The piston rings are manufactured with

1、If the back clearance of a piston ring

If the back clearance of a piston ring is excessive,（）Acompression pressure in the cylinder will be higherBcarbon will accumulate behind the ringCcombustion gases will penetrate beneath the ring landDpiston side thrust will be increased

2、With （）, the corrosion problems are mu

With （）, the corrosion problems are much reduced in a central cooling system.Ano equipment in contact with sea waterBless equipment in contact with fresh waterCmore equipment in contact with sea waterDless equipment in contact with sea water

3、The lowest ring of a piston is （）.

The lowest ring of a piston is （）.Aa coil springBa sealing ringCan oil distributor ringDmain seal ring

4、The pistons are cooled by oil supplied

The pistons are cooled by oil supplied from the forced （） system.Afresh waterBsea waterClubricationDfuel oil

5、The piston ring grooves for a standard

The piston ring grooves for a standard engine are （）Achromium-plate against wearBanti-corrosion treatedCwhite metal lined against wearDflame hardened against wear

6、Broken piston rings manifest themselve

Broken piston rings manifest themselves during the scavenge port inspection by（）ALack of elastic tension, when the rings are pressed into the groove by means of a stickBBlackish appearanceCFractured rings and missing ringsDall off the above