Acura 10002-PH7-660 Engine Assembly, Block (C25A1-010)

Using a gasket scraper, remove all traces of gasket material from the engine block, taking care not to nick or gouge the gasket sealing surfaces. Remove the main bearing caps and bridge, separating the bearing inserts from the caps and the engine block, tagging the bearings to indicate their original cylinders, with the oil groove identifying the upper bearings. Remove all threaded oil gallery plugs from the block, which may be very tight and could require drilling out and retapping the holes, using new plugs upon reassembly. If the block is extremely dirty, it should be taken to an automotive machine shop for steam cleaning or tanking. After cleaning, ensure all oil holes and galleries are cleaned again using brushes designed for this purpose, flushing with warm water until clear, drying thoroughly, and wiping machined surfaces with light rust preventive oil, utilizing compressed air if available to expedite drying and clear oil holes and galleries. If the block is not excessively dirty, a thorough cleaning with hot soapy water and a stiff brush is sufficient, ensuring all oil holes and galleries are cleaned, dried completely, and coated with light oil. Clean the threaded holes in the block to ensure accurate torque readings during reassembly by running the proper size tap into each hole to remove rust, corrosion, thread sealant, or sludge, restoring damaged threads, and clearing debris with compressed air if possible. Clean the threads on the head bolts and main bearing cap bolts as well. Reinstall the main bearing caps and tighten the bolts finger tight. Apply non-hardening sealant to the new oil gallery plugs and thread them securely into the holes in the block. If the engine will not be reassembled immediately, cover it with a large plastic trash bag to keep it clean.

The block should be cleaned first, before inspection. Check visually for cracks, rust and corrosion and strips threads in threaded holes. You should have the block looked for hidden cracks by an automotive machine shop qualified for that work. Block if possible and if defects are found, then repair or replace. Have the cylinder bores measure for scuffing and scoring, i.e., check the diameter at the top, center and bottom and parallel to the crankshaft axis. As time goes on, you will learn how to accurately measure so work slowly and repeat checks until the accuracy is satisfactory with you. In case, the measuring precision tools are unavailable, feeler gauge stock is available at auto stores, it can be used to get piston to cylinder clearances. Check clearance with a feeler gauge between the piston and cylinder on the thrust face and insert a feeler gauge to the matching piston position, checking it is between the piston and cylinder, not piston stuck down inside the cylinder. If the piston falls through the cylinder with little pressure there is excessive clearance and a new piston is required. The cylinder is tapered, if the piston binds at the lower end with loose spot, if any tight spot encountered while rotating the piston/feeler gauge." Repeat for the other pistons and cylinders. Oversize pistons and rings are needed if the cylinder walls are badly scuffed, scored, out of round or tapered so far that the engine block must be rebored and honed by an automotive machine shop. On the block deck check for distortion with a precision straightedge and feeler gauge; if worse than specified, distortion can be resurfaced in an automotive machine shop. Obviously, if to rebore is unnecessary and if the cylinders are in reasonable order, albeit worn to some extent, and if the necessary piston to cylinder clearance can be maintained, honing will suffice.

For specific models, remove components such as the alternator, distributor, and spark plug wires.

Factors include mileage, frequency of servicing, regular oil and filter changes, and overall maintenance. High mileage does not always indicate a need for an overhaul, nor does low mileage guarantee that one is unnecessary.