PISTONS, RINGS, & CONNECTING RODS

PISTONS, RINGS, & CONNECTING RODS

Remove Piston and Connecting Rod

1.Carefully remove any carbon or ridge at top of cylinder bore to prevent ring breakage.

2.Remove rod bolts and connecting rod cap (A, Figure 1).

3.Push piston and rod assembly out through top of cylinder bore.

Figure 1

Disassemble

1.Rotate pin retainer until one end is exposed in notch in pin bore.

2.Remove the two retainer pins (A, Figure 2) with needle nose pliers.

NOTE: Some pistons have a shoulder stop on one side and a single retainer.

3.Slide out pin (B) from opposite side and remove connecting rod from piston.

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Figure 2

4.Using Piston Ring Expander #19340 (Figure 3), remove rings one at a time. Note the order and orientation of the rings before removal.

Figure 3

NOTE: Some oil control rings consist of two thin steel rails and a spring expander. These must be removed by hand as follows:

Grasp one end of the upper steel rail and wind the rail from the oil ring groove into the center ring groove. Repeat into the top ring groove and then off the piston.

Remove the spring expander, then remove the lower steel rail.

Inspect

Check Piston and Pin

1.Inspect piston for scoring, galling, or other damage. Replace piston if necessary.

2.Using a dial caliper or plug gauge, measure the pin bore diameter. Compare with reject dimensions listed in Section 12 - Engine Specifications. If pin bore exceeds reject dimensions, replace the piston.

3.Measure outside diameter of pin and compare to the reject dimension listed in Section 12 - Engine Specifications. If pin is smaller that the reject dimension, replace the pin.

4.Clean carbon from top ring groove.

5.Place NEW ring in groove (Figure 4) and, using a feeler gauge, measure space between ring and ring land. Compare with reject dimensions listed in Section 12 -

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Briggs & Stratton 270962, 271172 Pistons, Rings, & Connecting Rods, Remove Piston and Connecting Rod, Disassemble, Inspect