Contents Section: Crankcase, Suspension All sections

Engine design Porsche Boxster S 987

Engine design

Designation987987 SCayman S
Type6-cylinder aluminum opposed-cylinder engine, water-cooled
CrankcaseVertically split light alloy cylinder housing with separate aluminum crankshaft bearing housing with GGG inserts
CrankshaftForged, supported by 7 bearings
Crankshaft bearingsThree-component plain bearingsØ 63, sub-groove, three-component plain bearings
Connecting rodsForged Crack connecting rod
Con-rod bearingsThree-component plain bearings
PistonsLight alloy castPressed light alloy
CylindersLokasil oil running surface
Cylinder headThree-part light alloy head
Valve guideBearing material pressed in
Valve arrangementTwo input and output valves per cylinder suspended in parallel v-format
Diameter of inlet valve33.3 mm37.1 mm40.2 mm
Diameter of exhaust valve28.1 mm32.5 mm34.5 mm
Valve lift of inlet9.85 mm10.5 mmLarge 11 mm Small 3.6 mm
Valve lift of outlet9.85 mm10 mm11 mm
Valve gearVia flat-base tappetsSwitchable flat-base tappets
CamshaftChilled cast iron, hollow-cast
Camshaft adjustmentPorsche VarioCam with axial camshaft adjustmentPorsche VarioCam Plus with axial camshaft adjustment and valve lift control
Camshaft driveFrom the crankshaft via a 3/8" tooth-type chain to the intermediate shaft, and from there to the inlet and exhaust camshafts via one 3/8" duplex roller-type chain each.
Valve clearanceHydraulic valve clearance compensation
Timing: intake opens, early/late21° before TDC/19° after TDC26° before TDC/14° after TDCLarge lift 29° before TDC/11° after TDC
Timing: intake closes, early/late9° after BDC/49° after BDC20° after BDC/60° after BDCLarge lift 20° after BDC/60° after BDC
Timing: intake opens, small lift, early/late1° before TDC/39° after TDC
Timing: intake closes, small lift, early/late59° before BDC/ 19° before BDC
Timing: Outlet opens39° before BDC39° before BDC50° before BDC
Timing: Outlet closes8° before TDC6° before TDC4.5° after top dead center