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Thread: BB 454 Fuel Pump

  1. #1
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    BB 454 Fuel Pump

    The other day I was doing a 1/4 mile and at around 90mph it started loosing power. This was not at all like previous problems where when hot, it gets vapor in the system and it REALLY dies but responded to pumping the pedal, that came back again. This problem was more like it just stayed at 90 for a few seconds then picked up again. I don't know if I'm explaining that very well?

    Anyway, today I revved the engine a little and watched the fuel pressure and it dropped every time I revved it. Actually it pulsed from close to zero up to near 5 when revving it. At idle it pulsed from about 5 to 6psi. When I clamped the return line it did the same, and it held pressure after stopping the engine. I had another holley fuel pump (used) and went to install it but I over tightened the one fitting and cracked the pump. Both are Holley 12-454-11 pumps. Question is ... do I really need a Free Flow Rate of 110 gph?

    I did take them apart and try to make one good out of the two but the casting that cracked is the one with 3 check valves, and I'm not so sure of popping them out and swapping the casting, they are not made to be rebuilt.

    So do I really need a 110gph free flow pump? HP estimates were around 450.
    Tony

    1955 Bel Air Sport Coupe

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    I just read somewhere about an engine running out of fuel and a lightwhight push rod cured it. I'm shifting at 5500rpm, don't know if a hollow push rod is needed?
    Tony

    1955 Bel Air Sport Coupe

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    A friend has that pump on a 502 that made 525 hp at the rear wheels (with a bad tuneup). Should work fine for you if everything is working right. You should not need a lightweight push rod.

    FWIW he had some fuel pressure problems when he first put the 502 in it, replacing a 454. Turned out it was not the fuel pump. He had one of the "new" Holley carbs on it, piece of junk. Put his old 750 and old regulator back on, all was good.

  4. #4
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    Starting witht the inlet, and fuel line would be a good thing to verify first. Hard to suck fuel through a restriction. Fuel pump rod is not the issue. The 427 I once had 45 years ago could fly at 7000 rpm with OE stuff. I had 2 different 427's machined at Speed-O-Motive in West Covina, California, with cams custom ground at Sig Erson in Long Beach, when I was in the NAVY 72-76, and they performed perfect. I loved it back in the day out there when there was speed shops everywhere, blocks away! Now it has been replaced by amazon...
    Last edited by 55 Rescue Dog; 01-27-2018 at 05:10 PM.

  5. #5
    Registered Member chevynut's Avatar
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    110 GPH is way overkill for 450 HP. You only need around 38 GPH. Pull your tank pickup and make sure there's no junk on it or in your tank. If you only have a 5/16" pickup I'd recommend going to a 3/8" one and increasing your line size to 3/8" all the way to the pump.

    "There’s a simple formula to calculate GPH or LPH (liters per hour), but there are some variables to this formula, depending on your application. Norm Koval, a team leader in the Summit Racing technical department, typically follows this formula as laid out by the air/fuel experts at Holley:

    Optimal GPH = (Max. HP x BSFC) / 6
    Optimal LPH = (Max. HP x BSFC) / 1.585
    In order to make the proper calculation, you need to determine your variables for this equation, starting with your vehicle’s maximum horsepower (Max. HP).
    The second variable in the equation is BSFC, or brake-specific fuel consumption. BSFC is a measurement of the amount of fuel consumed per unit of power produced. According to Holley, an engine typically requires .5 pounds of fuel per horsepower every hour at wide open throttle. However, this number generally applies to naturally aspirated engines."
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


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    I was looking at lightweight push rods and then it hit me about the special rod for the roller cam and forgot what I used so I took it out and yes it is a lightweight with a bronze I believe tip for the cam, whew! I did put the pump back together and well it's the same as it was so I don't know what is going on with it yet. I have a quadrajet on it right now but also have an old Holley 800 spreadbore with mechanical secondaries. Only problem with that was the way the bowls hang out the fricken gas we have here boils on warm winter days and the summer gas boils on hot summer days. The Q-jet keeps the fuel cooler the way the bowl is in the middle. And yes I have a 1" spacer and both crossovers in the manifold blocked 100%. I wish they made an air gap spreadbore manifold for a BBC.
    Tony

    1955 Bel Air Sport Coupe

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    I have 3/8 line from the pickup to the carb. When I pulled the return line off it kept spewing fuel so I put the air hose to it lightly and while I heard the hissing of air from the fuel cap, it also suddenly shot gas out the pickup line so I think that is clear. The tank is only about 5 years old and has been drained a couple times so I don't worry too much about dirt in there.
    Tony

    1955 Bel Air Sport Coupe

  8. #8
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    If you have a "boiling" problem it is at rest, most critical when the engine is first shut off. If really bad, it might affect idle and cruise. But it won't affect WOT operation. Fuel doesn't have a chance to heat up at WOT. Not only that, with a carb there is self cooling at WOT.

    Are you monitoring fuel pressure real time? Or only at idle with a temporary gauge?

  9. #9
    Registered Member chevynut's Avatar
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    Is this a new problem, and did the car run fine at 90+ MPH before?

    What "return line" are you referring to? Are you running a regulator? Holley says you don't need a regulator with that pump. Also, you said you have a 3/8" line "from the pickup"....is the pickup itself a 3/8" one inside the tank?

    I had a 55 Chevy with a '67 Corvette 390 HP 427 in it and it would starve for fuel at high RPM....similar to what you're describing. I used the stock mechanical fuel pump with the stock 5/16" line and I'm pretty sure the line was the problem. It needs to be clear all the way to the pump with no restrictions. Make sure you don't have any restrictive fittings in the lines.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  10. #10
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    Quote Originally Posted by Rick_L View Post
    If you have a "boiling" problem it is at rest, most critical when the engine is first shut off. If really bad, it might affect idle and cruise. But it won't affect WOT operation. Fuel doesn't have a chance to heat up at WOT. Not only that, with a carb there is self cooling at WOT.

    Are you monitoring fuel pressure real time? Or only at idle with a temporary gauge?
    The old "running out of gas" problem has always, always, always happened when the temperature was high. It became *practically* non existent when I installed a filter with a bypass as close to the carb as possible.
    The boiling over at first happened while driving when the ambient temp was very high, then after adding the spacer and blocking the crossovers it stopped with the quadrajet but still did it at times with the holley after it was turned off, I believe only from the secondary bowl.

    There is a permanent gauge on the regulator, so no I can not monitor it while driving. Do people run them inside like a oil pressure gauge?
    Tony

    1955 Bel Air Sport Coupe

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