Type 1 Engines and 9RM Engines
Note: For a complete description of Type 1 and Type 2 engines, refer to the Specifications Module, "Engine Design" for more information.
Illustration 1 | g00295711 |
Piston and rings |
Note: The word "Front" or an arrow which is marked on the piston crown must be toward the front of the engine. If the piston crown is not marked, put the narrowest side of the piston crater toward the side of the engine with the fuel injection pump. The shortest distance between the edge of the piston crater and the edge of the piston is the narrowest side of the piston crater.
Note: Be sure that the ring end gaps of all the piston rings have 120 degrees spacing from each other.
Note: Refer to Systems Operation, "General Information" for the location of the serial number.
(1) Width of groove in piston for top ring ...
Thickness of top ring ...
Clearance between groove and piston ring ...
Clearance between the ends of the top ring with a cylinder liner without any wear ...
(2) Width of groove in piston for intermediate ring ...
Thickness of intermediate ring ...
Clearance between groove and intermediate ring ...
Clearance between the ends of the intermediate ring with a cylinder liner without any wear ...
(3) Width of groove in piston for oil control ring ...
Thickness of oil control ring ...
Clearance between groove and oil control ring ...
Clearance between the ends of oil control ring with a cylinder liner without any wear ...
(4) Diameter of new piston pin ...
Bore for piston pin ...
(1) Shape of groove in piston for top ring ... Taper
Shape of top ring ... Taper
Clearance between the ends of top ring in a cylinder liner without any wear ...
(2) Width of groove in piston for intermediate ring ...
Thickness of intermediate ring ...
Clearance between groove and intermediate ring ...
Clearance between the ends of an intermediate ring in a cylinder liner without any wear ...
(3) Width of groove in piston for oil control ring ...
Thickness of oil control ring ...
Clearance between groove and oil control ring ...
Clearance between the ends of an oil control ring in a cylinder liner without any wear ...
(4) Diameter of new piston pin ...
Bore for piston pin ...
Illustration 2 | g00891532 |
Quadram piston |
There are two different designs for the crown of the piston. One design is the Quadram piston. There is only one grade of piston for the replacement of a Quadram piston.
Grade of piston for service ... L
Height of a Quadram piston above the top face of the cylinder block ...
Illustration 3 | g00891548 |
Fastram piston |
The other style of piston is the Fastram piston. The piston height above the top face of the cylinder block is controlled by different grades of height of the piston. Identification of the height grade is by the letter that is stamped on the top of each piston. The height grade can be checked by measuring from the center of the piston pin to the top of the piston. The difference between each grade of height is
Height Grades for the Piston | ||
Letter on top of Piston | Height Dimension | Latest Equivalent Grade |
A(1) | |
G |
B(1) | |
H |
C(1) | |
J |
D(1) | |
K |
E(1) | |
L |
F | |
- |
G | |
- |
H | |
- |
J | |
- |
K | |
- |
L | |
- |
(1) | Earlier engines |
Height of a Fastram piston above the top face of the cylinder block ...
Type 2 Engines and 7BJ Engines
Note: For a complete description of Type 1 and Type 2 engines, refer to the Specifications Module, "Engine Design" for more information.
Illustration 4 | g00500921 |
Note: The word "Front" or an arrow which is marked on the piston crown must be toward the front of the engine. If the piston crown is not marked, put the narrowest side of the piston crater toward the side of the engine with the fuel injection pump. The shortest distance between the edge of the piston crater and the edge of the piston is the narrowest side of the piston crater.
Note: Be sure that the ring end gaps of all the piston rings have 120 degrees spacing from each other.
Note: Refer to Systems Operation, "General Information" for the location of the serial number.
(1) Top piston ring
- Shape of groove in piston for top ring ... Taper
- Shape of top ring ... Taper
- Clearance between the ends of the top ring in a cylinder liner without any wear ...
0.28 to 0.63 mm (.011 to .025 inch) - Shape of top ring ... Taper
Note: Install the word "TOP" toward the top of the piston. New top rings have a red identification mark which must be on the left of the ring gap when the intermediate ring is installed on an upright piston.
(2) Intermediate ring
- Width of groove in piston for intermediate ring ...
2.56 to 2.58 mm (0.101 to 0.102 inch) - Thickness of intermediate ring ...
2.48 to 2.49 mm (0.097 to 0.098 inch) - Clearance between groove and intermediate ring ...
0.07 to 0.11 mm (.003 to .004 inch) - Clearance between the ends of an intermediate ring in a cylinder liner without any wear ...
0.40 to 0.65 mm (.016 to .026 inch) - Thickness of intermediate ring ...
Note: Install the word "TOP" toward the top of the piston. New intermediate rings have a green identification mark which must be on the left of the ring gap when the intermediate ring is installed on an upright piston.
(3) Oil control ring
- Width of groove in piston for oil control ring ...
3.54 to 3.56 mm (.139 to .140 inch) - Thickness of oil control ring ...
3.47 to 3.49 mm (.136 to .137 inch) - Clearance between groove and oil control ring ...
0.05 to 0.09 mm (.002 to .004 inch) - Clearance between the ends of an oil control ring in a cylinder liner without any wear ...
0.38 to 0.83 mm (.015 to .033 inch) - Thickness of oil control ring ...
Note: A pin is used in order to hold both ends of the spring of the oil control ring in position. The ends of the spring of the oil control ring must be 180 degrees opposite the end gap of the oil control ring.
(4) Diameter of new piston pin ...
Bore for piston pin ...
Piston height above cylinder block (not shown) ...