I recently completed a ford gas engine conversion to 24 valve cummins diesel on my 1990 f250 and was curious as to if anyone has modified their gasoline filler necks in a way to except not only the larger diesel fuel pump nozzles but also higher flow and volume. I removed the restrictor plates from each filler head and plasma cut larger holes to except the bigger nozzles but I can only trickle the fuel into the tank. If I flow on high or even medium rates it clicks off the pump. The only way for me to fill the tanks is to stand there and hold the nozzle away from filler head and and slowly fill the tank, if I flow to much it foams up and spills out of the head. I dont want to have to find a set of diesel filler necks and hoses for my ford if I can somehow modify the ones I already have to work properly. If someone has somehow done this mod to work please enlighten me. If I have to find proper filler necks I will do so though. The ford filler head necks down to an inner 1" hose that drops directly into the tank. Just before the small hose connects there is six 1/4" holes that feed into the large 2" filler hose. I am guessing the small hose is for main fill and the outer hose is for fill venting? I was thinking about cutting the inner hose out all together. Just wanted some input before I do a bunch of mods to it just to find out it dont work

 

mine does that too. i have an 85 6.9 it's frustrating as hell. there's gotta be a way to fix this. how'd you cut the bigger holes?

 

I removed both filler necks and plasma torched the small filler hole into a larger one. In the process of torching the filler hole larger I ended up removing the small spring loaded restrictors that are behind the small hole and hinge out when you pump fuel and cover the fill hole when not in use.

 

did takin the restrictor out help? or did you do that before

 

I did the cummins conversion and went to fill my truck at the gas station with diesel to find out I forgot that most diesel pump nozzles are larger then the gas pumps. I prepaid for $100 of diesel fuel and had to leave the station and get a funnel to fit into the filler hole to start filling up. It kept foaming out if I ran the pump too fast. So it took me about 25 minutes to dump 30 gallons of fuel into my truck. After fueling up I went to my shop and removed both filler necks and plasma torched the original 1" holes with restrictors to about 1-7/8 holes there by removing the spring loaded restrictors in the process. I then drove the truck for a few days to burn some fuel off and threw 9 bucks in it today to find out I can put the big diesel pump head into my modified filler head but still have foaming and fuel spilling out if I run the pump to fast.

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so far nothing has helped

 

I forgot how much the orignal diesel pick-ups sucked to fill,I think the problem stems from the way diesel foams when pumped.I dont know if its possible to retrofit with parts from an 85 or later model year (thats when I noticed the factory fix).Reworking the gasser parts may be futile,if the factory fixes started from the tank opening up.In other words it may not get much better unless you change the tank.If changing tanks is necessary I would concider after market like Titan tank co.