The piston ring is the most serious wear of piston assembly of parts, wearing partsis one of the diesel engine. Cairo solar term door body called the worn piston ringsis the main external round surface wear and ring, the lower plane piston ring wear,sometimes may also occur in cementing, the fracture phenomenon.

Piston ring quality detection

1 piston rings worn to replace

Piston ring wear generally do not repair, but by changing the way to restore it, and the cylinder sleeve and piston ring groove with requirements. Replace piston ring,in order to ensure the good cooperation between the piston ring and ring groove,cylinder liner, piston ring must be selected and cylinder liner, piston ring groove at the same level of repairing size, and carries on the inspection and repair.

Elastic check 2 piston ring

Cairo said the solar term door body piston ring is to replace can be determined byelastic check piston ring. In order to ensure that the external surface of the piston ring and cylinder liner wall tightly, piston ring should have certain elasticity. If the elasticity is too small, then affixed to the wall of the cylinder is not tight enough, willcause leakage, poor heat; if the elastic force is too large, will accelerate the wear of cylinder wall and piston ring. The elasticity of piston ring of the test conditions can be tested in elasticity tester. No stretch test instrument, can check according to the following method:

(1) force the ring opening is closed (or open free to expand into a times the original free open) after the relaxation, the plastic deformation should not be greater thanthe original free opening 10%, illustrate the piston ring elastic qualified.

(2) the old ring free gap in comparison, if the old ring free gap is small, then theplastic deformation, elasticity decline. Can also be the old ring and the new ring istest on the lower side stand together, exerts a force on the ring by hand, if the opening against the old and the new ring, ring opening is still a considerable gap,said the old ring tension is not enough, should be replaced.

The piston ring assembly after the detection

1 to prevent the piston ring go to mouth way

General requirements for opening the engine piston ring should avoid the piston pin axis, and staggered 90b~ 120b, in order to reduce the leakage. The ringopening of the overlap in the same direction, called the piston ring go counterpart.Go to mouth of piston ring, the sudden appearance of the crankcase ventilationexhaust gas export steaming is not normal engine, and burning exhaust oil, power down, weakness, difficulty in starting fault compression. In general, the old change new old cylinder piston piston ring is more prone to go after the counterpart. This is because: the new piston ring piston and cylinder sleeve in the old old, because itsshape does not match, the engine is running after a period of time, Cairo said the throttle body under the high temperature, the new piston ring especially rapid wearof the top ring and the old cylinder jacket, with the result that the opening part of the elastic = decreased rapidly impaired ability to maintain the original position, theopening position easily rotate. In order to avoid living ring go counterparts, in thecomplete replacement of piston ring, if wear old cylinder jacket and piston and the amount of old cylindricity exceeds the limit, should also be replaced old cylinder jacket and piston cylinder liner wear old; if the old and old piston weight andcylindricity does not exceed the limit, according to the wear characteristics ofcylinder liner, suggestions the first and two piston ring opening adjustment in theold cylinder jacket of elliptical long axis (i.e., perpendicular to the pin holes near thecenter line), third, four ring opening adjustment in the vicinity of the short axis of the ellipse.

Measuring 2 opening gap

Piston ring in the cylinder, the opening should have a certain gap, to prevent thepiston ring after the expansion of the heated stuck in the cylinder. Opening the gap is too large, the sealing ring is poor, resulting in oil leakage, power down. Cairosaid the opening of the throttle body heat expansion gap is too small, will cause thegap disappears, ring at the top together, serious when can cause the occurrenceof scuffing of cylinder bore and piston ring, overheating, broken and deadlockingphenomenon. Therefore, in the diesel engine maintenance, must check the piston ring gap in cylinder.

When the examination, put clean into the cylinder liner wear of piston ring is not atthe top of the piston, used to push it flat, and then measured using a feeler gauge.Piston ring gap, are specified in the specification of diesel engine. On opening the gap is greater than the specified value should be replaced, is less than the specified value available benchwork file repair.