06302016, 11:02 PM  #11  
Board Member
Join Date: May 2008
Location: Rockland County, NY

Ref this thread for oil cooler t/stat housing oring PN  Mine needed 925093 square cut oring
Quote:
Using Steve C's (Xweb) Formula  bolded values are my revised numbers. Volume at BDC is (swept volume  pop up volume)+ flycut and ring land clearance volume + gasket volume + chamber volume. Volume at TDC is (volume in gasket  pop up volume) + flycut and ring land clearance volume + chamber volume. Volume of BDC over Volume at TDC is expressed as a ratio to one (xx:1) Your bore is 87.00 Your Pistons are 86.15 above the top ring land and the top ring groove is 8mm down from the crown. Your Valve Flycut measured volume is 2.1cc Your Piston sits at 0.65mm plus deck Your Combustion Chamber measured volume is 36cc Your head gasket is going to be 1.5mm compressed and has an inside fire ring diameter of 87.2mm (assuming a Felpro 21195PT2) So lets do some math... Swept Volume of the cylinder. Pi x R squared x Stroke 3.14285 x (43.5 x 43.5) x 67.4 3.14285 x 1892.25 x 67.4 400.831cc Volume of the piston 'pop up' 3.14285 x (43.075 x 43.075) x 0.65 3.14285 x 1855.4556 x 0.65 3.790cc Volume of the head gasket. 3.14285 x (43.6 x 43.6) x 1.50 3.14285 x 1900.96 x 1.50 8.961cc Volume of the ring land clearance. [3.14285 x (43.5 x 43.5) x 8]  [3.14285 x (43.075 x 43.075) x 8] [3.14285 x 1892.25 x 8]  [3.14285 x 1855.4556 x8] 47.576cc  46.651cc .925cc and then put these numbers into the equation, Volume at BDC = (400.831  3.790) + 2.1 + 0.925 + 8.961 + 36 = 445.027 Volume at TDC = (8.961  3.790) + 2.1 + 0.925 + 36 = 43.271 Static Compression: V at BDC / V at TDC (445.027 / 43.271) = 10.285:1 note: there is a chamfer at the top of the piston that is not accounted for  actual compression will actually be less. Not sure how much less. Need to see if I can get the specs on that from Wiseco, I never measured the depth of the chamfer and the diameter of the crown inside the chamfer... Last edited by lookforjoe; 07132016 at 10:29 PM.. 

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