Cleaning up my fuel system. Questions.

Discussion in 'Street/strip 400/430/455' started by rkammer, Jun 15, 2020.

  1. rkammer

    rkammer Gold Level Contributor

    I've found by running with a fuel pressure gauge that my fuel system needs attention (fuel pressure drops to zero at full throttle) so, I'm dropping the tank, replacing all the rubber lines and checking for kinks in the 3/8 steel lines. I plan to either replace the in-tank fuel sock or remove it altogether and add a RobbMC billet pre-filter before the fuel pump.

    http://www.robbmcperformance.com/products/filters.html

    So, is one method better than the other? And, should I also consider installing one of the RobbMC sending units and just pitch the factory sending unit? (my factory fuel gauge is still very good and accurate)

    http://www.robbmcperformance.com/products/1069_gmsend.html

    Once I get the fuel system operating right, I'll then see if I need to take the next step and add a pusher pump or the RobbMC high performance mechanical. My horsepower is on the border of maybe needing it. (468 HP)
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I did both. I run one of the CV products mechanical pumps that I got from JW. More expensive than Robb MC.
     
  3. rkammer

    rkammer Gold Level Contributor

    Thanks, Larry. Did the RobbMC sending unit allow your fuel gauge to remain accurate? And, where did you install the billet filter?

    And, why is the RobbMC sending unit any better than the stock unit with the sock removed?
     
  4. Bens99gtp

    Bens99gtp Well-Known Member

    Larger line size means less restriction
     
  5. rkammer

    rkammer Gold Level Contributor

    Makes sense but, is it still a benefit with my stock 3/8" fuel lines from tank to pump?
     
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Yes, same accuracy, works great. My billet filter is right under my driver door, inside the frame with the fuel line. It is this one,

    https://www.summitracing.com/parts/sum-230116

    The pick up inside the tank is also 1/2" with no sock. It's bigger than the stock unit.

    Yes, think of it this way. When and if you do upgrade to 1/2" line, you'll be ready to go, especially if you select the option to add AN fittings to the pick up lines as I did.
     
    Last edited: Jun 15, 2020
  7. rkammer

    rkammer Gold Level Contributor

    Can the fuel line be cut and the AN fittings installed with the chassis and frame un-separated?

    And, why did you decide on a $60 filter instead of the $30 RobbMC unit?
     
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I'm talking about the sending unit ends. Robb has an option for AN fittings. -6AN or -8AN fittings (20.00 option). I would do this contemplating going to bigger push lok or teflon lined hose in the future.

    https://www.robbmcperformance.com/products/1069_gmsend.html

    You don't have metal line back at the fuel tank, it is rubber. There might be adapters to go from Male AN to a nipple you can attach rubber hose. I'm not sure.

    Jim Weise recommended the filter, and it had AN ends on it. I just bought 2 fittings and spliced it into my fuel line. The Robb Mc filters need NPT fittings. I paid more because I wanted that type of installation. All AN fittings are way easier and reliably leak free. You get what you pay for.
     
  9. rkammer

    rkammer Gold Level Contributor

    I understand how the lines from the tank interface with the steel lines back at the tank. I was referring to how you were able to splice the fuel filter into the steel line under the driver's door? Can the line be cut and AN fittings installed without removing the fuel line?
     
  10. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    My fuel line is Aeroquip FC 598, it is very tough stuff, but you can easily cut it with a sharp razor.

    https://hosewarehouse.com/products/...-textile-braid-fc598-8?variant=11773020340260

    All I did was cut a section out of the hose, and install 2 of these,

    https://www.summitracing.com/parts/...MIu9Lf5oOF6gIVPOaGCh0jrADdEAQYAiABEgLnCvD_BwE

    Then screwed the filter in.
     
  11. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Ray, send me an e mail at Larrymta@verizon.net. I'll send you a word document from Jim Weise on how to run the fuel line.
     
  12. rkammer

    rkammer Gold Level Contributor

    Thanks for the document on running new fuel lines. Perhaps I didn't explain right. To start with I'm leaving the current 3/8 fuel line inside the frame from pump back to tank. But, I still want to replace the rubber line under the driver's door with a billet filter with hose barbs on both ends to insert back into the factory 3/8 line. So, is there enough room to do that? (The billet filter, including the hose barbs is about 5 inches long). I have no way of raising the car up at my house to see how much room there is and want to be able to tell my mechanic, Kevin King of KDK, what I want done.
     
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    No, I understand what you want to do. I can tell you that no, there isn't enough room to do that. The rubber section is nowhere near that long from what I remember. You'll need to cut out some of the steel line. Are you installing the Rob Mc pick up and the pump, or just the pick up?
     
  14. rkammer

    rkammer Gold Level Contributor

    To start with just the pickup and his 100 micron 3/8 billet filter. I don't mind cutting out a section of the steel line under the driver's door but, when I do, will there be at least enough open space in the frame to flair the cut line and work the filter into it? Or maybe once the steel line is cut we'll be able to pull enough out from the frame next to the fuel pump to add the filter?
     
  15. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    If the filter has hose barbs, you don't need to flare anything. I'm not sure how much you can pull the line out of the frame. It depends on where and if it is clamped. My original fuel lines were re done by the PO when he did a frame off on the car in 1997, and I don't remember exactly what they were like. It's been awhile.
     
  16. rkammer

    rkammer Gold Level Contributor

    I understand I don't need to flair the hose barbs but what about the steel line that has been cut and the bead removed? I guess we're just gonna have to let Kevin put it up on the rack and do the filter the best way possible.
     
  17. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I would just clamp the line. It isn't going anywhere and it won't leak at 7 psi.
     

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