4G63 and 4B11 rebuild kits: Evo engine packages explained

The 4G63 is the engine that made Mitsubishi fast, and it is still one of the most rebuilt engines in New Zealand. Most of them come apart for one of three reasons: a piston that lost an argument with detonation, a rod bearing that ran out of oil, or a head gasket that lifted when the boost went up. There is also crank walk, which is its own conversation and is covered below.

What follows is what a real 4G63 rebuild kit contains, how our packages differ across the VR4, Evo 1 to 3, Evo 4 and Evo 5 to 9, and where the 4B11 in the Evo X fits. Before you scroll: we sell the parts and the packages. We do not sell complete or crate engines.

The short answer

• A refresh kit is bearings, gaskets, seals and plugs with the standard rotating assembly left alone. Fine for a stock power car that needs sealing up.
• A forged package is CP pistons, Manley or Eagle rods, an ARP or Mazworx head stud kit, a main stud kit, ACL Race Series bearings and a metal head gasket. That is what our 4G63 packages are.
• Compression is a real choice on this engine, not a detail. We list packages at 8.5:1 and at 9.0:1, and the right one depends on your turbo and your fuel.
• Buy against your generation. VR4, Evo 1 to 3, Evo 4 and Evo 5 to 9 do not share every part, and ordering the wrong bearing set is a week lost.

What is in a rebuild package

The standard contents are listed on our Engine Rebuild Packages page: forged pistons, forged rods, a Cometic MLS or Tomei head gasket, an ARP or Mazworx head stud kit, an ARP or Mazworx main stud kit where the engine takes one, and ACL Race Series main and rod bearings. Package pricing sits below the total of the same parts bought individually.

The 4G63 engine packages then split by generation, and every title carries the spec.

For the VR4, the CP piston and Manley rod package at 8.5:1 is the boost focused option, with a 9.0:1 version of the same build and CP and Eagle rod packages at both compressions.

Evo 1 to 3 gets the CP piston and Eagle rod package at 8.5:1 or the same combination with Manley rods.

Evo 4 packages include the head gasket in the title. There is a CP piston, Manley rod and 1.2mm Tomei gasket build at 9.0:1 and a CP piston, Eagle rod and 1.3mm Cometic build at 8.5:1.

Evo 5 to 9 runs the widest choice: CP pistons, Manley rods and a 1.2mm Tomei gasket at 8.5:1, a 1.5mm Tomei version at 9.0:1, or CP pistons with Eagle rods and a 1.3mm Cometic at 8.5:1.

Choosing pistons, rods and compression

Every 4G63 package runs CP pistons. We also list CP Evo pistons on their own in the VR4 collection at 8.5:1, 9.0:1 and 10.0:1, in 0.5mm and 1mm oversize, which is useful when the block has already been bored and you only need the pistons.

Rods split the same way they do on every engine we sell. Manley rods go into the builds chasing rpm and drag numbers. Eagle rods are the value option and live happily in fast street Evos. Both are a long way past a standard 4G63 rod, and neither is usually what fails. Detonation and oil supply are what fail.

Compression is where 4G63 builds go right or wrong. The 8.5:1 packages give you knock margin for a bigger turbo, more boost and the fuel we actually get here. The 9.0:1 packages keep cylinder pressure and response for a smaller turbo or a car that spends its life on the road. Gasket thickness stacks on top of that, which is why the Evo 4 and Evo 5 to 9 packages name a 1.2mm, 1.3mm or 1.5mm gasket. Tell us the turbo and the fuel and we will point you at one rather than guessing.

Head studs, gaskets, bearings and the small stuff

Head studs come first. ARP 207-4203 is the M11 Evo head stud kit, and the VR4 uses the 12mm kit 207-4201. Main studs are ARP 207-5401 across the 4G63. There are also ARP cam sprocket bolts 107-1002 and flywheel bolt kits split by generation, 107-2801 for Evo 1 to 3 and 107-2803 for Evo 4 to 9. The full range is in ARP head studs.

Bearings are where the generations really separate. The 4B1185H rod bearing set covers the 4G63, but mains are 5M1186H for Evo 1 to 4 and 5M1219H for Evo 5 to 9, and the VR4 has its own 4B1146H rod and 5M1144H main sets. The ACL Race Series range lists them all. Order against the generation, not the engine name.

Then there is crank walk. The later 4G63 blocks have a reputation for it, and the ACL 1T1219 thrust washer set for Evo 5 to 9 goes into most of those rebuilds as standard practice. Get your engineer to measure crank end float before the block is machined, not after the pistons arrive.

Head gaskets are split the same way as the bearings. Cometic list a 1.3mm MLS at 86mm for Evo 4 to 9 as C4156-051 and a separate 1.3mm at 86mm for Evo 1 to 3 and VR4 as C4234-051, plus an exhaust gasket. Cometic head gaskets has the range.

The valvetrain is worth a paragraph on its own. GSC ZERO-TICK lifters for the 4G63T solve a noise and lash problem that people put up with for years, and GSC also make a Viton stem seal set covering Evo 1 to 9. Brian Crower list a 4G63 valve spring kit. Kelford make a balance shaft delete kit, KCG63 adjustable cam gears for Evo 1 to 8 and VR4, and a large range of camshafts, with the Evo 8 collection carrying both hydraulic and solid lifter profiles. GSC Mitsubishi cams covers billet camshafts for Evo 1 to 3, Evo 4 to 8, Evo 9 Mivec and the Evo X. Our Kelford cam selection guide will help you read the profiles before you commit.

Build it your way

Not every build fits a package. The Engine Builder lets you pick the engine then work through pistons, rods, bearings, gaskets and studs while keeping the combination consistent. It is the right tool for a stroker, a solid lifter head, or a low compression 4G63 built around one specific turbo.

Parts are catalogued by generation: Evo 1 to 3, Evo 4 and Evo 5 to 9. The 4G63 hub page is the overview.

Evo X owners are not left out. The 4B11 collection carries ARP head studs including the CA625+ kit 207-4207, main studs 207-5403, ACL rod bearings and thrust washers, CP pistons at 10.0:1, an ATI Super Damper, a Radium fuel rail and NGK plugs.

Where NZ Performance fits

We have been supplying performance parts from Palmerston North since 2003 and we race what we sell, which is why the advice on the phone is usually about what not to buy. 4G63 hardware is stocked in New Zealand where we can, so studs, bearings and gaskets normally ship the same or next working day instead of waiting weeks.

We get asked for a 4G63T engine for sale most weeks and the answer stays the same: we sell parts and packages, not complete engines. Rebuilding the block you have, or a used import block, is nearly always the cheaper path to a known engine. That comparison is written up in rebuild versus import, and if you are going hunting for boost afterwards, read head studs, gaskets and pistons for big boost first.

FAQ

What is in a 4G63 rebuild kit?

Our packages contain forged pistons, forged rods, a Cometic MLS or Tomei head gasket, ARP or Mazworx head and main stud kits, and ACL Race Series main and rod bearings. Each title states the piston brand, rod brand, gasket thickness where one is included, and the compression ratio. Lifters, springs, cam gears and service parts are listed separately under your generation.

Which 4G63 package suits my Evo?

They are split by generation because the parts genuinely differ. We list VR4, Evo 1 to 3, Evo 4, and Evo 5 to 9 packages. Main bearings, thrust washers, flywheel bolts and head gaskets all change across those groups, so order against the car you own.

8.5:1 or 9.0:1 compression on a 4G63?

The 8.5:1 builds suit a bigger turbo, more boost and the fuel available here, because the lower compression buys knock margin. The 9.0:1 builds keep response for a smaller turbo or a road car. CP also list Evo pistons on their own at 10.0:1 for higher compression builds.

Can I buy a complete 4G63 engine from NZ Performance?

No. We sell rebuild parts, packages and the Engine Builder, not complete or crate engines. Most people searching for a 4G63T for sale end up rebuilding their own block or a used import block, which costs less and gives you a known spec.

Why do people order thrust washers with an Evo 5 to 9 rebuild?

Crank walk. The later blocks carry their own main bearing and thrust washer part numbers, and the ACL 1T1219 set for Evo 5 to 9 goes into most of those rebuilds by default. Have crank end float measured before the block is machined.