Genuine Volvo S70 Piston Ring

Volvo S70 Piston Ring Parts and Q&A

• Piston Rings
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  Q: How should the piston rings be checked and fitted to ensure proper assembly on Volvo S70?

  A:

  At this point, it is assumed that the pistons have been correctly assembled to their respective connecting rods, and the piston ring-to-groove clearances checked. Before fitting the rings to the pistons the end gaps need to be checked with the rings fitted into the cylinder bores. Lay out the piston assemblies and the new ring sets to ensure that the components are kept in their groups during and after end gap checking. Place the cylinder block on the work surface, on its side, so that it may be accessed at the top and bottom of the bores. Take the No 1 piston top ring and place it on the top of the first cylinder urging it down the bore with the top of the piston to insure that the ring is square with the cylinder walls, in a position in the cylinder bore near the bottom and on the limit of ring travel. Note that the top and second compression rings are different, the second ring being identified by the step in its lower surface. Measure the gap of the ring by using feeler blades and repeat the process with the ring at the top of the cylinder bore at the upper limit of its travel and compare the measurements with the figures given in the Specifications. If new rings are being fitted, the end gaps are not likely to be too small; however, if it is found that a measurement is undersize, this would need to be corrected to avoid the chance of the end of the rings coming into contact with each other during the operation of the engine that could result in damage to the engine. Ideally, new piston rings with the correct end gap should be fitted but, as a last resort, the end gaps can be increased by carefully filing the ends of the rings with a fine file. Mount the ring in a vice that has soft jaws and slip the ring over the face of the file with the ends contacting the file face, slowly move the ring to remove material from the ends, taking care as piston rings are sharp and easily broken. It is equally 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 each ring in the first cylinder and then repeat for the rings in the remaining 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 for removing them, starting from the bottom scraper ring and working your way up. Observe the text markings on one side of the top and bottom rings which must face upwards when fitted, while the middle ring is bevelled and must face downwards when installed. Don't expand the compression rings too much, or they will break, and always refer to any directions provided with the new piston ring sets as different manufacturers may have different instructions. Do not confuse the top and second compression rings as their cross-section differs and when all the rings are set, arrange the ring gaps 120 degrees apart.