Vauxhall Workshop Service and Repair Manuals

Cylinder Bore Hole, Measure - Determine Piston-in-Cylinder Clearance  

  Measure   

Determine piston diameter with micrometer.   Offset piston 90 ° relative to piston pin axle and measure approx. 6 mm   from the lower edge.

  Assemble   

Assemble internal micrometer (50-100 mm) with corresponding probe tip and spacer, so that spread is slightly larger than measured piston diameter.   Insert pretensioned dial gauge (approx. 1 mm) into internal micrometer and tighten clamp bolt.

  Adjust   

Adjust internal micrometer to piston diameter.   For this, insert internal micrometer between both probe flats of external micrometer still adjusted to piston diameter (see illus. I).   Push guide sleeve over probe tip of internal micrometer and over probe flat of external micrometer.   Determine turning point of dial gauge needle (see illus. II) by careful balancing interior micrometer between probe flats of external micrometer. Set micrometer scale to zero at turning point of dial gauge needle.   Needle turning point corresponds to the actual piston diameter.

  Measure   

Cylinder Bore Hole, Measure - Determine Play   Measure cylinder bore hole on 3 levels (I, II, III), measure each crosswise. That is: 6 measurements are taken per cylinder bore hole.

  Measure   

Insert internal precision micrometer into cylinder bore at the given measurement point and determine the dial gauge pointer inflection point by carefully tipping back and forth (see illus. I). The difference between "scale zero" and the pointer inflection point is the determined running clearance (dimension 1, see illus. II). The largest dimension from the measurements 1 - 6 must be used as the basis for wear determination.   Example: measurement point 1 = 0.02 mm, measurement point 2 = 0.03 mm, measurement point 3 = 0.02 mm, measurement point 4 = 0.04 mm, measurement point 5 = 0.01 mm, measurement point 6 = 0.02 mm. The running clearance for this cylinder is 0.04 mm.   Determination of cylinder diameter       Piston diameter   78.95 mm   +   Play at one measuring point   + 0.04 mm   =   Cylinder diameter of this measuring level   = 78.99 mm     Determination of cylinder out-of-round       Highest dimension of a measuring level   78.98 mm   -   Lowest dimension of a measuring level   - 78.96 mm   =   Cylinder ellipticity of this measuring level   = 0.02 mm