Checking the inner diameter of the cylinders (VW Beetle)

The clearance between the piston and the cylinder is determined by separately measuring the diameter of the piston and the cylinder. It cannot be measured with a feeler gauge.

To measure the cylinder diameter, a bore gauge is required, which is first set to the nominal size (see table below).



The bore gauge is inserted approximately 1015 mm below the inner edge of the cylinder.

If, when measuring the diameter of the piston and cylinder, it is determined that the working clearance is close to 0.2 mm, then the piston together with the cylinder must be replaced as a set with a new one from the same size class. The difference in piston weights should not exceed 10 g. A piston whose cylinder shows signs of wear cannot be replaced separately. But if, on the contrary, the piston is damaged, and there are no signs of wear on the cylinder, then it is sufficient to install a new piston of the appropriate size class for the given cylinder.

Attention! Only cylinders and pistons of the same size class must be installed in the engine. When deciding whether to install new pistons and cylinders, the determining factor, along with the presence of signs of wear, is oil consumption. If it exceeds 1 liter per 1000 km, then engine repair is necessary. The distribution of cylinder-piston pairs into three size classes is carried out according to the following scheme:

Engine	Size class of pistons	Color of labels	Cylinder diameter, mm	Piston diameter, mm
1200, 1300	Nominal	Blue	76,992-77,008	76,95
	Nominal 77.0 mm	Pink	77,002-77,018	76,96
	1st repair	Blue	77,492-77,508	77,45
	Nominal 77.5 mm	Pink	77,502-77,518	77,46
	2nd repair	Blue	77,992-78,008	77,95
	Nominal 78.0 mm	Pink	78,002-78,018	77,96
1600	Nominal	Blue	85,492-85,508	85,45
	Nominal 85.5 mm	Pink	85,502-85,518	85,46
	1st repair	Blue	85,992-86,008	85,95
	Nominal 86.0 mm	Pink	86,002-86,018	85,96
	2nd repair	Blue	84,492-86,508	86,45
	Nominal 86.5 mm	Pink	86,502-86,518	86,46

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