyKerr
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Jim,

 

Thanks for the information. I went spelunking through my array of spare JH bits and found an old line with the Check valve in place. I've cut it out of the old line and will end up updating my article on the subject.

In addition, since I'm at the local NAPA on a regular basis I'll check their books to find a replacement part that matches.

Jody

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