Engine Mechanical (3.4L V6): Overhaul Toyota 4Runner III

Piston & Rod Assembly

1. Ensure connecting rod and connecting rod cap are marked with matching cylinder number for installation reference. Piston and connecting rod must be installed in cylinder block with front mark facing timing belt end of engine. (Scheme 66)
2. Before disassembling piston and connecting rod, try to move piston back and forth on piston pin. Replace piston and piston pin as an assembly if any movement is felt.
3. When removing piston from connecting rod, remove snap rings from piston. Heat piston to 140°F (60°C) in water. Remove piston pin. Separate piston from connecting rod.
4. Different piston sizes are used. Piston diameter is determined by size mark ("1", "2" or "3") stamped on top of piston. (Scheme 66) Measure piston skirt diameter at 1.02" (25.9 mm) from top of piston at 90-degree angle to piston pin. Ensure piston diameter is within specification. See «PISTONS, PINS & RINGS»(ref-8778-S08151175252000092200000) and «CYLINDER BLOCK»(ref-8778-S02080623672000092200000) tables under ENGINE SPECIFICATIONS.
5. Ensure piston pin diameter is within specification. See «PISTONS, PINS & RINGS»(ref-8778-S08151175252000092200000) table under ENGINE SPECIFICATIONS. Ensure connecting rod piston pin bushing bore diameter, bend and twist are within specification. See «CONNECTING RODS»(ref-8778-S15489807582000092200000) table under ENGINE SPECIFICATIONS.
6. Piston pin bushing may be replaced in connecting rod if bore diameter is not within specification. Use press and bushing remover/installer to replace bushing.
7. Ensure bushing oil hole aligns with connecting rod oil hole. Hone bushing to obtain correct piston pin-to-rod clearance. See «PISTONS, PINS & RINGS»(ref-8778-S08151175252000092200000) table under ENGINE SPECIFICATIONS.
8. Ensure nut rotates easily on connecting rod bolt. If nut does not rotate easily, use caliper to measure outside diameter of connecting rod bolt at threaded area.59" (14.9 mm) from end of connecting rod bolt. Replace connecting rod with connecting rod bolt and nut as an assembly if outside diameter is less than.2992" (7.599 mm).
9. To reassemble, install NEW snap ring in piston. Ensure ends of snap ring are not aligned with piston pin cutout area of piston. Install piston on connecting rod with front mark (cavity) on top of piston aligned with front mark on connecting rod. (Scheme 66)
10. Coat piston pin with engine oil. Gradually heat piston to 140°F (60°C) in water. Install piston pin in piston and connecting rod. Install remaining NEW snap ring. Ensure ends of snap ring are not aligned with piston pin cutout area of piston.

Scheme 66