Operation CHARM: Car repair manuals for everyone.

Cylinder Block Assembly: Testing and Inspection






Pistons and Cylinder Bore, Checking

Pistons, Checking





- With an external micrometer 75 to 100 mm. Take measurement at approximately 15 mm from lower edge of piston skirt and offset 90° to piston axis.

Deviation from nominal size: Max. 0.04 mm.






Piston Ring Gap, Checking





- Push piston ring squarely from above down to approximately 15 mm from bottom end of cylinder. To do this use a piston without rings.






Piston Ring Groove Clearance, Checking





- Clean the ring groove of piston before checking.






Cylinder Bore, Checking





Special tools, testers and auxiliary items required

Inside Micrometer Set 18-100 mm (US1033/S)

Internal Dial Gauge (VAS 6078)

Engine and Transmission Holder (VAS 6095)


Do not bore, hone, grind or rework the cylinder bores with workshop tools. Reworking damages the surface of the cylinder bore.

- Using a (US1033/S) or (VAS 6078) measure in a diagonal sequence at 3 positions transversely - A - and longitudinally - B -.

Deviation from nominal size: max. 0.08 mm.






Measurement of cylinder bore may not be performed when the cylinder block is mounted in (VAS 6095) , false measurements are possible.