Trimetal connecting rod bearings Mitsubishi 4G63 4G63T

The Mitsubishi 4G63 and 4G63T four-cylinder engine

The 4G63 is the 2.0-litre (1,997 cc) four-cylinder of Mitsubishi's 4G6 family, with an 85 mm bore and an 88 mm stroke. It comes with a single overhead camshaft and 8 or 16 valves, with twin overhead camshafts and 16 valves, and as the turbocharged 4G63T used in the Lancer Evolution I to IX, the Galant VR-4 and the Eclipse Turbo; it also powered the Galant, Space Wagon, Space Runner, Outlander, L200, L300 and L400. This bearing set fits engines built from January 1992 onwards, 6-bolt as well as 7-bolt.

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

Three layers make up a trimetal bearing: the steel back for stiffness, the copper-lead intermediate layer for load capacity, then the anti-friction running layer that protects the crankpin. This set includes 8 half shells, that is 4 pairs.

Where an aluminium bi-metal bearing, designed for low to medium loads, withstands about 8,000 psi, a performance trimetal bearing goes up to 12,000 psi: 50% extra margin. That is what keeps it durable on an engine boosted by a turbo or supercharger, or pushed to high rpm.

Technical specifications

Technical guide

Designed for engine building and motorsport, these ACL and King trimetal connecting rod bearings carry much more load than an original bearing, whether the engine gains power, revs higher or receives a turbo or supercharger. They are available in several sizes: the standard size, a +0.025 / +0.026 mm size for a crankpin that has only been polished, +0.25 and +0.50 mm regrind sizes and the HX / STDX version with increased clearance for high-revving engines or engines needing a high oil flow. That makes it possible to put a reground crankshaft back into service without changing range and to set the clearance for the oil and use.

The two brands

	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. Its Calico version (HC suffix) adds the CT-1 coating, a dry film lubricant that reduces friction and abrasive wear.
	King Engine Bearings, an Israeli manufacturer active since the 1960s, produces high-performance engine bearings. Its pMax Black trimetal alloy is designed to withstand heavy loads, with the pMaxKote coating available as an option (XPC version).

Construction and advantages

Criterion	ACL Race Series	King Racing
Cross-section
Type	High-performance trimetal bearing	High-performance trimetal bearing
Country of manufacture	Australia	Israel
Construction	Trimetal: steel back, copper layer, soft surface	Trimetal: steel back, copper layer, soft surface
Alloy	Race Series (copper-lead)	pMax Black (hardened copper-lead)
Protective coating	No (Race); Calico CT-1 (HC)	pMaxKote (optional, XPC version): polymer coating on the surface that limits wear when lubrication drops (start-ups, thin oil film).
Available sizes	Standard to +0.50 mm (+ increased clearance HX)	Standard to +0.50 mm (+ increased clearance STDX)

Vehicle compatibility

This connecting rod bearing set fits the 4G63 and 4G63T four-cylinder engines, built from January 1992 onwards, of the following Mitsubishi models: