Acura 13210-PR4-A00 Engine Connecting Rod

Before the inspection process can be carried out, the piston/connecting rod assemblies must be cleaned and the original piston rings removed from the pistons, ensuring that new piston rings are always used during reassembly. Using a piston ring expander tool, carefully remove the rings from the pistons without nicking or gouging them. Scrape all traces of carbon from the top of the piston using a handheld wire brush or fine emery cloth after the majority of deposits have been removed, avoiding the use of a wire brush mounted in a drill motor to prevent erosion of the soft piston material. A piston ring groove cleaning tool should be used to remove carbon deposits from the ring grooves, or a piece broken off the old ring can serve as an alternative, taking care not to remove any metal or damage the grooves. After removing deposits, clean the piston/rod assemblies with solvent and dry them with compressed air, wearing eye protection and ensuring that the oil return holes in the ring grooves are clear. If the pistons and cylinder walls are not excessively damaged or worn, and the engine block is not rebored, new pistons may not be necessary, although new piston rings should always be used during a rebuild. Each piston should be carefully inspected for cracks, scoring, scuffing, holes, and burned areas, as these can indicate overheating or abnormal combustion, necessitating a thorough check of the cooling and lubrication systems. Corrosion in the form of small pits suggests coolant leakage into the combustion chamber or crankcase, which must be addressed to prevent recurrence in the rebuilt engine. Measure the piston ring side clearance by placing a new piston ring in each groove and using a feeler gauge, checking at several points around the groove, and ensuring the correct ring is used for each groove. The piston-to-bore clearance should be checked by measuring the bore and piston diameter, ensuring they are correctly matched, and calculating the clearance by subtracting the piston diameter from the bore diameter; if the clearance exceeds specifications, rebore the block and install new pistons and rings. Piston-to-rod clearance should be assessed by twisting the piston and rod in opposite directions, with any noticeable play indicating excessive wear that requires correction, potentially involving resizing at an automotive machine shop. If pistons need to be removed from the connecting rods, they should also be taken to a machine shop for checking for bend and twist, and connecting rods should be inspected for cracks and damage by temporarily removing rod caps and old bearing inserts, cleaning the surfaces, and checking for nicks or scratches before replacing the bearings and tightening the caps. If rebuilding due to a connecting rod knock, new rods should be installed.

Caution is advised when working on B1BC5 DOHC VTEC engines, as the manufacturer recommends using a connecting rod bolt stretch gauge to measure the stretch of the rod bolt during tightening, which is essential to avoid severe engine damage. Before installing piston/connecting rod assemblies, ensure the cylinder walls are clean, the top edges of each cylinder are chamfered, and the crankshaft is in place. Remove the cap from the number one connecting rod, clean the bearing surfaces, and avoid touching new bearing inserts with fingers. Clean the back side of the new upper bearing insert and install it in the connecting rod, ensuring the tab fits into the recess without using lubricant. Repeat this for the lower bearing insert in the rod cap. Position piston ring gaps correctly, lubricate the piston and rings, and use a piston ring compressor to guide the piston into the cylinder. Rotate the crankshaft to BDC and apply engine oil to the cylinder walls before gently inserting the piston/connecting rod assembly. Tap the ring compressor to ensure contact with the block and gently drive the piston into the cylinder while guiding the connecting rod into place. After installation, check the connecting rod bearing oil clearance using Plastigage, ensuring the bearing faces are clean and applying assembly lube before reinstalling the rod cap and tightening the nuts to the specified torque. Repeat the process for remaining pistons/connecting rods, keeping all components clean and ensuring the correct orientation of the piston. After all assemblies are installed, rotate the crankshaft to check for binding and measure the connecting rod endplay, ensuring it meets specifications to avoid the need for resizing at a machine shop.