RPMs not increasing as I approach finishline

Discussion in 'Race 400/430/455' started by BQUICK, Jun 3, 2013.

  1. BQUICK

    BQUICK Gold Level Contributor

    I think I found the problem.. Both my feed and return aluminum fuel lines were badly crushed. Must have happened when stuffing the motor in on the Jag. Explains why it would go 134 whether it went 9.80 or 10.10 (on throttle stop) and why it was burning the ground electrodes off the plugs. Sure made it consistent though. Like having a governor on it.
    With new lines I can adjust fuel pressure up or down. Return being crushed wouldn't let pressure go below 7. Now I can turn it to 4 if I want.
    Can't wait to run it....it's likely that it was running with the crushed lines for the last 400 passes or more!
     
  2. Clanceman427

    Clanceman427 Hardtops need not apply

    Yep, it's not about fuel pressure but fuel volume. If you have an electric fuel pump you can run a test by disconnecting the lines at the carb and running them into a bucket. See how long it takes to move one gallon. There is correlation for how many seconds and et range. BG had a great write up about it but the company is gone.
     
  3. BQUICK

    BQUICK Gold Level Contributor

    Yeah I had pressure but no volume. Basically on the verge of running out of fuel every pass. Valve springs were fine.
     
  4. blown455

    blown455 Pit crew

    check oil filter for metal running out of fuel in high gear hard on main bearings.
     
  5. BQUICK

    BQUICK Gold Level Contributor

    Just replaced block. Was cracked in 2 cylinders. Bearings looks great (coated). I don't think it was detonating just real lean. If I lifted a little on top end it would pick up.

    Fresh and ready for Norwalk!
     
  6. blown455

    blown455 Pit crew

    If it cracked the block it was detonating, to many buick guys underestimate how bad detonating is. thats why I run very low timing and dont hurt stuff.. to many guys think power is cracking the block, it is not. lean will burn something not crack it, do yourself a favor and put the timing @ 32 and leave It . just trying to help... Rod
     
  7. BQUICK

    BQUICK Gold Level Contributor

    The most I ever ran was 34 retarding back to 30 after 5000 rpm. A few passes were run a Maryland Intl Raceway in 105 deg heat with the Meziere pump not working along with the squashed fuel lines! I'm thinking that's when the cracks in the cylinder walls occurred. I'm sure it was detonating with no water pump action!
     

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