816248 Mercruiser SEAWATER PUMP ASSEMBLY

Illustration 1 g00294082
(1) Single valve springs Length under test force ... 39.0 mm (1.54 inch) Test force ... 136 to 154 N (31 to 35 lb) (2) Valve spring seat insert for the valve spring (3) Valve guides Inside diameter ... 9.000 to 9.022 mm (0.3542 to 0.3552 inch) Outside diameter of inlet valve guide ... 13.034 to 13.047 mm (0.5131 to 0.5137 inch) Outside diameter of exhaust valve guide ... 14.034 to 14.047 mm (0.5525 to 0.5530 inch) Bore diameter in the cylinder head for the inlet valve guide ... 13.000 to 13.027 mm (0.5118 to 0.5128 inch) Bore diameter in the cylinder head for the exhaust valve guide ... 14.000 to 14.027 mm (0.5512 to 0.5522 inch) Interference fit of valve guide in the cylinder head ... 0.007 to 0.047 mm (0.0003 to 0.0019 inch) Overall length of inlet and exhaust valve guides ... 51.25 mm (2.018 inch) Projection of valve guide above valve spring recess (2) ... 14.85 to 15.15 mm (0.585 to 0.596 inch)Note: When new valve guides are installed, new valves and new valve seat inserts must be installed. The valve guides and the valve seat inserts are supplied as partially finished parts. The unfinished valve guides and unfinished valve seat inserts are installed in the cylinder head. Then, the guides and inserts are cut and reamed in one operation with special tooling. This procedure ensures the concentricity of the valve seat to the valve guide in order to create a seal that is tight. Refer to the Disassembly and Assembly Manual for removal and installation procedures. (4) Diameter of the exhaust valve stem ... 8.938 to 8.960 mm (0.3519 to 0.3528 inch)Clearance of exhaust valve in valve guide ... 0.040 to 0.084 mm (0.0016 to 0.0033 inch)Maximum permissible clearance of exhaust valve in valve guide ... 0.104 mm (0.0041 inch)Overall length of the exhaust valve ... 123.75 to 124.40 mm (4.872 to 4.897 inch) (5) Diameter of the inlet valve stem ... 8.953 to 8.975 mm (0.3525 to 0.3533 inch)Clearance of inlet valve in valve guide ... 0.025 to 0.069 mm (0.0010 to 0.0027 inch)Maximum permissible clearance of inlet valve in valve guide ... 0.089 mm (0.0035 inch)Overall length of the inlet valve ... 123.75 to 124.40 mm (4.872 to 4.897 inch) (6) Angle of exhaust valve face ... 45 degreesNote: Some engines may have valve face angles of 30 degrees. (7) Diameter of the exhaust valve head ... 41.88 to 42.12 mm (1.649 to 1.658 inch)Valve depth below the cylinder head face Minimum ... 0.40 mm (0.016 inch) Maximum ... 0.60 mm (0.024 inch) Service wear limit ... 0.805 mm (0.032 inch) (8) Diameter of the inlet valve head ... 44.88 to 45.12 mm (1.776 to 1.767 inch)Valve depth below the cylinder head face Minimum ... 0.40 mm (0.016 inch) Maximum ... 0.60 mm (0.024 inch) Service wear limit ... 0.805 mm (0.032 inch) (9) Angle of inlet valve face ... 45 degreesNote: Some engines may have valve face angles of 30 degrees.The valve lash is the following value when the engine is hot or cold. Inlet valves ... 0.20 mm (0.008 inch) Exhaust valves ... 0.45 mm (0.018 inch)
Illustration 2 g00900678
(10) Machine the recess in the head for valve seat inserts to the following dimensions.Inlet (A) ... 10.585 to 10.715 mm (0.4167 to 0.4219 inch) (B) ... 48.035 to 48.060 mm (1.8911 to 1.8921 inch) (C) Maximum radius ... 0.38 mm (0.015 inch)Exhaust (A) ... 10.585 to 10.715 mm (0.4167 to 0.4219 inch) (B) ... 44.035 to 44.060 mm (1.7336 to 1.7346 inch) (C) Maximum radius ... 0.38 mm (0.015 inch)Note: When a new valve seat insert is installed, a new valve and valve guide must be installed. Refer to the Disassembly and Assembly Manual for removal and installation procedures.
Illustration 3 g00900679
(11) Valve seat insert Valve seat angle (exhaust) ... 46 degrees Valve seat angle (inlet) ... 46 degreesNote: Some engines may have valve seats with an angle of 31 degrees. (D) Included angle of the faces of the valve seat insert Engines with 46 degree valve seats ... 88 degrees Engines with 31 degree valve seats ... 118 degrees (E) Dimension of chamfer for all engines ... 0.9 to 1.3 mm (0.035 to 0.051 inch) (F) Angle of chamfer from the vertical for all engines ... 30 degrees