Long forged connecting rods Mitsubishi 2.0 16v 4G63 7-bolt 22 mm pin 162 mm centres for forged pistons

The Mitsubishi 4G63 engine (7-bolt)

Mitsubishi’s 4G63 is an inline four-cylinder of 1,997 cc (85 mm bore, 88 mm stroke) with double overhead camshafts and sixteen valves. In turbocharged 4G63T form it built the reputation of the Lancer Evolution and the second-generation Eclipse. From around 1993, Mitsubishi adopted a crankshaft held by seven bolts, the “7-bolt” architecture that equips the entire Lancer Evolution IV to IX line.

Capped at 280 hp on Japanese Lancer Evolution models, the “7-bolt” 4G63T holds a huge tuning margin: a larger turbo and matched engine management routinely take it from 450 to 700 hp in race use. The rods in this listing feature a long 162 mm centre-to-centre length, reserved for stroked blocks: by raising the rod-to-stroke ratio it reduces rod angularity and eases piston thrust against the cylinder wall.

From 350 to 400 hp, the stock rod reaches its limit: it distorts, stretches and finally breaks under compression and inertia shocks. Switching to forged rods is the first reliability step of a performance-oriented “7-bolt” 4G63T.

Forged connecting rods

A link between piston and crankshaft, the connecting rod converts translation into rotation. Driven by boost and the high rpm of a tuned Evolution, it takes considerable loads. Its long 162 mm version targets engines with revised stroke, whose kinematics call for an increased centre distance.

Forged from through-hardened alloy steel, these rods clearly outperform a cast or sintered factory part in fatigue strength and stiffness. Hot press-forming orients the metal grain flow along the stress lines, reinforcing the part where it is most loaded.

Depending on profile and hardware, they suit a hard-driven street build as well as a rally or circuit block, across the whole range of a “7-bolt” 4G63T.

Technical specifications of the 4G63 forged rods (7-bolt, 22 mm pin)

Tightening torque and stretch

On reassembly, apply the hardware reference and the stretch-tightening method given above. Measuring bolt stretch, safer than torque alone, ensures even, repeatable cap preload.

Technical guide

Forged 4340 steel: what is it?

The 4340 is a low-alloy steel combining nickel, chromium and molybdenum. Its balance of strength, toughness and fatigue endurance makes it the material of choice for high-performance rods, in aerospace and motorsport alike.

Forging followed by quenching and tempering brings its tensile strength to around 1,200 to 1,300 MPa without sacrificing ductility. The rod then absorbs millions of alternating tension and compression cycles without crack initiation, where a factory part would eventually give way.

Connecting rod profiles

The rod-body geometry sets its stiffness, weight and strength. This reference is offered in the I-HD profile, described below.

I-HD profile (I-Beam Heavy Duty, Manley Pro Series Turbo Tuff range): a thickened, reinforced I-section built to handle the high boost pressures and heavy torque of the most built Evolution 4G63T engines. It is the ideal profile for a long rod in a stroker configuration.

How to choose your rod bolts?

The most loaded fastener in the assembly, the rod bolt retains the cap every cycle under major stress. This reference is fitted with ARP hardware, presented below.

ARP 2000: the versatile reference. Its tensile strength is around 220,000 psi (about 1,517 MPa) and allows close to 200 hp per cylinder in 3/8" diameter, covering the vast majority of 4G63T turbo builds; it tolerates engine speeds up to 8,500 rpm. Reliable, robust and with no shelf-life limit, it is the starting choice for performance builds.

Measuring bolt stretch

Discover the ARP stretch gauge

The brands offered

Manley Performance: an American manufacturer recognised worldwide for its forged racing rods. The H-Beam and Pro Series I-Beam Turbo Tuff ranges equip the highest-performing DSM builds and are renowned for their manufacturing consistency and reliability under heavy load.

Glossary

1) Small end 2) Small-end diameter 3) Rod beam 4) Rod bolt 5) Big end 6) Rod nut / bolt 7) Rod cap 8) Big-end diameter 9) Center-to-center

Vehicle compatibility for the Mitsubishi 4G63 engine (7-bolt)

These long forged connecting rods are designed for the “7-bolt” 4G63T four-cylinder fitted to the following models:

OEM reference: (set of 4 connecting rods).

Why it is the most cost-effective solution?

Compared with the protection it gives, a set of forged rods is a measured outlay. On an Evolution 4G63T, a stock rod failure usually takes out the block, the crankshaft and sometimes the cylinder head.

Fitting forged rods from the engine’s design stage avoids a repair whose cost far exceeds that of the set. On a heavily built block, it is the most cost-effective insurance.