Generac — Piston and Connecting Rod Assembly Removal and Installation

Repair & overhaul · Piston and rod assembly

From a Generac service manual covering: CAC478, CAC480, SQR480. Check it applies to your exact model before use.

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Procedure

1. Rotate the crankshaft to bring the cylinder to bottom dead center; check and mark the connecting rod and cap.
2. Remove the connecting rod bolts and rod cap; label the upper and lower halves.
3. Push the connecting rod and piston out of the cylinder with a hammer wood handle.
4. Remove the piston ring with a special tool or feeler gauge piece and label each cylinder.
5. Press the piston pin out of the piston hole and connecting rod small end with a press.
6. Clean carbon deposits from piston, rings, pin and upper cylinder bore.
7. Measure cylinder bore diameter and piston diameter.
8. Heat the connecting rod small end to 230°—400°C and apply SAE50 engine oil or graphite colloid oil.
9. Press the piston pin into the connecting rod small end and piston pin hole.
10. Apply engine oil, stagger ring gaps 120° and install the piston and rod assembly into the cylinder bore.
11. Mount the connecting rod cap and retain with two elastic retaining pins.
12. Tighten connecting rod bolts to 30—36Nm.

Source: Generac service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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