Piston Fitting

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Fig 1: Dundee Engine Block Main Bearing Journal Diameter Grade Markings Location

Courtesy of CHRYSLER GROUP, LLC

The pistons are "select fit" to achieve proper oil clearance. On Dundee Engine Plant (DEP) engine blocks the cylinder bore diameter grade markings (1) are etched on the right face of the engine block near the intake manifold.

Fig 2: Engine Block Cylinder Bore Diameter Grade Markings

Courtesy of CHRYSLER GROUP, LLC

DUNDEE ENGINE BLOCK ETCHING EXAMPLE BCAB

These marks are read from front to rear (right to left) corresponding with cylinder number 1, 2, 3, 4. Cylinder number one is B, cylinder number 2 is A, cylinder number three is C.

Fig 3: Termoli Engine Block Barcode Example

Courtesy of CHRYSLER GROUP, LLC

On Termoli built engine blocks the cylinder bore diameter grade markings are on a label affixed to the rear face of the block (1).

Fig 4: Termoli Engine Identification Label

Courtesy of CHRYSLER GROUP, LLC

TERMOLI ENGINE BLOCK BARCODE EXAMPLE BCAB

These marks are read from left to right, corresponding with cylinder number 1, 2, 3, 4. Cylinder number one is B, cylinder number 2 is C, cylinder number three is A. Engine block cylinder bore diameter grade markings correspond to specific cylinder bore diameters. The chart below identifies the three engine block grade markings and their associated cylinder bore diameters.

Engine Block Marking	Cylinder Bore Size mm (in.)
Engine Block Marking	Metric	Standard
A	72.000 - 72.010 mm	2.8346 - 2.8350 in.
B	72.010 - 72.020 mm	2.8350 - 2.8354 in.
C	72.020 - 72.030 mm	2.8354 - 2.8358 in.

Fig 5: Piston Size Mark

Courtesy of CHRYSLER GROUP, LLC

The piston is marked with the piston size (1) on the piston crown. The pistons are available in three different sizes in order to achieve the desired oil clearance. Select the piston size that corresponds to the engine block cylinder bore diameter grade markings for each cylinder.

Pistons are available in three sizes. The chart below identifies the three piston sizes.

Piston Marking	Piston Size mm (in.)
Piston Marking	Metric	Standard
A	71.960 - 71.970 mm	2.8331 - 2.8835 in.
B	71.970 - 71.980 mm	2.8835 - 2.8339 in.
C	71.980 - 71.990 mm	2.8339 - 2.8342 in.

Fig 6: Identifying Coating Material On Piston

Courtesy of CHRYSLER GROUP, LLC

NOTE:

Typical coated piston shown in illustration.

The coated pistons are serviced with the piston pin and connecting rod pre-assembled. The coating material (1 and 2) is applied to the piston after the final piston machining process. Piston installation into the cylinder bore requires slightly more pressure than that required for non-coated pistons. The bonded coating on the piston will give the appearance of a line-to-line fit with the cylinder bore.