Noob BBC questions

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Ruff Time, Jun 7, 2017.

  1. Ruff Time

    Ruff Time New Member

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    Hi i hope you can help a noob like me, i'm going to order pistons now and have some questions and you seem to know very much. It's the first engine I'm building from scratch.

    What static compression ratio,
    and what rollercam,
    and what ignition system do you recommend?
    And what nossels will it run on.

    Merlin lll 85110 pro block The block has 10.160"deck height with a o-ring groove and the bore is now 4.634" The crank i's a 4.500" Lunati and Eagle 6,700" steel rods and Brodix BB 2X alu heads, they have 118cc chambers and 2300"-1880" valves max lift .820". My blower i's a Mooneyham 10/71 with striped lobes a 50 and a 60 tooth sprocket. And a Enderle fuel injection hat and a Enderle 110 fuel pump. I'm looking for 1500hp on methanol.

    Re Johan W Sweden sorry about my English


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  2. Critical Mass

    Critical Mass Member

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    You are asking a lot!

    First of all what are you planning to do with the 607 in3 motor? The ideal size for a blown motor is around 500 in3. Your size is more like a nitrous motor.

    I'm assuming it is a water block; therefore, the cylinder walls are going to be pretty thin with a 4.634" bore. Also, it is way too early to decide on pulley sizes now, you don't know what kind of boost your blower will produce with your cam. For the hp you have selected you have the right fuel pump. With blown alky motors I like to shoot for around a 11.5 CR. With your 6.7 rod and 118 cc head volume you will need a ~1.22 compression height pistons with 30 cc dome volume. This will give you around 11.6 CR with .027" in the hole.

    Aluminum rods are a lot more forgiving then steel rods when it comes to detonation. What would you rather do, hit your crank bearings with steel hammer or a aluminum one. Good experienced tuners can get away with it for a while, but most of us can't.

    If you only want 1500 hp I don't see a problem. But most of us are never satisfied.

    I have only listed a few things that you need to consider. I hope this helps. Joe
     
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  3. Ruff Time

    Ruff Time New Member

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    Well i don't know so i have to ask a lot :)

    Thanks for your answers, well i'ts for a monster truck and the block is the same as 100+ monster jam trucks are running up to 572ci, but i'am on a budget so everything so far are used parts and the pulleys where included and the belt is too long anyway.

    Wall thickness is .440 at 4.490 bore so yes i'ts thin at 4.634" bore.

    11.6 CR sounds good I've heard everything between 10,5-13 CR, 13 was for not killing the spark plugs.

    Aluminum rods it will be then.

    To a monster truck 1500hp is plenty and I want a durable motor.

    What about the cam and ignition, any thoughts :)

    http://.www.rufftime.net
     
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  4. Critical Mass

    Critical Mass Member

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    I'm no expert on cams. I can only tell you what was recommended to me and what I use: Bullet CHB 319/336-14R Part #502000.

    Ignition: MSD 44 mag with a 8147 box. Controlled with a MSD 7730 Grid. I been told that this set up is over kill.

    People on this site will tell you to have your fuel system flowed. Once you have that done they are more open to answer your particular questions. The reason is they can't give you a correct answer if they don't know what your set up is. You need to know your boost, pump fuel flow rate, nozzle area, and barrel valve type just to mention a few.

    Here are some basic formulas you might want to play with:

    Required fuel (alky), gpm = ~0.36 x Boost, psi
    HP = fuel flow, gpm / .0053
    Therefore, for 1500 hp your engine will need to burn ~8 gpm.

    Good luck with your monster truck, Joe
     
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  5. Ruff Time

    Ruff Time New Member

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    Thank you for your input, when the motor is running everybody are telling you what you did wrong but they didn't warn you before you paid for the parts:p:D

    Thanks:)
     
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