Fuel lines in my ka24de swapped 510 wagon?

[Joshua Jones]

So I am doing the swap on my 71 510 wagon. Everything I have read says i need to replace the fuel lines and install an inline fuel pump. So here is the question, why can you not use the stock fuel lines with a new inline fuel pump. Is it a sheer volume of gas issue or can I mod the tank and just use my stock lines? Along with that who is using stock lines on this setup if any?

 

 

Thanks Joshua

[Just Joel]

From what I have read, the diameter of the line is the issue... Need to bump it up a size for flow.

 

Later

Joel

[jesusno2]

From what I have read, the diameter of the line is the issue... Need to bump it up a size for flow.

 

Later

Joel

 

The stock fuel lines are fine I'm using them on my ka goon just remember the return is the pressure side so use the bigger 5/16 for that and the 1/4 for the feed. Only reason to go up in size would be for a turbo application. Otherwise its just added costs for no reason

[thisismatt]

The stock fuel lines are fine I'm using them on my ka goon just remember the return is the pressure side so use the bigger 5/16 for that and the 1/4 for the feed. Only reason to go up in size would be for a turbo application. Otherwise its just added costs for no reason

Unless your regulator is at the tank on the return line, then the return is not the pressurized side...or am I misconstruing what you're saying? You can't restrict the flow after the regulator, or the regulator won't be able to do its job; so what you're saying about line size may be true in that regard...just depends if the line is big enough to allow the necessary flow at or below the necessary injector pressure.

[Joshua Jones]

After some playing around I decide to run a new metal line for the feed and use the stock feed as the return. I am going to have to have a local shop change out the nipples on my tank but it should be solid other than that I hope...... I figure the old feed line should be ample as a return line.....

[Datsfrodo]

I would and did Replace, the lines. Stock carb lines are good for about 7psi. Since you will be running a Ka with a Pressurized pump you need to upgrade the lines. I paid 1.49 a foot at Auto zone just last week. Its not that much of a deal breaker, It took one week for my line to go out.

[datzenmike]

Have to agree. The stock size should be fine but it's 40+ years old and in some cases rusty. You are going to run at about 40PSI from the tank area vs. the stock suction from the mechanical pump at the front. If replacing, it won't hurt to go slightly bigger but why? the stock can pass tons of volume. Ever had a gas line siphon when changing a filter? That's way more than a motor could use and that's without a pump pushing it.

[mhinkens]

Resurrecting this post just to confirm all of the research I have been doing....
 

I am putting a 92 KA24de into a 72' 510. I do NOT think I have an evap system in the trunk and actually think my tank may be venting to atmosphere or into the fuel fill area via hose (car is in storage for winter so I cannot go open the trunk to check but I am almost 100% that I do not have the EVAP system back there).
 

1. Can you just vent from the tank to atmosphere? (My car constantly smells like gas when I get in after a day.)
 

2. Does the Fuel System Diagram sound like this for the KA in the 510? 
 

Tank (bottom bung) to engine --> 5/16 Rubber EFI Hose --> 5/16 metal hardline --> 5/16 Rubber EFI Hose --> In-Line Filter --> Hose --> Fuel Pump (see specs below) --> Rubber line to back of OEM 240sx Fuel Rail --> OEM 240sx Fuel Regulator --> 5/16 Rubber EFI Hose as return (BYPASS 510 Flow Guide Valve) --> 5/16 metal hardline --> 5/16 Rubber EFI Hose --> Tank (top bung)
 

3. I am thinking of upgrading all lines to 5/16 but that leaves one bung coming out of the tank for the fuel feed that is too small for the upgraded lines (its 1/4?). Can that just be stepped up with a hose adapter or do I need to replace the bung on the tank?
 

4. (Last one I hope) Running EFI rubber hose to the hardline in the system is okay? NO AN fittings are needed for the 240SX system? [I am doing an inline WALBRO (debating the GSL 392 at 255LPH/43.5psi versus the GL394 at 190LPH/43.5psi since the OEM pump is 100LPH/43psi).]
 

Thanks to anyone who can help. This is my first swap and I am reading a ton all over the forums and in the manuals but its still a bit confusing so I wanted to confirm with others who have done it!