Irregular valve tip wear pattern

Discussion in 'Engine & Performance' started by SHOTROD81, Sep 11, 2017.

  1. gpmorgan

    gpmorgan Full Access Member

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    I had to do a lot of justifying to the old lady as to why I needed a 632 and come to think about it, I don't think I came up with enough. Lol
     
  2. Honky Kong jr

    Honky Kong jr Super Sarcastic Man

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    That's a good thing, the vacuum pump that is.
     
  3. gpmorgan

    gpmorgan Full Access Member

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    Is the vacuum pump very loud when running? I thought about using one.
     
  4. SHOTROD81

    SHOTROD81 Member

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    It's a little loud, but it's easily eclipsed by engine noise. This plant makes plenty of it.
     
  5. gpmorgan

    gpmorgan Full Access Member

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    Yeah the solid lift small block I had was loud also. The tall valve covers muffled it some and the 40 series mufflers dumped at the rear axle pretty much took care of the valve noise.
     
  6. MikeB

    MikeB Full Access Member

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    I suspect your pushrod guide plates do not center the rocker arms on the valve stem tips, but instead the rocker arms were leaning to one side. The fix for that on factory Vortec heads is using self-aligning rocker arms without guide plates.

    Wow, 628" lift?:eek: That means the retainers can't hit the seals, and springs can't coil bind until .678" valve travel. Which components did you use to get that much travel? Did you have the spring seats cut? Even a large-port Bowtie Vortec head is spec'd for .530" max lift out of the box.

    And FYI, even on re-worked Vortec heads, flow maxes out under .550" lift. They were designed to flow well at 400" lift and outflow all previous GM designs at that lift. And 20+ years later still outperform aftermarket heads at that lift.

    Simply put, your monster cam is not even close to being a good fit for these heads. In fact that would be true for just about any 23 degree small block head not designed for all-out racing.
     
    Last edited: Sep 13, 2017
  7. SHOTROD81

    SHOTROD81 Member

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    Other than a build sheet for the engine, which only said "customer supplied iron vortec" on the line for cylinder heads, I don't know what all was done to it before I bought it. I wish I had more details.

    In your opinion, what would be the better (and honestly, less expensive) investment: replacing the cam with one that better suits the current heads, etc...., or replacing the heads to some better suited to this cam? It currently has a 750 Mighty Demon with a Super Victor intake, if that steers it in one direction or another. No matter what I do, it will have plenty of power for my tastes. I just want to get to a point where I can have some fun without feeling like I'm on the edge of another breakdown.
     
    Last edited: Sep 16, 2017
  8. Guardian

    Guardian Full Access Member

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    What type of rockers did you have on these?
     
  9. SHOTROD81

    SHOTROD81 Member

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    Harland Sharp
     
  10. Guardian

    Guardian Full Access Member

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    I agree with MikeB. The guide plates are not aligned and causing the rockers to not contact the stems properly. The solution is either correct the geometry with these heads or replace them. You might be able to utilize offset rockers but that isn't common.
     

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