ACL trimetal connecting rod bearings Opel Saab Z22SE Z20NET B207

The GM Ecotec Z22SE, Z20NET and B207 four-cylinder engines

The Z22SE is General Motors' 2.2-litre Ecotec inline four with double overhead camshafts and 16 valves, fitted by Opel and Vauxhall; the Z20NET is its 2-litre turbocharged version and the B207 engines power the Saab 9-3. ACL lists the same bearing set for these engines: a single set covers the family.

From the factory, this engine is fitted with standard production connecting rod bearings, sized for the loads of the original engine: as soon as power, engine speed or boost pressure increase, they reach their limits.

Trimetal connecting rod bearings

A trimetal bearing stacks three layers: a steel back, a copper-lead intermediate layer with high load capacity and an anti-friction running surface that protects the journal. The complete set contains 8 half shells, four pairs for a four-cylinder engine.

The original bearing relies on an aluminium alloy over a steel back, intended for low to medium loads, whereas trimetal is designed for high, sustained loads: an aluminium bi-metal takes around 8,000 psi, a performance trimetal up to 12,000 psi, 50% more. Hence better resistance and better durability on turbocharged, supercharged and high-revving engines.

Technical specifications

Technical guide

The ACL rod bearings shown here are trimetal bearings, designed for engine building and racing. Compared with an original bearing, they handle far higher loads: they cope with increased power, high rpm or the addition of a turbo or supercharger, where a standard bearing quickly reaches its limit.

The brand

ACL Bearing Company, an Australian manufacturer of high-performance engine bearings since 1949, offers with its Race Series precise trimetal bearings, available in many sizes and proven on built engines worldwide.

Vehicle compatibility

This connecting rod bearing set fits the Z22SE, Z20NET and B207 four-cylinder engines of the following Opel and Saab models: