I rebuild engines. Here's what to do: Main bearing caps and rod bearing caps must be matchmarked and go back in exactly the same place with the same orientation they had. That is, the entire piston/rod assembly must go back in the same hole, the caps must meet the block or rod exactly as they did before. If you did not do this, the rods will have to be resized and or the block will have to be align bored/honed. The cylinders must be checked for excessive taper and at a minumum honed per the ring manufacturer's specifications. All bearings must be clearance checked with Plastigage. All clearances must meet the specifications in the service manual. Ring end gap must be within spec. Pistons must be installed with a ring compressor or you will likely break some rings. During reassembly, bearing shells must be properly placed. Bearings get oiled. Torque each main cap in a stepped sequence and then spin the crank by hand. Even in large engines, the crank will spin very freely. If there is any resistance, something is wrong. Same deal for installing the rods on the crank. Torque each one and spin the crank by hand. Each piston will add a little resistance but the crank will still spin very freely. If there is any real resistance, something is wrong. Both rod and main bearing bolts must have perfectly clean, undamaged threads and shoulders and be lightly oiled. Then squirt some oil around each piston and spin the crank by hand a few dozen times to make sure that no rings are broken and that they and the cylinders are very well oiled.
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