Measuring cylinder bores (Mazda Capella GD)

To measure the cylinder bores, a dial indicator is required (figure 81). with which you can measure the inside and bottom of the hole. If there is no pointer indicator, then subsequent work cannot be carried out.



Measurements of cylinder bores are taken in longitudinal and transverse directions. In addition, you need to take measurements 10 mm before the top edge, 10 mm before the bottom edge, and one in the middle. If necessary, make 6 measurements per cylinder hole. Compare all obtained values with the data in the table of parameters and dimensions. Make sure that all cylinders have bores even if only one cylinder is not within the specified dimensions. A deviation of 0.15 mm from the specified dimensions means that the cylinder must be ground.

The difference between the upper and lower dimensions or between the transverse and longitudinal dimensions cannot be more than 0.019 mm for a gasoline engine or 0.022 for a diesel engine. Oversized pistons for individual engines have:

• F6 motor: 0.25, 0.50, 0.75 and 1.00 mm
• FE motor: 0.25 and 0.50 mm
• DOHC engine: 0.25 and 0.50 mm
• Diesel engine: 0.25 and 0.50 mm

The cylinder bore end size is determined by the pistons being measured by diameter. For all petrol engines, the measurement is taken exactly 18 mm below the lowest piston ring groove, as shown in the figure 82. In a diesel engine, in contrast, the measurement is taken 19 mm above the lower edge of the piston as shown in the figure 83. To the obtained dimensions, you need to add the working clearance of the pistons of 0.036-0.075 mm for a gasoline engine or 0.032-0.060 mm for a diesel engine. In addition, a 0.02mm addition is provided for final honing.







To check the working clearance of the pistons and cylinder bores, take measurements as described and determine the difference between the dimensions for each cylinder. If the result is more than 0.15 mm, the cylinders need to be ground, since the working clearance has reached the wear limit.