Big block chevy leakdown or fuel system info.

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Outlaw Funnycar, Sep 9, 2018.

  1. Outlaw Funnycar

    Outlaw Funnycar New Member

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    Have a 468 BBC with 6-71 with Teflon strips non helix. Has birdcatcher with 110 pump and 54 square nozzles in the hat only injection. I started out with 75% leak and 32° timing and it was so rich it was blowing 6 ft flames out of every pipe while idling. Shut it down re leaked it down to 55% and got lil bit better but still rich as hell. I'm stumped? This is in a 33 willys show car that will never be raced even though its certed to 7.50 but my question is what should I leak it to or what nozzles to install in the thing. Yeah those huge flames were cool but definitely couldnt run down the road that way lol. I do have an 80a pump if that would work. I'm used to blown hemi but this chevy has me stumped. It originally came out of a drag boat if that helps.
     
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  2. Outlaw Funnycar

    Outlaw Funnycar New Member

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    Roughly 11.25:1 compression with .725 solid roller cam
     
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  3. Dale H.

    Dale H. Member

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    Flames out the exhaust is too lean,not to rich
     
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  4. Mike Canter

    Mike Canter Top Dragster

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    Double check your timing and make sure you are not on the wrong side of TDC. Being way retarded will put nice flames out the exhaust
     
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  5. gordon tarbell

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    If this is straight methanol for fuel, just to get going set mag at 35* lock out no advance for conventional BBC openchamber heads. How much OD on blower?
     
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  6. Dave Koehler

    Dave Koehler Member

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    Not doing the math on your dual gauge leak down tester backwards are you?
     
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  7. Outlaw Funnycar

    Outlaw Funnycar New Member

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    Thankfully no my gauge on left is the high pressure and the one on right is low side. I think its too rich myself. With 10% overdrive that blower shouldn't make more than 15 lbs of boost and with 54 square nozzles in the hat and square b.v. and no port lines its rich as can be. Someone mentioned put 48s and go up to 52 max towards the rear of the hat. It has 110 pump on it now with a -8 feed but have a new from enderle 80a pump if that would work. A hemi is much easier to me.
     
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  8. Outlaw Funnycar

    Outlaw Funnycar New Member

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    And its iron head but will be getting a set of profiler aluminum heads before long due to its too hard to keep everything consistent being all iron I guess if that makes sense. My theory is with all iron it gets warm then I'm throwing cold methanol to it and it will more than likely make stuff move around a bit.
     
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  9. kosky racing

    kosky racing Comp Eliminator

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    I agree with Mike C on this it sounds like timing is off- somehow--Are you sure of tdc?-Going the right direction on degree hub?
     
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  10. SoDak

    SoDak Active Member

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    Here is another idea.
    Make sure the butterfly clearance is .006" and the idle check opens at about 3 psi.
    The higher the cracking psi of that idle check the richer it will be.

    Also, I've had it on a supermag where the condenser was bad and I had flames.

    For me its been too lean of an idle mixture or too retarded of ignition timing have been the main reasons for flames at idle.
     
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  11. nitrowannabe

    nitrowannabe Member

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    Are you checking TDC on the chevy at the first plug drivers side ? I think hemi has # 1 on passenger side. I see you said square bv.
     
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  12. Outlaw Funnycar

    Outlaw Funnycar New Member

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    Lol #1 is 1st cylinder on drivers side which is the same as a hemi. Firing order is the same also. Only engine where #1 is on passenger side is a ford.
     
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  13. Bjs344

    Bjs344 Member

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    I had a 110 pump on a stock iron headed BBC street motor with hillborn stacks. My first guess at a fuel system was so rich at WOT that it would die when you tried to put it up on the transbrake. Even then I had it idling perfect. You're missing something.
     
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  14. Dave Koehler

    Dave Koehler Member

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    Do not put the 80a on there or we will have a new thread.
    Iron has nothing to do with your issues.
    Staggered nozzles is a common thing to do but that's not your cure for this issue.

    Do the flames go out if you tickle the throttle or get more vicious?
     
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  15. bandit496

    bandit496 Member

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    I vote for timing--sounds like you are retarded. Rotor in front of #1 terminal CW. The rotation is different on a BBC than a hemi, so if you are used to timing a hemi, it would be different. JW
     
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  16. TAFC 5 81

    TAFC 5 81 Member

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    Sounds like timing (retarded) to me too. That combo should work fine with the 110 pump (as long as it is good). I would think you blower OD could go up to 30% or more (once you get the first problem figured out).
     
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  17. Eric David Bru

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    Are you running a crank trigger?

    If so, have you phased the rotor properly?
     
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  18. Dave Koehler

    Dave Koehler Member

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    Timing, low or no ignition power and low overdrive are all good possibilities. Maybe all 3 at once?

    With that low overdrive, small blower and assumed boost it should be going dead flood at the hit unless it has the largest main available.

    Here is a cure all question.
    What is different from when it ran, I assume successfully, in the boat?

    You aren't planning on driving this further than from the trailer to the show spot are you?
     
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