Genuine Mercedes-Benz 190E Piston Ring

Mercedes-Benz 190E Piston Ring Parts and Q&A

• Piston Ring Set
  002-030-20-24
  Q: How should the end gaps of new piston rings be checked and fitted before engine reassembly on Mercedes-Benz 190E?

  A:

  During the end gap measurement and subsequent reassembly of the engine, the end gaps are measured before installation of new radiating Piston rings by positioning of the prior piston/connecting rod apparatuses characteristically against the corresponding new piston-shaped rings and extending through the center-gauge at the ring end break along with the center-gauge ring. Fit the top ring to the first funnel and press it down the bore with the top of the piston so that the ring will always stay within the square of the sides of the cylinder, coming as near to the bottom of the cylinder bore as the ring is allowed to move. The first and second compression rings are dissimilar and the second compression ring is distinguished by the step on the lower surface of the ring. Check the end gap with 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 readings with the specifications. When the gap is too narrow, it is necessary to make it as large as possible to avoid contacts of the ring ends of the two sections during engine operation, which may cause severe damage; new piston rings that will offer appropriate end gap should be installed. The end gap may be raised as a final measure by carefully scraping the ring ends with a fine file, and must be careful whilst doing so, as piston rings are sharp, and cut easily. When new piston rings are used, it is not very likely that the end gap will exceed the desired value, but in the event of permanently large gaps, be sure you are using the correct rings to fit the engine and cylinder bore size. Repeat the checking process with each ring in the first cylinder, and the rings in the other cylinders, pitting rings, pistons and cylinders together. When the gaps at the ends of rings are checked and repaired, as needed, the rings may be removed and returned to the pistons, in the same manner, beginning at the lowest (oil control) ring, then upward. Installation Fit the oil control ring, first insert wire expander, then install the ring with its gap facing 1806 degrees relative to the protruding ends of the wire expander, be sure that the rings are sufficiently installed similar side up, with the top of the rings often identified by the mark indexed TOP. Position the gaps of the upper ring and the second compression ring 120 degrees to each side of the oil control ring gap, such that no ring gaps appear to rise above the gudgeon pin hole. Each set of new piston rings should have instructions, which must be adhered to, as different manufacturers have various sets of rules, and the bottom and second compression rings must not be confused, as they have different cross-sections.