6.2L LS3 V8 · Clearances

LS3 Clearances & Tolerances

The running clearances, end play, ring gaps, and journal tolerances that decide whether a rebuild is in spec. Production figures are the as-assembled targets; service limits are the wear thresholds for used parts. Both are shown in metric and imperial.

38 entries

Clearance Production (mm) Production (in) Service limit Detail
Main bearing oil clearance Main Bearings 0.02 – 0.052 mm 0.0008 – 0.0021 in 0.02 – 0.065 mm
Main bearing journal diameter Crankshaft 64.992 – 65.008 mm 2.558 – 2.559 in 64.992 mm
Main bearing journal out-of-round limit Crankshaft 0.003 mm 0.000118 in 0.008 mm
Main bearing journal taper limit Crankshaft 0.01 mm 0.0004 in 0.02 mm
Main bearing journal runout limit Crankshaft Not separately spec'd
Crankshaft endplay Crankshaft 0.04 – 0.2 mm 0.0015 – 0.0078 in
Connecting rod bearing oil clearance Connecting Rod Bearings 0.023 – 0.065 mm 0.0009 – 0.0025 in 0.023 – 0.076 mm
Connecting rod journal diameter Crankshaft 53.318 – 53.338 mm 2.0991 – 2.0999 in 53.308 mm
Connecting rod side clearance Connecting Rod 0.11 – 0.51 mm 0.00433 – 0.02 in
Camshaft journal diameter Camshaft 54.99 – 55.04 mm 2.164 – 2.166 in
Camshaft bearing oil clearance Cam Bearings 0.023 – 0.098 mm 0.0009 – 0.0038 in
Camshaft endplay Camshaft 0.025 – 0.305 mm 0.001 – 0.012 in
Camshaft lobe lift (intake) Camshaft 8.24 mm 0.324 in
Camshaft lobe lift (exhaust) Camshaft 7.77 mm 0.306 in
Camshaft runout limit Camshaft 0.05 mm 0.002 in
Cylinder bore diameter Engine Block 103.241 – 103.259 mm 4.0646 – 4.0653 in
Cylinder bore out-of-round limit Engine Block Not separately spec'd
Cylinder bore taper limit Engine Block Not separately spec'd
Piston diameter (skirt) Piston 103.258 – 103.289 mm 4.0653 – 4.0665 in
Piston-to-bore clearance Piston -0.048 – 0.001 mm -0.0019 – 0 in 0.055 mm
Piston ring end gap (top compression) Piston Rings 0.17 – 0.38 mm 0.0067 – 0.015 in 0.17 – 0.44 mm
Piston ring end gap (second compression) Piston Rings 0.32 – 0.63 mm 0.0126 – 0.0248 in 0.32 – 0.69 mm
Piston ring end gap (oil rail) Piston Rings 0.22 – 0.79 mm 0.0086 – 0.0311 in 0.22 – 0.85 mm
Piston ring side clearance (top) Piston Rings 0.03 – 0.083 mm 0.0012 – 0.0033 in
Piston ring side clearance (second) Piston Rings 0.04 – 0.083 mm 0.0016 – 0.0033 in
Cylinder head deck warpage limit Cylinder Head 0.08 mm 0.003 in
Valve stem-to-guide clearance (intake) Cylinder Head 0.025 – 0.066 mm 0.001 – 0.0026 in 0.093 mm
Valve stem-to-guide clearance (exhaust) Cylinder Head 0.025 – 0.066 mm 0.001 – 0.0026 in 0.093 mm
Valve seat width (intake) Cylinder Head 1.02 mm 0.04 in
Valve seat width (exhaust) Cylinder Head 1.78 mm 0.07 in
Valve face angle Valve 45°
Valve seat angle Cylinder Head 46°
Valve spring installed height Valve Spring 45.75 mm 1.8 in
Valve spring seat pressure (valve closed) Valve Spring 400 N (90 lbf) 90 lbf
Valve spring open pressure (at full lift) Valve Spring 1175 N (264 lbf) 264 lbf
Valve lash Valvetrain Not separately spec'd
Engine oil pressure at idle (hot) Lubrication 165 kPa (24 psi) 24 psi
Engine oil pressure at rated rpm (hot) Lubrication 262 kPa (38 psi) 38 psi

A handful of measurements (cylinder bore out-of-round and taper, main journal runout, valve lash) are not published as discrete limits by GM for this engine. We document each one, explain what bounds it, and note the accepted service practice on its detail page rather than invent a number.