Fuel Return

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Professor Fate

Push the button, Max...
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I'm about to break out the BFH and start swingin' at things...
'66 Dart wagon with a 360/904. Nothing wild, cruiser/road trip car. It's been on the road already, but I'm making a few changes in things because, well, I wanted to.
Basic story:
Pulled the tank (2 years old) to add a return line, and add the 3 nipple fuel filter to feed back to it. New standard mechanical fuel pump. Nothing fancy, I've done this with several cars in the past with no issues. Just hoping to alleviate potential fuel issues in the notoriously hot confines of the cramped early A engine bay.
Primed the line (with a hand suction pump) to get the fuel up to the TQ to minimize cranking on the thing. Give it a couple dribbles of fuel in the carb, and it fires right off. Repeat several times. Should have pushed fuel into the bowls long ago... Check the accelerator pump, it's dry- no fuel in the carb. Pull the line, lots of fuel at the inlet, nothing in the bowls. No, it's not the float settings. This was a running carb a week ago, and I can easily blow into the inlet without restriction.
Put a gauge on the fuel pump, 6# pressure plus a hair. Plenty of flow. Hook it all back up, and try to fire it up again. Won't fill the carb.
On a lark, I pinched the return hose from the fuel filter closed with a little vice grip. Badda bing, Badda boom. Fires up and settles into a nice idle. Pop the vice grip off the line, and it dies in a minute or three. Put it back on, and it's fine.
WTF? It shouldn't be feeding all that fuel back through the return line- after all, technically it's just a vapor return, not a full-fledged fuel return. Mebbe the filter is effed up inside (Wix 33054, now proudly being produced offshore), so I grab another filter off the shelf (this time a Fram G3499), and the same dad burn thing happens.
What gives?? Yes, I know the filter has to be oriented correctly, it's vertical with the vapor return nipple on the upper half. I've never had an issue like this before with this filter setup. I walked away for the day and will sleep on it, but in the meantime maybe somebody can shine a light on this for me- I wouldn't doubt that I 'm overlooking something really stupid. Wouldn't be the first time.
TIA
 
Sounds like it may need a better pump, Pressure does not equate to Flow. GPH. I have had this happen and replaced the pump with one from NAPA, Get one for a 86 87 carbureted dodge truck .They came with a return style filter.
 
Update-
Tentative success!
Spent more time than I wanted to searching manuals and the Interweb and wading through mounds of irrelevant information, and came up with this.
In the '75 FSM, I have this:
1723497308811.png

So, the filter's vapor return is supposed to have a .060 orifice/restrictor. No sign of it in the Wix.
Found a couple old threads on the B and E body sites, seems even then there were issues with some filters coming through with oversized or no restrictors, QC was a problem or the filter lineups were being homogenized or whatever, and it was causing issues ranging from fuel delivery to lean idle misfires.
As a temporary test of what I think I found, I took a scrap of 1/4" hard line and drove a piece of lead shot into one end.
1723497892347.png

Then, using a drift punch inserted into each end of the line, I hammered the lead in place so it was solidly in place and wouldn't move.
1723498063017.png

Then I drilled the correct size orifice in the lead plug.
1723498238179.png

I installed my makeshift orifice in the return line coming off of the filter.
Fired up the engine- issue is gone.
I'll come up with something a little cleaner for a permanent fix, I'm thinking a 1/4" brass connector barb either soldered closed and drilled, or maybe tap it's inside diameter for an appropriately sized carb jet...
This way I won't have to worry about whether the filter I get has the proper restrictor or not- if it doesn't, I'm still good to go. If it does, then my added restrictor just becomes redundant and doesn't hurt anything.
Maybe this can help someone else who's about ready to throw a match in the gas tank and walk away.
 
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