ACL main bearings BMW M20 1977–1988 STD

ACL Race main bearings for BMW M20B20, M20B23, M20B25 and M20B27 engines with standard crankshaft. This set fits early BMW M20 engines up to 03/1988. ACL Race Series is developed for tuning, performance and motorsport, where the main bearings are exposed to higher loads, higher RPM and greater demands on load capacity and reliability than standard bearings.

ACL Race Series main bearings are made from high-strength F780 trimetal material with hardened steel backing, copper/lead alloy and a durable overlay coating. The material choice, heat transfer and oil distribution are developed to ensure a stable oil film and high load capacity at high RPM and demanding operating conditions.

7M1539H-STD is the STD version, which means the bearings fit a standard crankshaft with standard bearing dimensions. The set is a full groove main bearing set with identical bearing halves and thrust bearing in position 6.

Note:
For BMW M20 engines from 04/1988 onwards, 7M1532H-STD must be used instead.

Specifications:
Type: ACL Race main bearings H-STD
Material: Trimetal copper/lead alloy (F780) with steel backing and overlay
Crankshaft: Standard size (STD)
Bearing design: Full groove main bearing set with identical bearing halves
Axial/thrust: Position 6
Contents: 14 bearing halves (7 complete main bearings)
ACL part number: 7M1539H-STD

Maximum overall length: 20.00 millimetres
Maximum overall length thrust bearing: 24.94 millimetres
Maximum shaft size: 59.990 millimetres
Maximum tunnel size: 65.019 millimetres
Maximum wall at crown: 2.488 millimetres
Minimum shaft size: 59.971 millimetres
Minimum tunnel size: 65.000 millimetres

Fits engine code:
M20B20 / M20B23 / M20B25 / M20B27