Engine Block: Diagnosis Honda S2000 AP1

Inspection

Note. Inspect the piston, piston pin, and connecting rod when they are at room temperature.

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1. Measure the diameter of the piston pin. Piston Pin Diameter Standard (New): 22.961-22.965 mm (0.9040-0.9041 in.) Service Limit: 22.953 mm (0.9037 in.)
2. Zero the dial indicator to the piston pin diameter.
3. Check the difference between the piston pin diameter and piston pin hole diameter in the piston. Piston Pin-to-Piston Clearance Standard (New): -0.002 to +0.005 mm (-0.00008 to +0.00020 in.) Service Limit: 0.010 mm (0.0004 in.)
4. Measure the piston pin-to-connecting rod clearance. NOTE: When replacing the connecting rod, also replace the piston pin as a set. Piston Pin-to-Connecting Rod Clearance Standard (New): 0.018-0.035 mm (0.0007-0.0014 in.) Service Limit: 0.04 mm (0.0016 in.)

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1. Install a new piston pin snap ring (A) only on one side.
2. Coat the piston pin bore in the piston and the connecting rod, and the piston pin with new engine oil.
3. Heat the piston to about 158 °F (70 °C).
4. Install the piston pin (A). Assemble the piston (B) and connecting rod (C) with the "IN" mark (D) and the reference mark (E) on the same side.
5. Install the remaining new snap ring (F).
6. Turn the snap rings in the ring grooves until the end gaps are positioned at the bottom of the piston.

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1. Remove the piston from the engine block (see «OIL PAN REMOVAL»(ref-221323-S25540807762006022400000) ).
2. Using a ring expander (A), remove the old piston rings (B).
3. Clean all ring grooves thoroughly with a squared-off broken ring or ring groove cleaner with a blade to fit the piston grooves. The top and second ring grooves are 1.2 mm (0.05 in.) wide. The oil ring groove is 2.0 mm (0.08 in.) wide. File down a blade if necessary. Do not use a wire brush to clean the ring grooves, or cut the ring grooves deeper with the cleaning tools. NOTE: If the piston is to be separated from the connecting rod, do not install new rings yet.
4. Using a piston, push a new ring (A) into the cylinder bore 15-20 mm (0.6-0.8 in.) from the bottom.
5. Measure the piston ring end-gap (B) with a feeler gauge: If the gap is too small, check to see if you have the proper rings for your engine. If the gap is too large, recheck the cylinder bore diameter against the wear limits (see «BLOCK AND PISTON INSPECTION»(ref-221323-S10426735142006022400000) ). If the bore is over the service limit, the engine block must be rebored. Piston Ring End-Gap Top Ring: Standard (New): 0.25-0.35 mm (0.010-0.014 in.) Service Limit: 0.60 mm (0.024 in.) Second Ring: Standard (New): 0.60-0.75 mm (0.024-0.030 in.) Service Limit: 0.90 mm (0.035 in.) Oil Ring: Standard (New): 0.20-0.70 mm (0.008-0.028 in.) Service Limit: 0.80 mm (0.031 in.)
6. Install the rings as shown. The top ring (A) has a R1 mark and the second ring (B) has a R2 mark. The manufacturing marks (C) must be facing upward.
7. Rotate the rings in their grooves to make sure they do not bind.
8. Position the ring end gaps as shown
9. After installing a new set of rings, measure the ring-to-groove clearances: Top Ring Clearance Standard (New): 0.045-0.090 mm (0.0018-0.0035 in.) Service Limit: 0.135 mm (0.005 in.) Second Ring Clearance Standard (New): 0.040-0.070 mm (0.0016-0.0028 in.) Service Limit: 0.13 mm (0.005 in.)

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1. Set the crankshaft to bottom dead center (BDC) for each cylinder.
2. Apply new engine oil to the piston, inside the ring compressor, and the cylinder bore. Then attach the ring compressor to the piston.
3. Remove the connecting rod caps, then check that the bearing is securely in place.
4. Position the arrow (A) facing the cam chain side of the engine.
5. Position the piston in the cylinder, and tap it in using the wooden handle of a hammer (A). Maintain downward force on the ring compressor (B) to prevent the rings from expanding before entering the cylinder bore.
6. Stop after the ring compressor pops free, and check the connecting rod-to-crank journal alignment before pushing the piston into place.
7. Check the connecting rod bearing clearance with plastigauge (see «CONNECTING ROD BEARING REPLACEMENT»(ref-221323-S35206234692006022400000) ).
8. Apply new engine oil to the threads of the connecting rod bolts.
9. Install the rod caps with bearings, then tighten the connecting rod bolts is sequence to 25 N.m (2.5 kgf.m, 18 lbf.ft).
10. Tighten the connecting rod bolts an additional 90 °.

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1. Apply new engine oil to the piston, inside the ring compressor, and the cylinder bore. Then attach the ring compressor to the piston.
2. Remove the connecting rod caps, then check that the bearing is securely in place.
3. Position the arrow (A) facing the cam chain side of the engine.
4. Position the piston in the cylinder, and tap it in using the wooden handle of a hammer (A). Maintain downward force on the ring compressor (B) to prevent the rings from expanding before entering the cylinder bore.
5. Position all pistons at top dead center.