Hey again,

Got that '74 rebuilt 225 Slant w/Supersix intake/carb setup in the truck and mated up to the 727 I overhauled nicely. Runs very well but there is a problem that has me stumped.

Ran it in a couple times and when I was looking it over to see that there were no leaks I heard a drip sound. Well, after crawling over, under and around the motor I learned that fuel was steadily going thru the carb and into the Intake. Mind you the engine was not running.

Dumped the oil quick and flushed the motor. Figured I messed up bad on the carb somehow so off it came, stripped it and into the dip with the body while I cleaned all the parts and overhauled it again.

Ran it in and again it did the same thing. Mechanical fuel pump by the way. Lean-burn ignition if that makes a difference. I just don't understand this.

What am I missing here?

The fuel return line to the tank is fine. Checked it twice. Fuel filter is new (and I replaced it a second time just to be sure). The fuel like and return line are different sizes so no chance of problems there.

** An additional search of the board tells me that you can also leak fuel into the motor from the fuel pump? Could this be the dribble I am hearing and is it possible that this could happen with the motor off? **

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Lead, Follow Or Get The Hell Out Of The Way!

A leaky fuel pump diaphragm is a probability, and yes, it can fill the crank case when the engine is not running.

The orientation of the diaphragm above the attachment point of the pump makes it very likely.

When you remove the pump you will likely note evidence of fuel having run from the diaphragm to the attachment point on the pump.

It happened to me, and a NAPA fuel pump in the $20 range cleared things right up.

Give it a shot,

Scott

I have also "heard" of New off the shelf pumps being bad, so dont discout the pump even if its new.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

On the way to the parts store now. thanks

_________________
Lead, Follow Or Get The Hell Out Of The Way!

It's always possible to have a faulty fuel pump, but if you are seeing fuel dripping out the carb nozzles and into the intake with the engine shut down, it is not because the fuel pump diaphragm is faulty. That introduces fuel directly into the crankcase through the fuel pump body, and you didn't mention a grossly overfull crankcase with oil that smells of gasoline. The symptoms you describe are likely occurring because the carburetor is percolating (not sufficiently heat-insulated) and/or the float level is set too high, and/or the metal line from the fuel pump to the carb is boiling. The fix for that last problem is the fuel line mod.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Overnight it filled the crankcase with gasoline so I am pretty sure it was the fuel pump. Something else I saw when I was inside the motor makes sense now too. The cam was discolored at the lobe where the fuel-pump lever engaged it. I should have gotten a new pump the first time around. Lesson learned... I am waiting for 6pm to roll around so I can go to the parts store and get the replacement pump.

On the fuel-line mod, I already relocated it. The fuel line goes up at an angle toward the alternator where the fuel filter is now mounted. There another fuel line continues on to the carb and of course the return lines goes back down. This places it behind the alternator though not very close. I did this out of expediency when I assembled it since I have a lot of braided steel and fuel line tubing on hand anyway. This arrangement allows me to "purge" the fuel line with less mess if I am working under the hood.

I am familiar with vapor-lock and fuel-line boil-off and had not considered this since the engine only ran for a short time with the hood up while I was inspecting my work. though I am sure it can cause the aforementioned problems.

I will confess I have incorporated a good many mods from this board in the Slant and the 727 coupled behind it, mainly focused on improving reliability. Opened up the main and rod bearing oiling holes with a Dremel to match the oil gallery. Used the tops from two sets to further enhance oiling. Beveled the forged crank oiling holes at the main and rod journals for improved oiling and had it turned. Drilled the plug with a .020 hole at the timing chain to enhance oiling there. The cam was "spot on" all around so mic'd it out, replaced the bearings and left it alone. Replaced the valve seals. Had the intake/exhaust manifolds separated, milled, reassembled and milled the intake/exhaust mating faces and replaced the bolts with studs. Front and rear main seals. Freeze plugs. Installed a newer model 318 starter which spins the motor much faster. Replaced the spark-plug tube rings. Had to heli-coil two of the power steering pump bracket mounts holes since they were stripped out. Pushrods and lifters were good so a good cleaning was all they needed. No compression loss on any of the cylinders and they all looked great from the bottom when I did the crank so no real intense work on the head. New water pump and thermostat. Replaced the original alternator with a 100 amp GM style three wire unit that pretty much mounted right up. Scrounged up an original fan shroud since it was missing when I got the truck. Replaced the fan with one that was not beat up.

Scrounged in the U-Pull-It for pulleys until I had double belts on everything except the power steering and I am still working on that. Snaked and brushed every oil and water gallery in the block before the new plugs went in it. Spent over an hour with the pressure washer cleaning it when I had it torn down and on the stand. Soaked the block with so much CLP to get the water out that it will be smelling like bananas for months.

New metal timing chain and gears (I ended up with one of the cam timing gears with the crank dot to the inside and the cam dot to the outside and I hate that so I counted out the teeth and used my drill press to lightly cut a double-dot opposing it since I had the problem of getting it backward once before and had to time the motor on #6 cylinder). Carter BBD carb that is completely rebuilt to specs (checked the float about 10 times). No wear on the distributor gear but I replaced the pickup unit since I had the distributor in my hand at the time. Discovered the valve cover was bent and twisted with a few deep gouges on the sealing surface along it's length when I put a straight edge to it, so off I went again to the U-Pull-It with my straight edge to find a good replacement. New grommets for it on the way home.

Non-lockup 727 Transmission has new springs, bands and clutches, bushings and bearings. Replaced the Sungear with the suggested replacement. Can not properly recall at the moment except that mine had a crack by one of the pins and a slightly different one was suggested. Drilled additional lubrication ports in the shaft for enhanced lubrication. Valve body completely rebuilt for heavy duty performance. In another post I mentioned that a limit tang had been broken off the throttle kickdown lever on the valve body. I replaced that. All new seals. Replaced the torgue convetorqueChecked the vent in the top front of the bellhousing and no problems there plus I ain't too hot on the idea of drilling into the case for a second vent when the original has done fine this long. New speedo gear since the original one was partially stripped (it was loose when I first got the tranny so that explains that). Added a transmission cooler since I had the kit sitting around for about 10 years taking up space. Replaced the transmission pan with a OEM stock unit since the original was dinged up pretty bad.

Painted everything on the engine and transmission black or red to suit me. I'm a stickler for clean equipment since it makes it a lot easier to detect leaks. Mounted looms for all lines, hoses and wires so nothing moves around. Pressure washed then windex'd the engine compartment while the motor and tranny was out. Replaced the steering coupler and flexplate. Painted the steering unit. Two matching Delco batteries on either side. Real oil pressure unit coupled to the block so I get the real scoop on lubrication.

Lots more that I can not properly recall at the moment since I am getting hungry and it is almost time to get the pump. Thanks a million. I will post the results as soon as I have them.
Cheers!

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Lead, Follow Or Get The Hell Out Of The Way!