Before dismantling of the piston and connecting rod assemblies, the cylinder heads and oil pan have to be disconnected. There should also be checked any ridges at the highest point of ring travel with fingernail; these ridges should be eliminated by the use of a ridge reamer because the failure to do so may cause breaking of the piston. Upon removing the said ridges, position the engine in a way that the
Crankshaft will be upwards then, take off the main bearing cap support brace. Examine the piston pin bore hole clearance by using feeler gauges, and compared the same with required specifications; if it exceeds it then new connecting rod may be required. Locate the connecting rods and the caps distinctly and thereafter, loosen evenly, the connecting rod cap bolts or nuts with the old bolts being used to measure clearance while the new bolts can be used to finally tighten the cap bolts.. To do this, carefully unbolt the screw for the connecting rod cap and bearing insert, followed by letting the connecting rod/Piston assembly to be extracted from the top Lateral opening of the engine. After the removal of the connecting rod assembly, replace the caps and bearing inserts that you have removed to the corresponding rods; it is advisable to retain the original inserts so that they will not suffer from mishandling. The pistons and connecting rods are now ready to have a look at and refurbish if necessary. Before fitting, new piston rings should be inspected with a view to measuring the ring end gaps as well as ensuring that the piston ring side clearance it right. The piston/connecting rod assemblies, and new rings are laid out in sets based on the intended installation. Place the top ring in the first cylinder so that it is in line with the cylinder wall, check the end-gap using feeler gauges. If the gap is too small then with extra caution use a file to increase the size of the ring ends. Do this for every ring and make sure of the right setting whereby the oil control ring comes first followed by the middle and the last one ought to have the right markings facing the correct direction. Cylinder Walls, The edges of it should be chamfered and with crank shaft in position before Piston/Connecting Rod Assemblies are fitted. Remove the old bearing inserts from the connecting rod small end and cap and do not apply lubricant to the new bearing insert before pressing them into place making sure that they fit properly. The gaps of the piston ring should lie around the piston, the piston and the ring need to be lubricated and the use of the piston ring compressor is made during this process. Place the piston/connecting rod assembly into the cylinder bore, ensuring that the 'weight designation' mark is aligned with the front of the engine and tap the piston gently into position while gently lowering the connecting rod onto the crankshaft journal. Place a Plastigage at the connecting rod bearing oil clearance, clean the surfaces if there is grease or assembly lube. Place the rod cap back in position and if its bolts where removed or nuts were loosened then replace them and tighten them to the recommended torque tightness. Perform the same process for other assemblies and please make sure that they are clean and faced the right way. Following installation, align the crankshaft and turn it over to fit and to check for any binding especially under the connecting rod journal and also check on the connecting rod end play and rectify it if necessary. Last, the main bearing cap support brace and bolt down tight to the adequate torque of the bolt is placed.