Recommended Design Clearances
Valve to piston .100” minimum
valve to piston lateral clearance (lateral clearance between valve and valve recess in piston) .025" minimum
Squish (piston to head) .040”. minimum
Valve Spring Coil Bind Clearance: .050”-.060” minimum
Engine Clearances (derived from SP1000/G5 manual):
Crankshaft to big end bearing diameter clearance: .0012-.0021”
Front main bearing diameter clearance: .0009-.0022”
Rear main bearing diameter clearance: .0012-.0027”
Wrist pin to bushing diameter clearance: .0008-.0018”
Connecting rods to crank side clearance: .012-.020”
Piston ring gap .012-.024"
Connecting Rod Weights
Stock 850 Lemans: 615 grams
Stock Lemans IV: 607 grams
Carillo for Lemans IV: 502 grams (.25 lb lighter than stock EACH!!!)
Valve Spring Data
123 lbf @ 0lift; 188 lbf @ full (.368” valve) lift (B-10 Cam) –stock, from Lemans IV manual
114 lbf @ 0lift; 184 lbf @ full (.368” valve) lift; coil bind at .466” valve lift (B-10 Cam) –stock (measured by me)
90 lbf @ 0lift; 190 lbf @ full (.368” valve) lift (B-10 Cam) –recommendation From Amadeo Castellani/Raceco UK
