Pistons. Where can they be cut?

Discussion in 'Rotating Assemblies' started by NitroInjected, Aug 4, 2018.

  1. NitroInjected

    NitroInjected Well-Known Member

    I have a set of stock forged pistons from MAHLE The skirts are HUGE. They look more like diesel pistons Cant I mill most of this skirt off flat with the bores? Also that cubic point above the pin bore? Then some crown work? I am looking to get 100 more grams off of the up and down moving parts in total. This paired with the work I have mentioned on other threads about removing a rib on the conrods should get me there. The goal as mentioned in other threads is to reduce stress on the rod big ends.... The pulling forces during open valve. For anyone who is reading my stuff for the first time This engine suffers from mass and oil issues that I am working to correct. The smart choice here would be to run better pistons but money..
    [​IMG]
     
  2. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    So risky without knowing where the exact thermal expansion rates are on each area.
    Stress riser points.

    I have only seen blueprints of old TRW Powerforged pistons.
     
  3. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    Autotech makes the lowest cost custom pistons.
    Need the right forging blank.
     
  4. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    It was done empiracal testing by TRW.
    Ran them in past.
    Super strong.
    A little heavy.
     
  5. NitroInjected

    NitroInjected Well-Known Member

    I need an opinion on this: [​IMG]
     
  6. NitroInjected

    NitroInjected Well-Known Member

    Goodish news is pins are in. Photos later as I have work.
     
  7. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    You can cut away al the skirts with a Hacksaw.
    Run it and Blow it up.

    Custom Racing Aries Or Diamonds Pistons are the Only Way to Go.
    Need the $1000 + Cash.
    Most Important Thing building Race Engines Is $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$.
     
  8. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

  9. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    http://garage.grumpysperformance.co...train-clearances-and-problems.528/#post-57678

    http://garage.grumpysperformance.com/index.php?threads/checking-piston-to-valve-clearances.399/

    http://iskycams.com/shop/index.php?main_page=product_info&products_id=2243
    https://www.summitracing.com/parts/isk-pnt-134

    https://www.lindytools.com/ihpc
    Turns with an electric drill!

    be aware you may find that the machine shop cost of custom machining pistons
    for increased valve clearance may cost a significant percentage of the cost of buying new (IDEALLY FORGED PISTONS),
    and keep in mind that pistons with domes that build increased compression are generally designed for the required valve clearance of high lift cams,
    while standard cast or hyper eutectic pistons may not have the required thickness in the required areas that allow deep valve relief cuts.
    and Ive seen machine shops cut 2.2" diameter valve notches to clear 2.3" diameter intake valves and even worse, the valve notch was not centered on the valve centerline of the cylinder heads
    this is where a use of some clay and a dial caliper,
    during the assembly process is critical

    [​IMG]
    don,t forget you check BOTH the depth the valve extends down into the valve notch on the piston and how close the radial outside edge of the valve extends out towards the edge of the valve clearance notch

    [​IMG]
    [​IMG]
    [​IMG]

    [​IMG]
    inspect carefully and use modeling clay over the whole piston dome to verify potential piston to valve contact areas

    In Head Piston Cutters for valve clearances that have changeable rods for different guide sizes. They are high speed steel cutters made in sizes ranging from 1” to 2-1/2” diameters. They are spun in the head by an electric 3/8” drill for fast, clean and easy use.



    M-2 Heat Treated Steel Cutters, to last for long life and they thread on guide rods for rigid solid cutting.



    In-head piston cutters: $88.50, any size available from 1” to 2.5” – give us a call.



    Guide Rods: $34.50

    Guide Rod sizes: 5.5 mm, 6 mm, 7mm, 8 mm, 5/16”, 11/32”, 3/8”

     
    Last edited: Mar 17, 2020
  10. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

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