DragBikeMike
Serious Thumper
Offline
SuzukiSavage.com Rocks!
Posts: 4194
Honolulu
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So, the negative deck height of .162” combined with the head gasket thickness of .028” results in the piston being situated exactly .190” from the head at TDC. Since my favorite quench clearance is .040”, I would need to reduce the cylinder height by .150” to achieve my desired quench clearance. Another option would be to increase the piston compression height (distance from the centerline of the wrist pin to the flat top of the piston) by .150”.
Both options have tall hurdles to clear.
Lobbing .150” off the top of the cylinder requires machine tools and will result in the cam chain going loose as a goose. Also, it will retard cam timing, possibly cause interference problems between valves & piston, and create fit-up issues with the forward chain guide, dowels, etc. I have the machinery, correcting the cam timing is easy, resolving the fit-up issues is straight forward, but that loose cam chain might be a hard problem to solve.
Installing a piston with an additional .150” compression height will require a special order (minimum purchase, ten pistons). Also, increasing the compression height affects the thrust action of the piston skirt which, IMO, would require engineering analysis (i.e. Wiseco engineering staff should be giving this modification a good look.) Piston thrust is affected by placement of the wrist pin, the length of the connecting rod, the stroke, angular velocity, etc. Way above my pay grade.
I’m not willing to throw down a big wad of cash on ten special pistons (nine of which I don’t need), but I really want to see how this engine will perform with proper quench. I decided to satisfy my thirst for quench by lobbing off the top of the cylinder. If I can figure out a way to deal with the loose cam chain, maybe I can prove that the engine runs great with tight quench, and in the process conjure up some additional forum members who might be interested in the special piston.
No guts no glory.
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