Tri-Metal Big End Bearings BMW M3 E36 3.0 24V S50B30

The tri-metal big end bearing sets ACL RACE and KING RACING for the S50B30 engine contain 12 bearing shells.

Below (click on the image) you will find the tri-metal main bearings for the BMW S50B30 engine and the plastigage strips used to check the bearing / crankshaft running clearance:

Technical specification

• Crankshaft big end journal diameter (min/max): 49.975 / 49.991mm
• Connecting rod bearing bore (min/max): 53.000 / 53.015mm
• Maximum thickness: 1.493mm
• Size(s): standard, standard with HX clearance, +0.025 or +0.25mm
• Anti-friction coating: none
• References: 6B1515, 6B1515H-STD, 6B1515HX-STD, 6B1515H-.025, 6B1515H-.25

ACL Race Series tri-metal bearings are made to tight tolerances. CNC machining works to the micron, followed by metrology checks on the diameter, thickness and width of the ACL Race Series tri-metal bearing. The ACL Race Series bearings therefore give a reliable and consistent fit in your performance engine. The ACL Race Series tri-metal bearings are in fact made up of 4 layers:

• SAE1010 steel on the outside
• 0.3mm copper alloy
• 0.0001mm nickel
• Copper alloy from 0.013 to 0.018mm

This choice of materials, combined with the manufacturing processes, makes the ACL Race Series tri-metal bearings more resistant to increases in power, torque and engine speed. The compressive strength of the ACL Race Series tri-metal bearings brings reliability to your engine even with heavily boosted turbo or supercharger builds, or highly strung engines running high revs.

Technical specification

• Crankshaft big end journal diameter (min/max): 49.97 / 49.99mm
• Connecting rod bearing bore (min/max): 53.00 / 53.02mm
• Maximum thickness: 1.491mm
• Size(s): standard, standard with HX clearance, +0.026 or +0.25mm
• Anti-friction coating: none
• References: CR6854, CR6854XP, CR6854XP STDX, CR6854XP.026, CR6854XP0.25

Since 1960 KING RACING has designed and manufactured high performance, high quality bearings. Beyond its very capable production machinery, King Racing uses simulation software to analyse the thermodynamics, dynamics and elasto-hydrodynamics of its bearings. KING RACING tri-metal bearings are produced in pMax Black, a tri-metal alloy 24% stronger than any existing tri-metal bearing.

KING RACING bearings are made up of 3 to 4 layers (depending on the application):

Outside: steel Intermediate: lead bronze Inside: babbitt with a high copper content Anti-friction coating containing lubricant and ceramic additives