Generac Power Systems 941-2, 940-2 Connecting Rod, Assembly And Installation, Ring End Gap

Section 2.3

PISTON, RINGS, CONNECTING ROD

Figure 7. Ring Locations in Piston Grooves

CHECKING PISTON RING END GAP:

To check piston rings end gap, proceed as follows (see Figure 8):

1.Locate a point inside the cylinder that is 2.75 inches (70mm) down from top of cylinder. This is approximately half-way down.

2.Place the ring into the cylinder. Use the piston to push the ring squarely into the cylinder to the proper depth.

3.Use a feeler gauge to measure the ring end gap. If end gap is excessive, rebore the cylinder to take oversize parts.

TOP RING END GAP (GV-220)

DESIGN GAP: 0.005-0.016 inch (0.15-0.40mm) WEAR LIMIT: 0.024 inch (0.60mm) Maximum

SECOND RING END GAP (GV-220)

DESIGN GAP: 0.006-0.016 inch (0.15-0.40mm) WEAR LIMIT: 0.024 inch (0.60mm) Maximum

OIL RING END GAP (GV-220)

DESIGN GAP: 0.015-0.055 inch (0.38-1.40mm) WEAR LIMIT: 0.062 inch (1.60mm) Maximum

Figure 8. Ring End Gap

CONNECTING ROD

The connecting rod is manufactured of die cast alu- minum. Alignment marks are provided on the rod and on the connecting rod cap. Be sure to align these marks when assembling the rod to the crankshaft. Connecting rod bolts are of the "washerless" type.

The connecting rod and the connecting rod cap are a matched set and must be replaced as a matched set.

Figure 9. Connecting Rod

ASSEMBLY AND INSTALLATION

ASSEMBLY:

Use a ring expander when installing rings into the pis- ton ring grooves. Install the OIL RING ASSEMBLY first. Then, install the second compression ring with its Inside chamfer facing up. Finally, install the top compression ring.

When assembling the piston, connecting rod and wrist pin, the assembly marks on the piston must be toward the flywheel side of the engine.

Coat the wrist pin, wrist pin bore in piston, and wrist pin bore in the rod with engine oil. Install one snap ring into the piston's wrist pin bore. Then, assemble the piston to the rod. Slide the wrist pin through one piston bore, through the rod bore, and through the second piston bore until it contacts the snap ring. Then, install the second snap ring into the piston bore.

INSTALLATION:

Coat the cylinder walls with engine oil, as well as the crank throw, connecting rod bearing and connecting rod cap bearing. Then, install the rod and piston assembly as follows:

1.Use a ring compressor to compress the rings into the piston ring grooves. MAKE SURE ALL RINGS ARE FULLY COM-

PRESSED INTO THEIR GROOVES.

2.Guide the connecting rod into the cylinder, with assembly mark on piston toward the flywheel side of engine.

3.When the ring compressor contacts top of cylinder, use a wood

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