Fuel Delivery Questions

Tech tips and how to's

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v8_ranch
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Location: Jackson, TN
Model: 2000
Year: High Windshield-68-70

Fuel Delivery Questions

Post by v8_ranch »

Good day!

So, getting ready to assess my fuel delivery on my 68 2000. I haven't had a vehicle with a mechanical fuel pump in a while. I have the fuel line form the tank disconnected and stuck about a 2 foot length of fuel line into a small gas can. Have the outlet hose disconnected from the carb inlet and into a pan. Cranked for several seconds, and no gas.

My temporary gas can is basically sitting about the same height and right next to the battery. The suction line is coming up from pump and loops over into the can. My question - if the pump is in proper working order, does it have enough suction to pull from my temporary can, or does the tank need to be more at the level of the pump (I am assuming the tank is more at that level?)?
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Mackn367
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Re: Fuel Delivery Questions

Post by Mackn367 »

I've read you can turn engine over by hand a few times and bam gas come out.... this didn't happen with me... but I'm pretty sure my problem was actually more about not having the right pressure and fully submerged fuel lines.... I had to eventually siphon the fuel up into the fuel filter. Once I got it to that point it worked great and had a nice flow - maybe try this first to basically "prep" the fuel pump?

Edit - oh and I knew part of my problem was related to the line bc when I first began to siphon it as if I was sipping from a straw with a hole above the liquid. I then re tightened everything back down and then it was actually siphoning (like drinking from a straw fully submerged/fully sealed straw)
Nick
1967.5 Roadster 1600
VIN: SPL311-13038
Orange County, CA
v8_ranch
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Re: Fuel Delivery Questions

Post by v8_ranch »

Thanks Mack, I will try priming my inlet hose before getting too crazy with any other direction
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Linda
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Re: Fuel Delivery Questions

Post by Linda »

Good info on Rallye site about pumps
http://www.datsunroadster.com/PIC_PAGES ... 170-06.htm
Rebuild kit available from Rallye for early pumps. Some have rebuilt late pump.
Also SinCityDatsun has a rebuild kit too.
http://sincitydatsuns.com/store/c7/Fuel_and_Carbs.html
Your pump likely is toast if rubber is dry rotted and valves are old.
Linda
68 1600 Los Angeles, CA
New owners must read: the ultimate road trip, by Scott- roadsterroadtrip.com-http://www.roadsterroadtrip.com/index.php/readfromstart
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Mackn367
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Re: Fuel Delivery Questions

Post by Mackn367 »

Linda wrote: Fri Oct 16, 2020 1:20 pm Good info on Rallye site about pumps
http://www.datsunroadster.com/PIC_PAGES ... 170-06.htm
Rebuild kit available from Rallye for early pumps. Some have rebuilt late pump.
Also SinCityDatsun has a rebuild kit too.
Your pump likely is toast if rubber is dry rotted
Linda
+1 on this. Make sure you have a rebuildable fuel pump too. Post pics of your pump once you remove it from the engine and I'll let you know. It is extremely easy to rebuild the pump - as long as it is rebuildable. :)
Nick
1967.5 Roadster 1600
VIN: SPL311-13038
Orange County, CA
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Linda
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Re: Fuel Delivery Questions

Post by Linda »

I could not get pump off with the bolts used....had to jack car up on pump side. Thereafter I used studs to attach pump. To remove, undo nuts, screw out studs, pump falls off-
Keep spacer, use good gaskets, all screws on pump must be tight when reinstalled.
If you can get the T diaphram out and reinstall it, you may have a rebuildable late pump. Sometimes pushing the foot in while attempting install works. It is not easy. I like the late pumps better as the foot is smoother.
Linda
68 1600 Los Angeles, CA
New owners must read: the ultimate road trip, by Scott- roadsterroadtrip.com-http://www.roadsterroadtrip.com/index.php/readfromstart
v8_ranch
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Year: High Windshield-68-70

Re: Fuel Delivery Questions

Post by v8_ranch »

In what I have learned so far, I would assume when you guys in this community refer to something as EARLY or LATE, you are referring to pre 67.5(or 68) for early, and 68(69)-70 as late?
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redroadster
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Re: Fuel Delivery Questions

Post by redroadster »

Put a HF vacuum pump with catch bottle on the line from the tank
It should flow into the bottle and keep on with 2 pumps ...if not start there ( at the tank and lines )
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Mackn367
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Re: Fuel Delivery Questions

Post by Mackn367 »

v8_ranch wrote: Fri Oct 16, 2020 1:52 pm In what I have learned so far, I would assume when you guys in this community refer to something as EARLY or LATE, you are referring to pre 67.5(or 68) for early, and 68(69)-70 as late?
I'd say mostly yes but the 67.5 are tricky as they fall in both early and late - it's a lot of fun when ordering parts - even trying to figure out what is SAE and what is Metric haha.
Nick
1967.5 Roadster 1600
VIN: SPL311-13038
Orange County, CA