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Inspection Methods of Piston Ring for Diesel Generator Set

Oct. 26, 2020

Today Starlight Power factory tell you how to inspect piston ring of diesel generator, hope this article is helpful to you.


In order to ensure that the diesel generator piston ring, piston ring groove and cylinder wall of a good fit, large piston ring files should not be used as small for engine repair. The piston ring with the same repair level as the cylinder and piston should be selected according to the repair size of the cylinder. At the same time, the opening clearance, side clearance, back clearance, elasticity and light leakage of the selected piston ring should be checked.


1. Maintenance method of opening clearance

Diesel generator piston ring opening clearance refers to the clearance between the two ends of the ring opening after the piston ring is installed in the cylinder, so it is also called end gap. It is used to prevent the piston ring from being stuck in the cylinder due to thermal expansion. When checking the piston ring opening clearance, install the selected piston ring into the cylinder, push the piston ring to the non worn part of the cylinder with the piston head, and then measure the opening clearance with a feeler gauge. When the clearance is greater than the specified value, another piston ring should be selected; if the clearance is less than the specified value, a manual grinding tool or a fine flat file can be used to file the ring end. When filing, pay attention to the smoothness of the ring. After filing, remove the burr on the outer ring to prevent the edge of the ring mouth from damaging the cylinder wall.

Starlight generator set

2. Maintenance method of side clearance

The side clearance of diesel generator piston ring is the clearance between ring and ring groove plane. When measuring, put the piston ring in its own ring groove. It is required that the piston ring can rotate flexibly without astringency. The clearance at one side of the piston ring can be measured with a feeler gauge. When testing the side clearance of ladder ring, it should be installed into the cylinder together with the piston for measurement, and the value should meet the requirements. If the side clearance is too large, it will affect the sealing effect of the gas ring, so it should be re matched. If the side clearance is too small or the ring width is larger than the ring groove, the ring of other shapes can be placed on the o with platform or flat glass, except for the trapezoidal ring which should be re selected and ground_ Grind on No. 1 gauze. When grinding, make the ring close to the abrasive cloth and move evenly. Can also be coated with flat glass to grind sand, drip oil for grinding.


3. Maintenance method of back clearance

The back clearance of diesel generator piston ring refers to the clearance between the back of piston ring and the bottom surface of ring groove after the piston and piston ring are installed in the cylinder. In order to measure conveniently, the distance between the piston ring falling into the ring groove and the shore side is usually taken as the measured value. It is generally considered that the measured value should be greater than 0 ~ 0.35mm, and if it is too small, the ring will be stuck in the cylinder. If the back clearance is too small, it can be solved by turning the piston ring groove.

4. Check of piston ring elasticity

To check the elastic force of the piston ring, put the piston on the elastic tester, pull the operating handle, fix the handle when the piston ring is compressed to the specified value of the opening clearance, and then adjust the scale to balance the two ends. The corresponding scale of the pound code is the elastic value of the ring. In general, this measurement is rarely carried out. The repair personnel feel the elasticity with their hands, that is, they can feel "hard" when they pinch the outer circle.

5. Inspection of light leakage

The degree of light leakage refers to the degree that light can penetrate between the ring and the cylinder wall when the piston ring is installed in the cylinder. During the inspection, put the piston ring horizontally in the cylinder, cover the inner circle of the ring with a circular plate, place the light source under the cylinder, and then check the light leakage gap. It is required that there should be no light leakage within the range of 30 ° at both ends of the piston ring opening gap. The light leakage of the same piston ring should not be more than two places, the total radian should not exceed 45 ° and the light leakage gap should be less than 0.03mm. When the light leakage gap is less than 0.015mm, its radian can be appropriately relaxed, but it should not exceed 120 °.


We produce electric generator with engine Cummins, Perkins, Volvo, Deutz, Shangchai, Yuchai, Weichai, Wuxi, Doosan, Ricardo, MTU etc. Power generator is from 25kva to 3125kva, covering open type, soundproof type, canopy type, ISO container type, mobile trailer type, mobile type. Welcome to contact us by email sales@dieselgeneratortech.com. 

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