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The stock fuel filter has an extra nipple to connect a vent line from the filter back to the tank.
That's great if you use the stock filter.
I do not plan to use that style fuel filter, opting for an inline clear glass filter with a element that can be changed or reused.
How would I plumb the vent line back to the tank with a fuel filter that does not have a provision for the vent line?
Bryan Smith
Fort Wayne, Indiana
2017 Jeep Grand Cherokee Limited
- 75th Anniversary Edition - 1941 Trim Package - Recon Green --Daily Driver
1986 Jeep J20
- Super clean rig from the AZ/CA state line -- Current Project
1982 Jeep J10
- Has become a Long Term Project.
1981 Jeep J20
- Commercial flat bed - Lost in a Divorce --gone
1987 Jeep J20 Pioneer
- Former Rick Bielec aka Ricbee plow rig. Major rust!! --gone
Its not a vent, its the fuel return. without it the carb bowl would over flow since the pump is running all the time. You would do a clear filter before or after the stock one if you wanted.
No, I don't think the float bowl would overflow. The earlier engines without the return don't have that problem. I believe that the return was added only to keep the fuel cooler, by circulation from the tank to the engine and back. You could plug the return and it would not affect engine operation, except in terms of vapor lock.
I agree that you could add the clear filter ahead of the factory filter. The added restriction of an additional filter should not matter.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
There is not a lot of pressure on the inlet valve of the bowl, just what the float pushes against it. ~6 psi of the mech pump could over come that I'd think.
That makes sense intuitively, but I don't think there is any difference between the float valves and fuel pumps of the 70-ish engines without a fuel return line, and the later engines that have one. These earlier engines have no problems with float bowl flooding. 6 psi sounds like a lot, but the float pressure is concentrated on a very small area of the needle. Say the seat area is 1/10" in diameter, then the pressure exerted by 6 psi is about 1/4 oz. Seems pretty reasonable for the upward float pressure.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
Well Mr. Smith, looks like you're in a perfect position to put this to rest! Since the glass filters are only what, $12 for the name brand Holley ones? You could install it with the return line intact but unused and see what happens!
Personally, when I tried it years ago I had to many other issues with the stock carb to know if it did anything. When I installed the Holley 4bbl, I set it up with a return line.
79 J-10 (Honcho Mucho) KE0LSU
304/Performance Fuel Injection TBI/MTA1/SP2P/Magnum rockers
T18/D20/D44s&4.10s/33" Mud Claws
Grizzly Locker Rear
4" front spring drop, 5" rear shackle flip
Chevy style HEI (ECM controlled)
Dolphin "Shark" gauges in a fancy homemade oak bezel
3/4 resto, rotting faster than I've been fixing it.
Charles Kline wrote:Ok, but what are you doing with your tank vent or your carb bowl vent? Its literately just sitting there absorbing fuel vapor, hurts nothing. Sure it can be a vac leak if its got a bad diaphragm or bad hoses but its not the HP robber some folks worry it is.
Good point
Bryan Smith
Fort Wayne, Indiana
2017 Jeep Grand Cherokee Limited
- 75th Anniversary Edition - 1941 Trim Package - Recon Green --Daily Driver
1986 Jeep J20
- Super clean rig from the AZ/CA state line -- Current Project
1982 Jeep J10
- Has become a Long Term Project.
1981 Jeep J20
- Commercial flat bed - Lost in a Divorce --gone
1987 Jeep J20 Pioneer
- Former Rick Bielec aka Ricbee plow rig. Major rust!! --gone
Another case of "Yes, I need the Fuel Return Line" and I will have one.
As been suggested, I will install the stock filter with the return line.
Next, I will install the the glass filter between the stock filter and the carb.
Bryan Smith
Fort Wayne, Indiana
2017 Jeep Grand Cherokee Limited
- 75th Anniversary Edition - 1941 Trim Package - Recon Green --Daily Driver
1986 Jeep J20
- Super clean rig from the AZ/CA state line -- Current Project
1982 Jeep J10
- Has become a Long Term Project.
1981 Jeep J20
- Commercial flat bed - Lost in a Divorce --gone
1987 Jeep J20 Pioneer
- Former Rick Bielec aka Ricbee plow rig. Major rust!! --gone
[quote="tgreese"]I believe that the return was added only to keep the fuel cooler, by circulation from the tank to the engine and back. You could plug the return and it would not affect engine operation, except in terms of vapor lock.
That makes sense, these SJ's were plagued by vapor-lock, weren't they? I've heard vapor-lock horror stories about them for years.
The vent return port on the filter is to help reduce vapor lock by having boiled fuel vapors bled off and sent back to the tank while still allowing liquid fuel to reach the carb. The vent return port must be positioned at the 12-o'clock position in order to be effective.
I use the stock fuel filter and run a glass pre-filter before my mechanical pump.
-Jonny B.
1979 Cherokee Golden Eagle - UNDER CONSTRUCTION
7" lift, 35x12.5x15
AMC 401 - Pro-FLo 4 FI
NV4500/NWFBB/NP205 - Triple Stick'd
F D44 - 4.10, Eaton E-Locker
R M23 - 4.10, Detroit Locker
1979 Cherokee Chief - Parts
1979 Cherokee Chief - Parts
1979 Wagoneer - Sold
1981 Cherokee Chief - Cubed
az chip wrote:If I put my fuel return at 11:30, can I still post here?
If we let you do it then someone will want theirs at 10:30, then someone else will want theirs at 9, then 3...then what's next? Anarchy?!
This isn't Nam, there are rules! Has the whole world gone crazy?! Am I the only one around here that gives a **** about the rules?!
I'm joking, of course
-Jonny B.
1979 Cherokee Golden Eagle - UNDER CONSTRUCTION
7" lift, 35x12.5x15
AMC 401 - Pro-FLo 4 FI
NV4500/NWFBB/NP205 - Triple Stick'd
F D44 - 4.10, Eaton E-Locker
R M23 - 4.10, Detroit Locker
1979 Cherokee Chief - Parts
1979 Cherokee Chief - Parts
1979 Wagoneer - Sold
1981 Cherokee Chief - Cubed
The PIG Smith wrote:Another case of "Yes, I need the Fuel Return Line" and I will have one.
As been suggested, I will install the stock filter with the return line.
Next, I will install the the glass filter between the stock filter and the carb.
Wally has the clear glass filter installed before the stock filter.
I had a trip to Moab in April 2012 and spent the day out on Steel Bender trail. It was pretty bouncy day and by noon I had fuel problems. By 2pm it was in the mid 80s and I had a lawn sprinkler spraying fuel out of the carb. We replaced the needle and seats on the Holley 600 but they didn't last long. I came home the next morning and skipped the next 2 days of rides. Turns out the factory return was clogged in the section of steel tube. I changed the line completely with a rubber line.