Mitsubishi 4G63T Rebuild, common faults & everything you need to know
Complete guide to the Lancer Evolution's legendary turbo four - a timing-belt-driven DOHC 16v with twin balance shafts. From 6-bolt to 7-bolt and 600-horsepower Evo builds, with factory-verified torque values and workshop prices.
We have built and rebuilt Mitsubishi's turbo four for decades. The 4G63T is the heart of the Lancer Evolution and the DSM cars (Eclipse, Talon, Laser) - a timing-belt-driven DOHC 16v with a cast iron block, aluminium cylinder head and twin balance shafts. The bottom end is famously strong and takes a lot of boost, but there are important differences between the generations: early engines (1990 to April 1992) have a 6-bolt crankshaft, while all Evo I-IX and later DSM have a 7-bolt crankshaft with different rotating characteristics. The 4G63T is also an interference engine, so a timing belt failure bends valves. We carry out everything from cylinder head reconditioning to complete engine reconditioning and turbo reconditioning with our own machine shop and a 12-month warranty.
The 4G63T at a glance
Data for the 4G63T (turbo). Torque values read from Mitsubishi's factory manuals (Lancer Evolution IV/V/VI and VIII Workshop Manual) and cross-verified.
| Variant | Year | Power | Torque | Crankshaft |
|---|---|---|---|---|
| Galant VR-4 / 1G DSM 6-bolt | 1988-1992 | 177-240 hk | 309 Nm | 6-bolt (early) |
| Lancer Evolution I-III 7-bolt | 1992-1996 | 250-270 hk | 309 Nm | 7-bolt |
| Lancer Evolution IV 7-bolt | 1996-1998 | 280 hk | 353 Nm | 7-bolt |
| Lancer Evolution V-VI 7-bolt | 1998-2001 | 280 hk | 373 Nm | 7-bolt |
| Lancer Evolution VII 7-bolt | 2001-2003 | 280 hk | 383 Nm | 7-bolt |
| Lancer Evolution VIII-IX 7-bolt MIVEC | 2003-2007 | 280-291 hk | 392 Nm | 7-bolt |
All JDM Lancer Evolution models were officially rated at 280 hp because of the Japanese 280 PS gentlemen's agreement. Real power climbed generation by generation, which shows in the rising torque figures (309 to 392 Nm). Power ranges and torque figures are identity data (Layer B), not factory-verified tightening torques.
Torque specs
Read from Mitsubishi's factory manuals (Lancer Evolution IV/V/VI ENGINE and Evolution VIII Group 11B Engine Overhaul) and cross-verified. Stretch bolts (cylinder head, main, connecting rod) are torqued by angle - always fit new ones. All verified values below come from 7-bolt manuals (Evo IV-IX); the main, connecting rod and flywheel torques for the 6-bolt engines are not factory-set here.
Cylinder head & valvetrain
Engine block & bottom end (7-bolt)
Timing belt, balance shafts & oil pump
Intake, exhaust & turbo
Note - Stretch bolts: cylinder head, main bearing and connecting rod bolts are angle-torqued stretch bolts (TTY). Mitsubishi specifies checking the bolt length (the cylinder head bolt service limit is 99,4 mm), and Meksta always fits new bolts on disassembly. The cylinder head is torqued using the plastic-region method: first 78 Nm in sequence, then fully loosened, then 20 Nm followed by two 90-degree angle steps. Each angle step must be at least 90 degrees - otherwise back off and start again.
Note - 6-bolt vs 7-bolt: all verified main, connecting rod and flywheel values above come from 7-bolt manuals (Evo IV-IX). The 6-bolt engines (Galant VR-4 and early 1G DSM, 1990 to April 1992) have thicker connecting rods, wider main bearing journals and 6 flywheel bolts - their torques may differ and must not be borrowed from the 7-bolt spec. On a 6-bolt rebuild we work to a 6-bolt-specific factory manual.
NOTE - Crankshaft centre bolt: 167 Nm applies to the later 7-bolt crankshafts (Evo VIII/IX) that have a large centre bolt. Early Evo IV/V use a keyed sprocket without a large centre bolt - check that the actual crankshaft really has the centre bolt before applying the torque. This is separate from the small crank pulley bolts (25 Nm).
Note - Turbo mounting varies: the turbocharger mounting torque differs between the manual generations. Evo IV/V/VI specifies 59 Nm on the exhaust manifold turbo side, while Evo VIII specifies 64 Nm for the turbocharger bolt/nut. Use the value for the generation you are servicing. The supporting turbo pipes (oil return pipe 9 Nm, heat shield 14 Nm) match across the generations.
Note - Timing belt & balance shafts: the 4G63T is an interference engine with a timing belt that drives both camshafts, the oil pump and the twin counter-rotating balance shafts. We always replace the timing belt, balance shaft belt, tensioner and water pump together at rebuild. The replacement interval is roughly 100 000 km or 7-8 years.
Factory tolerances (bearing clearance, deck height, piston clearance) for the 4G63T are documented separately and published once they are cross-verified. All measurements are checked against factory tolerances with our own machine shop.
Common faults on the 4G63T
This is what we see most often when a 4G63T comes in. Symptoms, causes and how we fix it.
Crank end float (7-bolt crank walk)
Common on 7-bolt • Critical- Symptoms
- The crankshaft walks axially (crank walk), erratic ignition, the crank sensor loses signal, the engine can suddenly die. Metal debris in the oil.
- Cause
- The 7-bolt crankshaft has a narrower thrust bearing than the 6-bolt. Under high load, a worn clutch or hard clutch release the thrust bearing wears and the crankshaft starts to walk. A notorious 7-bolt problem on hard-driven Evo/DSM.
Timing belt and balance shaft belt failure
Neglected maintenance • Critical- Symptoms
- Sudden engine stop, bent valves, loss of compression. The balance shaft belt can snap and be drawn into the timing belt, taking the whole timing with it.
- Cause
- An aged timing belt or balance shaft belt (the inner belt) that snaps. The 4G63T is an interference engine, so a belt failure means immediate valve contact. The inner balance shaft belt is notorious for being overlooked.
Head gasket & overheating
High boost / track • High- Symptoms
- White smoke, coolant in the oil, pressure build-up in the cooling system, overheating. Compression leaking between cylinders on tuned engines.
- Cause
- High cylinder pressures from raised boost, detonation or neglected cooling lift the head gasket. Common on tuned 4G63T. Often leads on to flatness errors and the need for resurfacing.
Turbo wear & oil leakage in the turbo
High mileage • High- Symptoms
- Blue smoke, oil consumption, axial play in the turbo shaft, whistling or scraping noise, falling boost. Oil in the intercooler pipes.
- Cause
- Worn turbo bearings after high mileage, neglected oil changes or hard running without a cool-down. The TD05 turbo wears in the shaft and starts leaking oil past the seals.
Detonation & piston damage
Bad map / poor fuel • Critical- Symptoms
- Knock under load, power loss, in the worst case a hole in a piston or damaged ring lands. Melt marks on the spark plugs.
- Cause
- A mixture that is too lean, too much ignition advance, low-octane fuel or too much boost. The ring lands on stock pistons only take so much before detonation damages the pistons. Common on poorly mapped builds.
Big-end and main bearing wear
High mileage • Critical- Symptoms
- A knocking noise from the lower engine under load, low oil pressure, metal shavings at oil changes.
- Cause
- Worn bearing shells after high mileage, oil starvation under hard driving or neglected oil maintenance. Requires crankshaft grinding and new bearings.
4G63T rebuild prices
Prices based on 4G63T specifications: 4 cyl inline, 85 mm bore, 16 valves, 5 main bearings + 4 big-end bearings. We carry out cylinder boring, crankshaft grinding and cylinder head resurfacing with our own machine shop. All prices exclude VAT and parts.
Cylinder head reconditioning
Bottom end
Full rebuild
Performance
Cylinder machining (4 cyl, 85 mm bore)
| Service | Price |
|---|---|
| Cylinder boring 4 cyl inline block (85 mm) | 3 318 kr |
| Plateau honing 4 cyl | 1 050 kr |
| Torque-plate boring 4 cyl (high-boost) | 4 603 kr |
| O-ringing block 4 cyl (high-boost) | 2 800 kr |
| Deck decking block 4 cyl | 1 974 kr |
Crankshaft work (5 main + 4 big-end, 8 counterweights)
| Service | Price |
|---|---|
| Crankshaft grinding (5 main + 4 big-end) | 3 010 kr |
| Polishing standard | 1 022 kr |
| Cleaning 4-cyl crankshaft | 784 kr |
| Straightening (medium) | 1 190 kr |
| Camshaft journal grinding 10 pcs (DOHC) | 3 080 kr |
| Remove/fit counterweights 8 pcs | 2 044 kr |
Valve reconditioning (16 valves)
| Service | Price |
|---|---|
| Cutting 16 valve seats (standard) | 1 820 kr |
| Cutting 16 valve seats (large) | 2 772 kr |
| Valve guide replacement 16 pcs (light alloy) | 2 548 kr |
| Manufacture of valve seat inserts 16 pcs | 3 080 kr |
| Bronze sleeves fitting 16 pcs | 2 268 kr |
Cylinder head resurfacing (4 cyl, standard head size)
| Service | Price |
|---|---|
| Resurfacing cylinder head 4 cyl (standard) | 1 330 kr |
| Resurfacing cylinder head 4 cyl (large) | 1 596 kr |
| Resurfacing block 4 cyl (standard) | 1 988 kr |
| Resurfacing block 4 cyl (large) | 2 114 kr |
| Resurfacing manifold 4 cyl | 2 842 kr |
Con-rod work (4 pcs)
| Service | Price |
|---|---|
| Replace con-rod bush 4 pcs | 2 240 kr |
| Manufacture con-rod bush 4 pcs | 2 898 kr |
| Length adjustment con-rod 4 pcs | 2 898 kr |
| Replace press-fit piston 4 pcs | 1 582 kr |
| Replace piston ring 4 pcs | 1 106 kr |
| Resizing big-end housing 4 pcs | 2 352 kr |
| Check/straighten con-rod 4 pcs | 1 414 kr |
| Full reconditioning con-rod 4 pcs | 3 164 kr |
| Steel shot peening con-rods 4 pcs | 2 268 kr |
Pressure testing & balancing
| Service | Price |
|---|---|
| Pressure testing cylinder head 4 cyl (small) | 1 876 kr |
| Pressure testing cylinder head 4 cyl (large) | 2 800 kr |
| Pressure testing cylinder block | 1 400 kr /h |
| Balancing rotating assembly straight 4-cyl | 3 742 kr |
| Weight matching con-rods 4 pcs | 1 316 kr |
| Weight matching pistons 4 pcs | 1 092 kr |
| Flywheel balancing | 2 100 kr |
| Balancing flywheel + clutch | 2 842 kr |
Indicative prices for the 4G63T configuration (4 cyl inline, 85 mm bore, 16 valves, alloy cylinder head, cast iron block). Labour prices exclude VAT and parts (piston rings, bearings, gaskets, stretch bolts, turbo parts). We always replace the timing belt, balance shaft belt and tensioner at rebuild. Request a quote for an exact price after inspection.
Tuning the 4G63T
The 4G63T is one of the most tunable turbo engines in the world. The cast bottom end takes a lot of boost, and the big power comes from a larger turbo, fuelling and - at high levels - forged internals.
- 1
Boost, intake, exhaust & remap
A freer intake and exhaust system, intercooler, raised boost and a properly worked remap give a solid gain on the stock parts while keeping reliability.
300-340 hk - 2
Larger turbo + fuelling
A larger turbo, upgraded injectors and fuel pump plus a reconditioned or upgraded turbo. The stock bearings handle this level well with the right margins and crank walk kept in check.
380-450 hk - 3
Forged internals + large turbo
Forged pistons and con-rods, ARP bolts, balancing and a larger turbo. Here the power window opens up significantly and the bottom end takes serious boost.
450-550 hk - 4
Full build
A complete bottom end, ported cylinder head, big turbo and race fuel for track and drag. We build the whole chain in-house with performance engine building.
600+ hk
Questions & answers about the 4G63T
What we hear most often from 4G63T owners.
What does it cost to rebuild a Mitsubishi 4G63T?
A cylinder head reconditioning costs about 5 000 - 7 000 SEK (labour), a complete engine reconditioning about 19 500 - 30 500 SEK. On top of that come parts (gasket, bearings, piston rings, stretch bolts, timing belt and balance shaft belt), typically 8 000 - 22 000 SEK depending on condition and variant. The turbocharger and turbo parts may be added. We give a fixed quote after inspection.
What is the difference between 6-bolt and 7-bolt 4G63?
The difference is in how the flywheel bolts to the crankshaft. The 6-bolt (1990 to late April 1992, early Galant VR-4 and early 1G DSM) has 6 flywheel bolts, thicker connecting rods and wider main bearing journals - regarded as the stronger bottom end. The 7-bolt (May 1992 onwards, all Lancer Evolution I-IX) has 7 flywheel bolts and lighter connecting rods, but a narrower thrust bearing that can cause crank walk. The crankshafts are not interchangeable between generations.
Is the 4G63T an interference engine?
Yes. The 4G63T is an interference engine with a timing-belt-driven DOHC. If the timing belt snaps or jumps, the valves hit the pistons, which bends valves and often causes secondary damage. The timing belt should be replaced every 100 000 km or every 7-8 years. We always replace the timing belt, balance shaft belt, tensioner and water pump together at rebuild.
What is crank walk on the 7-bolt 4G63?
Crank walk is when the crankshaft starts to walk axially because the thrust bearing has worn. It mainly affects 7-bolt engines, which have a narrower thrust bearing than the 6-bolt. Symptoms are erratic ignition, the crank sensor losing signal and in the worst case engine failure. A worn clutch, hard clutch release and high load speed it up. We measure the crankshaft end float against factory tolerance on every rebuild.
How much power can a 4G63T handle?
A stock bottom end reliably handles 350-400 hp with a larger turbo, fuelling and a healthy map - provided crank walk is kept under watch. With forged pistons, connecting rods and ARP bolts you build 450-550 hp, and with a full build and big turbo 600+ hp. The 7-bolt bottom end is a popular base for big power builds.
How long does a rebuilt 4G63T last?
With a correct rebuild, a healthy map and regular maintenance: 200 000 - 300 000 km or more on a street car. The bottom end is durable. Keep an eye on the timing belt and balance shaft belt, the turbo's condition, oil changes and the crankshaft end float, and the 4G63T is a very durable turbo engine.
Do you rebuild the turbo as well?
Yes. We carry out turbo reconditioning on TD05-family units and can also help with a turbo upgrade alongside an engine build. Worn bearings, axial play and oil leakage are put right, and we balance the rotor. On a complete build we plan the turbo choice around the target power.
Should you rebuild or replace the engine?
For the 4G63T: usually rebuild, especially if you want a known and controlled bottom end ahead of a power build. A used Evo/DSM engine has unknown history and the same wear points (crank walk, timing belt, turbo). A rebuilt engine has known tolerances, new wear parts and a 12-month warranty. We ship worldwide.
See also: another iconic four-cylinder engine we rebuild is the Toyota 4A-GE. For turbo builds we also help with turbo reconditioning. We service everything from Japanese turbo fours to European sixes.
Do you have a 4G63T that needs looking at?
Call us directly or send in a quote request. We reply within 24 hours.