ACL Main Bearings Honda B16A B18C K20 K24 – Race Series 5M1959H-STD

Description

ACL Main Bearings Honda B16A B18C K20 – Race Series 5M1959H-STD

Looking for ACL Main Bearings Honda B16A B18C K20 or K24? The ACL Race Series 5M1959H-STD set is a single part number that covers the DOHC B-series and the main K-series blocks. If you are rebuilding a VTEC bottom end or putting together a high-rpm K20 or K24 build, this is the standard-size crank main bearing set to start with. The set contains 10 half shells, enough for all five main journals.

The Race Series is ACL’s performance engine bearing range. You can identify a Race Series set by the “H” after the set number. “STD” means it suits a standard-size crankshaft journal.

Why choose ACL Race Series main bearings?

• Tri-metal construction: a high-tensile steel back, a copper-lead-tin lining, a nickel barrier and a lead-tin-copper overlay.
• Extended oil grooves: the upper shells are fully (180°) grooved and the lowers have a matching partial groove. This reduces interruption to the big end oil supply.
• Tapered groove run-out: this smooths the oil supply cut-off to the rod bearings and helps avoid pressure pulsing and cavitation.
• Increased crush: for better bearing retention and heat transfer into the block.
• Increased eccentricity: to cope with bore distortion at high rpm and help form the hydrodynamic oil film.
• No flash plating: this improves bearing-to-housing contact. The dark, tarnished colour of new Race Series shells is normal.
• Enlarged ID chamfers: to clear the larger fillet radii found on performance crankshafts.

ACL Main Bearings Honda B16A B18C K20 specifications (5M1959H-STD)

In the photos, note the dark, tarnished finish of the ACL Main Bearings Honda B16A B18C K20 shells. ACL says this colouring is normal for Race Series bearings and has no effect on how they work.

• Size: STD (standard crank). Half type: upper and lower.
• Journal (shaft) size: 54.98–55.00mm. Housing (tunnel) size: 59.00–59.02mm.
• Max wall at crown: 2.007mm. Max overall length: 20mm.

ACL’s guide works out main bearing clearance as 0.020–0.025mm per 25mm of journal diameter, plus 0.013mm. On this 55mm journal, that’s roughly 0.057–0.068mm. ACL also makes an HX version (5M1959HX-STD) that adds 0.025mm of clearance, plus 0.025mm and 0.25mm sizes. Contact us if you need one of those. Always measure the assembled clearance with a bore gauge and micrometer before final assembly.

Complete the bottom end

The matching rod bearings depend on the engine:

• B16A, B17A1, B18A1/B18B and B20B: ACL rod bearings for the Honda B16A.
• B18C: ACL rod bearings for the Honda B18C.
• K20A2, K20Z1, K24A and K24Z1: ACL rod bearings for the Honda K20 and K24.

Add the ACL 1T1957 thrust washers, or browse the full ACL Bearings range. Full application data is in the ACL Race Series catalogue.

Engines this main bearing set fits

• Honda B16A (1595cc)
• Honda B17A1, B18A1, B18B1, B18B2
• Honda B18C1, B18C2, B18C5, B18C7
• Honda B20B, B20Z
• Honda K20A2, K20A3, K20Z1
• Honda K24A, K24Z1

Not for SOHC B18A/B20A or DOHC B20A/B21A engines, or the K20C1. ACL lists different main sets for those.

Honda models this fits

The ACL Main Bearings Honda B16A B18C K20 set is linked to these models in our car filter:

• Honda Civic [EF/EF9] (1988-1992) – EF9 1.6i-VT / SiR (B16A)
• Honda Civic [EG/EG6] (1992-1995) – EG6 VTi (B16A2)
• Honda Civic [EK] (1996-2000) – EK4 VTi (B16A2)
• Honda CRX [ED] (1983-1993) – ED9 1.6i-VT (B16A)
• Honda Del Sol (1992-1998) – Del Sol VTi (B16A2)
• Honda Integra [DC2] (1994-2001) – Integra Type R (B18C)
• Honda Civic [EP/EP3] (2001-2005) – Civic Type R EP3 (K20A2) – not the 1.6 EP2
• Honda Integra [DC5] (2001-2006) – Integra Type R DC5 (K20A, Japanese import)
• Honda Accord [Cl7] (2004-2008) – Accord 2.4 (K24A) – not the 2.0