looking for a little more HP: Big Cam 400 NTC BC3

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by sodbuster59, Mar 24, 2022.

  1. sodbuster59

    sodbuster59 Bobtail Member

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    recently bought a 98 FLD120 with 300K miles, that has a BC3 Big Cam 400 in it and would like to tweek it up to 470 (ish) and am looking for advice on this.

    98 FLD120.jpg
     
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  3. spsauerland

    spsauerland Road Train Member

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    Dino soar Thanks this.
  4. SmokinCAT

    SmokinCAT Road Train Member

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    Safest way to do it is with a higher flowing set of injectors.

    This keeps the fuel pressure down and stress off of the cam.

    If it is a true 400 then the stock turbo will be okay to that power.
     
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  5. Dino soar

    Dino soar Road Train Member

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    Hubba hubba! I think I'm jealous!

    You have two choices. The safest choice is to turn it up 10% and forget it. The other choice is to call premco and tell him what you want and he'll set you up with injectors and pump work and turbo and timing whatever.

    One word of warning is that people will tell you that they turn these engines up and they have no problems. I think the jury is out on that. The most reasonable answer that I can give you is the closer to stock that you keep your engine the safer it is. And the farther you stray the more dangerous the waters become.

    You would have to put a gauge on your engine and see where you are at and what your CPL calls for as far as fuel pressure but I myself would not go beyond 200 lb or so. I might be conservative on that some guys run 210 or 215 maybe but I don't want any camshaft problems. High fuel pressure eats camshafts. It's better to put an oversize injector in and run a lower fuel pressure

    Some guys will tell you you can turn it up to whatever you feel like and it's just depends on how you drive etcetera but they're not the ones that have to get back into it and put their time and money into it especially if you're planning on making a living with this truck.

    The other issue is that if you don't have any history on that engine if it never has been cut for the lower press-fit liners don't put any more fuel to it. Those liners actually move around and putting more fuel to them especially if they're not lower press-fit liners can cause you quite a bit of problems.

    I also have the big cam 3. To me that was the best of the bunch. Mine does have lower press-fit liners.

    But wow I really like that truck. That's 100% awesome!
     
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  6. W923

    W923 Medium Load Member

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    Wouldn’t a 98 be a n14 mechanical?
    Probably with stc if it’s a 400
    Not that the above recommendations aren’t good but different injectors are probably going to be big money
     
  7. W923

    W923 Medium Load Member

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    Another thought, if that’s a bc3 it’s probably running a water aftercooler.
    Going to air to air will make a significant improvement and won’t burn any more fuel
    Basically free power
    N14 parts will work for a conversion
     
  8. sodbuster59

    sodbuster59 Bobtail Member

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    BigCam400BC3label.jpg BigCam400BC3pic.JPG Thanks for the replies. my first truck was an 87 flc with a big cam 400 and I loved that girl. I looked EVERYWHERE for this one, and am pleased to say the least. Started as a glider project when new. Present owner built it with the present engine and a 9sp, recently upgraded it with a 13, and yesterday let me buy it! Is it a BC3? here you go.... and oh, I would love to get 50-100hp more out of it safely but I'll even be happy with her just the way she is before I do something 1/2 way and do damage.
     
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  9. SmokinCAT

    SmokinCAT Road Train Member

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    No, 98 would not be mechanical at all for cummins, this truck would have been put together.
     
  10. SmokinCAT

    SmokinCAT Road Train Member

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    Just adding air to air doesn't add power on a big cam, and it actually makes idle combustion worse by not warming the intake air. Ideal intake temp on a big cam for optimal performance is 160*
     
  11. SmokinCAT

    SmokinCAT Road Train Member

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    Looks like a recon crate engine to me, gonna guess that the truck was a glider and engine was installed when built. It most likely has all the updates to the block, it could even have the updated BC4 block as some recons were produced like that.
     
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