Genuine Volvo S40 Piston

Volvo S40 Piston Parts and Q&A

• Piston
  274399
  Q: How to remove and reassemble pistons and connecting rods on Volvo S40?

  A:

  On 1.8 and 2.0 litre petrol engines, the intermediate/main bearing section, the Crankshaft and the pistons cannot be removed and no separate parts are available and exchange units come with the crankshaft and the pistons and connecting rods already fitted. Begin by removing the Cylinder Head, oil pump and flywheel/driveplate and observe for a ridge of wear in the bores which may have to be removed prior to piston extraction. For 2.0 and 2.4 litre engines, make sure that there are identification marks on each connecting rod and cap when taking them off, and remove the connecting rod bolts and cap, bearing in mind that the connecting rod bolts and shell are new, to be used for reassembling. Insert the connecting rod and the piston again in to the bore and refit the cap correctly. Check for an arrow on the piston which indicates the proper orientation. For 1.6 litre engines, take pistons 1 and 4 to bottom dead centre, remove big-end bearing cap and take the bearing shell, taping them together if they are to be reused. Protect the crankshaft bearing journals by taping over the connecting rod stud threads, and then pushing the piston up through the bore, and removing it, securing the cap loosely to the keep order. Repeat for piston 4 and turn the crankshaft to reply NTD for pistons 2 and 3 and remove them similarly. Clean the piston/connecting rod assemblies and remove the original Piston Rings carefully, using feeler blades to stop them dropping into grooves. Scraping out carbon from the piston tops and ring grooves, being careful not to remove anything other than carbon. Needless to say, clean up the assemblies with solvent and inspect for damage; if there is no damage, original pistons can be refitted with new rings. Inspect each piston to ensure it has no cracks, scoring or burned areas and investigate any problems that are found to ensure they do not continue. Examine connecting rods for damage, and separate pistons and rods, if necessary, by removing circlips and pushing out gudgeon pins. If the pistons are worn, all of them must be replaced, and if the cylinder block was previously rebored, oversize pistons may be required. Measure ring to groove clearance and check gudgeon pin fit, if there is play, new bushings or oversized pins are required. Get Any new parts you need oil the gudgeon pin, re-fit the connecting rod and piston correctly secure gudgeon pin with circlip making sure the opening faces downwards for the other pistons.
• Piston
  274400
  Q: What steps should be taken before refitting the piston/connecting rod assemblies on Volvo S40?

  A:

  Before refitting the piston/connecting rod assemblies, make sure that the cylinder bores are clean and the Crankshaft and intermediate section are in place. Remove the big-end bearing cap from No 1 cylinder connecting rod, recording the marks made during the removal of the cap and cleaning out the bearing recesses using a lint free cloth. Keep everything spotless, and have new big end bearing cap retaining bolts ready. Clean the back of the new upper bearing shell and fit it to No 1 connecting rod, fit the other shell to the big end bearing cap and ensure that the shell with the black size marker goes to the connecting rod. For 'fractured' type rods and caps position the shells in the centre without a locating notch. Set the Piston Ring gaps in proper position, lubricate the piston and rings with clean engine oil and attach a piston ring compressor leaving the skirt protruding slightly. Turn on the crankshaft until No 1 big end journal is at BDC and pour the engine oil to the cylinder walls. For petrol engines, align the No 1 piston/connecting rod assembly in such a way that the arrow on the piston crown indicates the end of the timing belt, or that the channel is aligned with the piston cooling jet, and gently place the assembly in position in the No 1 cylinder bore. Tap the ring compressor to make sure that it is in contact with the block, and then tap the piston gently with a wooden hammer handle while sliding the connecting rod big-end onto the crankpin, and keep the ring compressor under the pressure to prevent the rings from popping out. If there is resistance, then stop and figure out the problem before continuing. Make sure the bearing surfaces are clean and put a layer of uniform clean engine oil on them and slide the connecting rod back onto the big-end journal and refit the bearing cap, lubricating the bolt threads and tightening in 2 stages to the specified torque. Repeat the process for the other assemblies, ensuring the back of the bearing shells and recesses are clean, the correct piston/rod assembly for each cylinder, the piston channel is aligned with the cooling jet and the cylinder bores and bearing surfaces are lubricated. After installation, turn the crankshaft by hand to see if there is any binding. If new components are fitted, measure the projection of the piston crowns above the cylinder head surface at TDC in order to find the correct head gasket. For diesel engines, anchor a DTI gauge to the cylinder block, zero on the head gasket mating surface, and measure the maximum projection at TDC for No 1 piston, do the same for the rest of the pistons and make a note of it. Use the maximum figure to choose the head gasket type needed.