Product description

With every engine rebuild, all bearings must be replaced. If the crankcase has been line-bored or the crankshaft has been ground, so-called undersize or oversize bearings are required.

The crankcase must be line-bored when the bearing saddle shows irregularities and/or when the bearing seats are no longer within the correct specification. The crankshaft is best checked by sliding your fingernail across the bearing surfaces. If you feel any irregularities, the crankshaft must be ground. Grinding is also necessary if the dimensions differ from the specification or if the crankshaft has runout.

For many undersize and oversize combinations, a matching bearing set is available. If excessive play has developed at the first main bearing (thrust bearing), the bearing saddle in the crankcase must be machined. Bearings are also available for this situation, where the thrust bearing is wider than standard. The term “standard” means nothing has been bored or ground. To be sure, always measure this with a micrometer or use a bearing measuring tool to determine the current dimensions precisely (see tab Aanverwanten).

Volkswagen produced bearings up to the mid-1960s where aluminium was the main component. Later this was changed to so-called “steel-backed” bearings. These bearings contain a steel reinforcement, making them less sensitive to wear and giving them a longer service life. For a stock engine this is usually not a problem, but for a tuned engine, where the bearings are subjected to much higher loads, we recommend steel-backed bearings. Volkswagen did not make this change without reason, and that is why a professional engine builder will also prefer steel-backed bearings for a stock engine, unless nothing else is available.

Important: If line-boring or grinding is required, always purchase the bearings first and only then have the crankcase line-bored or the crankshaft ground. This ensures the machining is carried out to the exact correct size, as this is a very precise operation. Each bearing set states the undersize or oversize difference.

Please note that bearings in opened packaging cannot be returned.