955752 Volvo.Penta Screw, 3/4-UNF

Illustration 1 g00606851
Type 1 and Type 4
(A) Standard valve spring
(B) Standard valve spring
Illustration 2 g00582475
Type 2 and Type 3
(A) Longer valve spring
(B) Standard valve spring
Illustration 3 g00582514
(A) Inside diameter of valve seat insert
(X) Distance from valve head to cylinder head face
Table 1
Differences of the Cylinder Head Valves
Type 1 Type 2 Type 3 Type 4
Inlet Valve Spring Standard Standard Standard Standard
Valve Seat Standard Standard Smaller ID Smaller ID
Maximum (X) 2.05 mm (0.081 inch) 2.05 mm (0.081 inch) 2.05 mm (0.081 inch) 2.05 mm (0.081 inch)
Minimum (X) 1.13 mm (0.045 inch) 1.13 mm (0.045 inch) 1.13 mm (0.045 inch) 1.13 mm (0.045 inch)
Exhaust Valve Spring Standard Longer Longer Standard
Valve Seat Standard Standard Standard Standard
Maximum (X) 2.85 mm (0.112 inch) 2.85 mm (0.112 inch) 2.85 mm (0.112 inch) 2.85 mm (0.112 inch)
Minimum (X) 1.50 mm (0.059 inch) 1.50 mm (0.059 inch) 1.50 mm (0.059 inch) 1.50 mm (0.059 inch) Type 1 Cylinder Head
Note: Type 1 cylinder heads have standard valve springs and valve seat inserts. Type 2 cylinder heads have longer exhaust valve springs and standard valve seat inserts. Type 3 cylinder heads have longer exhaust valve springs. The inlet valve seat inserts have smaller inside diameters. Type 4 cylinder heads have standard valve springs. The inlet valve seat inserts have smaller inside diameters.
Illustration 4 g00581757Note: The inlet and exhaust valve stems must be coated with engine oil prior to installation in the cylinder head.Note: The tips of the inlet and exhaust valves must be coated with 8T-2998 Lubricant . The lubricant must be applied after assembly of the retainer. (1) Exhaust valve (2) Inlet valve (3) 7C-4273 Spring for inlet valve and Spring for exhaust valve Free length ... 71.0 mm (2.80 inch)Assembled length ... 65.9 mm (2.60 inch)Load at assembled length ... 217 22 N (49 5 lb)Minimum operating length ... 51.0 mm (2.01 inch)Load at minimum operating length ... 858 43 N (193 10 lb) (4) Seal (5) Height to the top of the valve guides ... 23.00 0.50 mm (0.906 0.020 inch)Diameter of valve guide ... 12.065 mm (0.4750 inch)Note: Install the valve guide from the spring side of the cylinder head. The 12.065 mm (0.4750 inch) diameter on the valve guide should be protruding from the spring side of the cylinder head.Note: Assemble the valve guide. Seat the seal against the top of the valve guide. (6) Valve stem diameter ( new) ... 8.000 0.008 mm (0.3150 0.0003 inch)The cylinder head valves can be reused if the minimum dimensions for the valve stems are met.Minimum diameter of a valve stem ( worn) ... 7.965 mm (0.3136 inch)After installation into the cylinder head, the valve guide bore is the following value.Diameter of the valve guide bore ( new) ... 8.054 0.026 mm (0.3171 0.0010 inch)The valve guide can be reused. The valve guide bore must not be larger than the following value.Maximum diameter of a valve guide bore ( worn) ... 8.130 mm (0.3201 inch) (7) Diameter of the valve head Inlet valve ... 47.00 0.13 mm (1.850 0.005 inch)Exhaust valve ... 40.00 0.13 mm (1.575 0.005 inch) (8) Angle of the valve faces Inlet valve ... 29.75 0.25 degreesExhaust valve ... 45.00 0.25 degrees
Illustration 5 g00581805 (9) Outside diameter of the valve seat inserts Inlet valve ... 50.000 0.013 mm (1.9685 0.0005 inch)Exhaust valve ... 43.000 0.013 mm (1.6929 0.0005 inch)Diameter of the bore in cylinder head for the valve seat insertBore diameter Inlet valve ... 49.931 0.013 mm (1.9658 0.0005 inch)Exhaust valve ... 42.931 0.013 mm (1.6902 0.0005 inch) (10) Inside diameter of valve seat inserts Inlet valve ... 43.29 0.13 mm (1.704 0.005 inch)Exhaust valve ... 37.00 0.13 mm (1.457 0.005 inch)