Genuine Volvo V40 Piston Ring

Volvo V40 Piston Ring Parts and Q&A

• Piston Rings
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  Q: What steps should be followed to check and fit piston rings correctly on Volvo V40?

  A:

  At this stage it is assumed that the pistons have been correctly assembled to their respective connecting rods and that the piston ring to groove clearances checked. Before the rings are fitted to the pistons, it is necessary for the end gaps to be checked with the rings fitted in the cylinder bores. Lay out the piston assemblies and the new ring sets in a way that will allow the components to be kept together during and after end gap checking. Position the cylinder block on the work surface, in a side downwards position, with access to the top and bottom of the bores. Take the No 1 piston top ring and insert it in the top of the first cylinder, pushing it down the bore using the top of the piston to ensure that the ring is still square with the cylinder walls. Position the ring close to the bottom of the cylinder bore as well as the lower limit of the ring travel, keeping in mind that the top ring and the second compression ring are different, the second compression being recognizable by the step on the lower surface of the cylinder. Measure the ring gap with the help of feeler blades, repeat the process with the ring set at the end of its travel and compare the measurements with specifications. If new rings are being fitted, then it is unlikely that the end gaps will be too small or if a measurement is found to be undersize then this must be corrected in order to avoid the end gaps of the rings contacting each other during the operation of the engine, which can lead to damage to the engine. Ideally, the end gap should be fitted with new piston rings of the correct fit but, if need be, the end gaps can be increased by careful filing of the ends of the rings. It is also unlikely that the end gap will be too large, if the gaps are too large check that the correct rings for the engine and cylinder bore size are being used. Repeat the checking procedure for all rings in the first cylinder and then for the rings in the other cylinders, taking care to keep rings, pistons and cylinders matched up. Once the ring end gaps have been checked and corrected if necessary, the rings can be fitted to the pistons using the same technique as used for removal but starting with the bottom scraper ring and working up. On non-GDI engines look at the text markings on one side of the top and bottom rings, these must face upwards when fitted; the middle ring is bevelled, and the bevel must face downwards when installed. For GDI engines, we must do the following: - First fit oil scraper in bottom groove consists of three parts: First fit spacer ring and above and below it upper and lower rings, as they are identical. Avoid expanding the compression rings too far and breaking them, and always go by any instructions that came with the new piston ring sets since different manufacturers may specify different procedures. Do not confuse the first and second compression rings, they have different cross-sections. When all the rings are in place, arrange the gaps of the rings 120 degrees apart for non-GDI engines or as specified for GDI engines.