Sighn groves ???

[stroker800]

  Is it possible for the grooves to work in a shovel combustion chamber due the the lack of a squish area such as an evo...
Also with the polysphere design in the shovel,,,,how was "Hemi Design" guy in IL making the evos work any better?,,,A hemi will only perform in the plug is between the valves.
Dave

[Hybredhog]

    As you mention, It alll comes down to squash, as in about .030 around the out 1/2" ring of the cobustion chamber & piston can be done with careful measuring & machineing, Not to mention manifold pipe fitment if you drop the head to much. Sqash is how the Hemi head guy is doing it, but groves really wouldn't have an aplication on a shovel

[Pzokes]

Grooves might have an application in a Shovel with one spark plug per head.  In the 70's, on high compression Sportster drag bikes, it was found that the side of the piston away from the spark plug was not getting good burn.  Some of the racers came up with what they called "fire trenching".  It involved cutting a wide groove across the top of the piston.  It worked opposite of a groove.  It caused the flame front to pass through this wide groove (almost as wide as your small finger) to burn the gases on the other side of the piston.

What would you think of cutting 1/2" wide 30 degree squish bands on the edge of the piston and head, with almost zero deck height, to get some movement in the combustion chamber and then using a Crane or Power-Arc multi-spark ignition to assist in the burn?  A directional vane (like S&S heads) or directional port work (like some head porters do) could be done on the intake port to also get some spin on the gases too.  Of course it would require someone with much more than my limited knowledge to come up with a design that would work in the real world.

[Hybredhog]

    Years ago, I helped a friend build a shovel drag bike useing the S&S 98" kit as a stating point. As you said, Money, time, machining, welding, and more money went into the heads to do just that, make a viable squash band, like a 2 stroke chamber. Fins/ ribs in the intake don't really do much other than take up space & do increase volocity in the port because it is smaller, one of a shovels ports biggest faults. We welded up the floor & the bowl area of the intakes, making them approx. the same as an evo, to increase volocity. Long story short, The thing ran like a MF'er. Theres no money in racing in rural areas, and it needed a lock up clutch bad...Jeff