In-tank Fuel Pump, '78 Continental Coupe

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JimA
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In-tank Fuel Pump, '78 Continental Coupe

Post by JimA »

After trying MANY things (plastic carb spacer, under-carb heat shield, Insulation on fuel lines, pump and regulator, new fan clutch, rear-mounted electric fuel pump and header wrap and insulating tape on the tail pipe near the pump and tank), and STILL seeing fuel vaporization issues I bit the bullet and installed an in-tank fuel pump and by-pass regulator. The car has a 180* thermostat, 7-blade fan, fan shroud and dual cold air intakes. Even with all that, fuel would vaporize and bubble in a pre-carb transparent fuel filter and, apparently, in the rear-mounted electric fuel pump and engine-mounted mechanical pump since pressure would be erratic and it would start hard and stall after sitting hot for 10 minutes.

Others have solved vaporization issues with some of the things I tried (before biting the bullet) but none worked for me.

I'm documenting how I installed the in-tank pump for info but anyone contemplating doing that has to assess the hazards of putting electricity in a fuel tank, and fuel injection pressure in a carburetor system, for themselves. Choose your own installation and proceed at your own risk.

Having said that, here are some of the things I was concerned about and how I approached the install:

. Bare terminals and wires in gasoline and gasoline vapors. This is apparently not an issue since standard in-tank components have lots of bare conductors. Gasoline and vapors must not be conducting at the voltages seen for fuel pumps and gauge sensors.

. In-tank hoses, wire insulation, connectors, and shrink wrap that are rated for submersion in gasoline. I used only components that came in parts and kits intended for use in tanks.

. No sparks in the fuel tank. Just for extra level of safety, I sleeved the positive wire for the pump in 1/4" hose rated for submersion in gasoline. Also made sure there were no sharp edges on the bracket and extensions that might damage insulation on wires.

. No overheated wires in the fuel tank. My installation used short lengths of wire intended for the fuel gauge sender to power the pump. Best advice I got was that wire should be adequate and not a problem.

. The instructions for the Walbro pump say it is NOT to be used with carburetors. I used a by-pass regulator with 3/8" aluminum tubing for the return line. Also used fuel injection rubber hose rated for 100 PSI rather than carb-rated hoses. Non-barbed connections, i.e., where a hose goes on the end of a hard tube. were double-clamped with fuel injection clamps. I don't want a hose coming off the end of a hard line and spraying gas. Some barbed connections have only one fuel injection clamp.

This project was used as a starting point. http://www.65fastbackrestomod.com/2011/ ... art-2.html Used the same '93 Mustang fuel pump/sender mount and the Walbro GSS307 pump. That poster hadn't worked out the fuel gauge sender yet. I used an aftermarket fuel gauge sending unit, Classic Instruments SN39 http://www.summitracing.com/parts/cin-sn39 That sender has the right ohms (75-10) for the pre-'89 Ford fuel gauges and works OK with the '78 Continental. It goes in the top of the tank and was configured for the 15 1/2" deep tank.

The fuel pump bracket used is intended to be top-mounted in a shallower Mustang tank.
IMG_1559.JPG
The top and bottom parts of the bracket are secured with four screws. Removing the screws, flipping the bottom part around and attaching the bottom part using only two screws thru the lower holes in the top part and the upper holes in the bottom part provided a starting point for a side-mounted bracket to replace the original sender and pickup bracket.
IMG_1560.JPG
A test fit of the 90* bracket placed the pump about 2" too high in the tank. A cardboard pattern was cut for extensions that would place the pump 2" lower and two extensions were cut from 10 gauge steel.
IMG_1569.JPG
The extensions were curved for strength and easier fit thru the tank hole and painted with POR 15 tank sealer. Given how TREATED metal corrodes in the tank, I didn't want to put bare steel in the tank. With the extensions in place, a picture thru the filler tube hole shows the pump at a good depth.
IMG_1570.JPG
A bracket was made from 1/8X3" steel to mount the bypass regulator. It is a companion, and tacked to the coil bracket and mounts by the same bolt in the intake manifold.
IMG_1517.JPG
A 3/8" aluminum return line follows the supply line back to the tank. It had to be made in several sections to snake thru the front and rear torque boxes and over the rear axle. Again, all 100 PSI fuel injection hose in the joints and all connections double clamped with fuel injection clamps. Flared fitting would have been better. It would have been LOTS simpler to install the regulator back by the tank but I'm taking every step to get COOL fuel to the engine.

A problem occurred when the system was tested. With the regulator adjusted all the way out, pressure at the carb was 11+ PSI. The 1/4" tube for the return on the Mustang bracket and a rubber nozzle on the open end in the tank was restricting the return too much and not allowing pressure to be regulated down to 6 PSI. The Quick Fuel carb didn't seem to mind other than the levels in the bowls were too high. Engine ran fine with no evidence of flooding. QF instructions recommend 6-6.5 PSI and say that higher pressure will cause higher levels; lower pressure will cause lower levels. The floats had to be readjusted for the higher pressure.

Removing the rubber nozzle inside the tank on the return line got the pressure down to about 9 PSI which I think is OK for that carb. Maybe not for yours. I'm quite sure that a 3/8 return line into the tank would allow for lower pressure at the carb.

A hole was cut in the top of the tank to insert the sender. This hole saw http://www.amazon.com/gp/product/B0054S ... ge_o01_s00 makes the right sized hole. The gasket in the sender kit was used to mark for the hole and screw holes. The top of the tank is pretty flat beside the vent valve.
IMG_1581.JPG
#10 metal screws were used rather than the supplied #10 threaded screws. Seemed like a split ring with captured nuts could have been used with the threaded screws but none was supplied in the kit. I chose to not use the rubber gasket from the kit but rather to use some gasoline tolerant sealer. http://www.amazon.com/gp/product/B007VI ... ge_o00_s01 Since the area wasn't perfectly flat, I wanted to use sealer but couldn't be sure that the sealer would be compatible with the gasket.
IMG_1582.JPG
Be sure to vacuum out ALL the metal bits created by the hole saw. You can shine a light in the vent valve hole, look in the filler tube hole, and vacuum from the new hole.
IMG_1583.JPG
The trunk floor is raised above the vent valve and the raised area is large enough to accommodate the added sender and wires. I checked it with Silly Putty. I also stuck some 1/4" rubber mat on top of the tank with 3M spray adhesive. Wanted a little extra clearance for the sender wires and hoped the rubber might cushion out some pump noise.
IMG_1588.JPG
That pump is quite noisy, but not noticeable with the engine running in my car. Might be annoying with a stock exhaust system.
1978 Continental Coupe
521 Stroker -- SOLD :-(
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JimA
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Re: In-tank Fuel Pump, '78 Continental Coupe

Post by JimA »

When the tank was filled above the filler tube, there was some seepage around the filler tube grommet. Found an new grommet that fits, even though the applications listed for it don't include any Lincolns. http://www.fillernecksupply.com/1966-19 ... -e1az9072/ If you're pulling the tank for any reason, I think its a good idea to replace it. Would have done that in the beginning but wasn't finding one for the '78 Continental. I used a little of the fuel-tolerant Permatex sealer around the outside of the grommet to compensate for imperfect 38 year old metal. The filler tube wouldn't slide in the grommet without a little oil on it.

The pump is much quieter, and not objectionable, when there's more fuel in the tank.
1978 Continental Coupe
521 Stroker -- SOLD :-(
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Dan Szwarc
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Re: In-tank Fuel Pump, '78 Continental Coupe

Post by Dan Szwarc »

For used the same filler neck seal on just about all Lincolns and full-size fords from 1970 to 1989. The PN was updated in 1982. The seals are still available new from dealers and Ford outlets.

I bought one for my 70 Mercury from the bay of E for about $18 a few years ago. Now, they are around $25.
User avatar
JimA
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Re: In-tank Fuel Pump, '78 Continental Coupe

Post by JimA »

Just reread this thread and noticed that the inertia switch wasn't mentioned. It was installed in the trunk to turn the pump off in a collision. In another installation I used a low oil pressure switch to stop the pump when the engine isn't running.
1978 Continental Coupe
521 Stroker -- SOLD :-(
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