Engine Block: Diagnosis Acura MDX II facelift

Inspection

Note. Inspect the piston, the piston pin, and the 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): 21.961-21.965 mm (0.86460-0.86476 in) Service Limit: 21.954 mm (0.86433 in)
2. Zero the gauge (A) to the piston pin diameter.
3. Check the difference between the piston pin diameter and piston pin hole diameter on the piston. Piston Pin-to-Piston Clearance Standard (New): -0.0050-0.0030 mm (-0.000197-0.000118 in) Service Limit: 0.004 mm (0.00016 in)
4. Measure the piston pin-to-connecting rod clearance. Piston Pin-to-Connecting Rod Clearance Standard (New): 0.005-0.015 mm (0.00020-0.00059 in) Service Limit: 0.019 mm (0.00075 in)

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1. Install a piston pin snap ring (A) only on one side.
2. Coat the piston pin bore in the piston, the bore in the connecting rod, and the piston pin with new engine oil.
3. Heat the piston to about 158 CF (70°C).
4. Assemble the piston (A) and the connecting rod (B) with the embossed marks (C) on the same side. Install the piston pin (D). NOTE: Apply new engine oil to the piston pin.
5. Install the remaining snap ring.
6. Reassemble the other pistons the same way.

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1. Remove the pistons from the engine block (see «CRANKSHAFT AND PISTON REMOVAL»(ref-510471-S21413533192012102300000) ).
2. Using a ring expander (A), remove the aid piston rings (B).
3. Clean all the ring grooves thoroughly with a squared-off broken ring, or a ring groove cleaner with a blade to fit the piston grooves. File down the blade, if necessary. The top ring and second ring grooves are 1.2 mm (0.05 in) wide, and the oil ring groove is 2.8 mm (0.11 in) wide. Do not use a wire brush to clean the ring grooves, or cut the ring grooves deeper with the cleaning tool. 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 step 5 under «Block and Piston Inspection»(ref-510471-S13908183532012102300000) ). Piston Ring End-Gap Top Ring: Standard (New): 0.30-0.40 mm (0.012-0.015 in) Service Limit: 0.60 mm (0.023 in) Second Ring: Standard (New): 0.40-0.55 mm (0.016-0.021 in) Service Limit: 0.70 mm (0.027 in) Oil Ring: Standard (New): 0.20-0.35 mm (0.008-0.013 in) Service Limit: 0.80 mm (0.031 in)
6. Install the rings as shown. The top ring (A) has a 1E mark and the second ring (B) has a 2E mark. The manufacturing marks (C) must face upward.
7. After installing a new set of rings, measure the ring-to-groove clearance. Top Ring Clearance Standard (New): 0.055-0.085 mm (0.003-0.003 in) Service Limit: 0.15 mm (0.005 in) Second Ring Clearance Standard (New): 0.030-0.060 mm (0.002-0.002 in) Service Limit: 0.13 mm (0.005 in)
8. Rotate the rings in their grooves to make sure they do not bind.
9. Position the ring end gaps as shown