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Thread: Bypass Spacer for Mallory 140 Pump

  1. #1

    Default Bypass Spacer for Mallory 140 Pump

    Forgive me, I don't know the part numbers that succeed from change of company/ownership, but I have a Mallory 140 pump and a Mallory 4307M regulator.

    When using the pump with a return style regulator there's a spacer (supplied in a bag with the regulator) that's supposed to replace the spring in the 110/140 series pump, to shut off the pump's built-in regulator. Apparently, because there was no "Marine" pump, my marine regulator didn't have this part in the parts bag.

    Well, my regulator and pump keep arguing when I'm deep into the throttle, so the fuel bowl suffers from the disagreement. I posted two years ago after contacting Mallory, MSD, Century Performance, Jegs, and even Amazon, asking at Summit forums, if they knew where to find the phantom, illusive spacer and a tech from MSD replied, instructing me to email them with my shipping info. I did. No reply, no spacer a month later, so I did it again. Got fed up so tried this and that, eventually dsmaging the Plunger Pad, resulting in fabricating some from neoprene.

    Two months ago, I emailed again saying my truck was nearing completion and I'm approaching winter months, need this spacer please. Truck is done.

    I emailed again last week. No reply, no spacer. I said "fugghedaboudit", cut a near 3/8" O.D. piece of brass tubing, 3/8" long, pulled the spring, assembled and installed the pump. Off to work I go. On the way home, I nearly stalled and reluctantly limped home at 35 in a 50 at 3am, in temps of 12°F. Not cool! Dry cylinders result in cylinder/ring/piston damage.

    Can someone here from accessories reply to me and maybe even sell* me a parts bag that has the Bypass Spacer (and plunger pad) so I can enjoy the approximately $1,000 custom cardiovascular system I installed in my vehicle? Preemptive Thank You for your reply(s)/help.

  2. Default

    Could you please tell me if you heard back from technical support? I hope you got an answer before you damaged the rings, cylinders & pistons.

  3. #3


    No, they haven't replied. The truck has been down cause I missed all events for spring & summer,(07/04/2021), and I'm just fed up with the BS. I'm not about to spend another $300-$800+ on a pump when this one is pretty much new. I had someone with a lathe wanting to fabricate a brass spacer for me, but we decided to go with one piece of aluminum, a Bypass Plug combined with a Plunger, w/recess for the Bypass Plunger Pad. I'm considering making the Pad out of 3/32" GFLT-600S (just buy a 12" x 12" sheet and stamp Pads for eternity), for it's resistance to ethanol. FWIW, others have made a Bypass Spacer out of brass round stock, 0.309" in diameter x 0.320" long. To minimize parts, one could just take a set screw about 3/8" longer than that which comes with the pump and grind/file/machine the threads off 3/8" of the end, trimming it down to 0.309" in diameter. Thank you very much for the concerns.

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