Genuine Mercedes-Benz 190E Piston

Mercedes-Benz 190E Piston Parts and Q&A

• Piston
  102-030-97-37-54
  Q: How to clean and inspect piston/connecting rod assemblies on Mercedes-Benz 190E?

  A:

  Clean up the piston and connecting rod assemblies before commencing to carry out the inspection procedure by scraping the two parts of the pistons with the original Piston Ring. Fit the old rings to the old feeler blades over the pistons, taking care never to scratch the pistons, and to ensure the rings do not fall down the empty grooves. The outer ring contains an expander, each pair of rings should be used with the associated piston again with that orientation in mind. After most of the deposits come off, use a hand-held wire brush or fine emery cloth to scrape away carbon on the top of the piston. Clean the carbon out of the ring grooves with an old ring, adding at the same time, without injuring the grooves, half the ring. Clean the piston and connecting rod assembly with paraffin or an appropriate solvent after cleaning so that the oil return holes remain clear. Check the pistons and the cylinder bores, as you would any thing else, to see whether they are cut or worn more than they should be; and, finding them sound, go and care by the way of the bore, to make sure that the piston diameters are not too great, in relation to the bore diameters. Overly large piston-to-bore clearance can necessitate reboring of the block and new pistons and rings being installed. Check evidence of wear, cracks, notching or scuffing on the pistons, holes or burned areas on the crown, which could determine overheating or excessive combustion. Pitting type of corrosion implies leaking of the coolant, to the combustion chamber or crankcase, which requires a remedial measure. Mercedes-Benz dealer can get new pistons. check the connecting rods: they should not be bent or deformed; and the gudgeon pins, fixed by circlips. Take off the circlips with a small flat-bladed screwdriver and lever the gudgeon pin out and install new circlips; then replace the old circlips with new ones during reassembly. Check gudgeon pin and connecting rod small-end bearing on wear, so that the pin fits freely through the bush, without apparent movement. When connecting rods are not straight, seek the assistance of an engine overhaul specialist. Acquire any new components in centre, Mercedes-Benz dealer, where new pistons are supplied with gudgeon pins and circlips. Install the piston in regard to the connecting rod depending on the type of engine, in order to bring the small bore of oil oil offset to the end of timing chain. TIP Stand the gudgeon pin in clean engine oil, then press the pin through the piston by fitting it to the small-end of the connecting rod; the piston pivotes freely, so before fitting the pin, two new circlips are placed on the pin, and fixed in their grooves.