Complete disassembly, inspection, machining, and rebuild of the 1.8L Nu engine including replacement of all wear components, precision assembly with torque-to-yield fasteners, and timing system installation.

Warnings

Tools required

Parts

• Complete engine gasket set × 1 — Use OEM specification
• Cylinder head gasket × 1 — Use OEM specification
• Piston ring set (all cylinders) × 1 — Use OEM specification
• Main bearing set (standard or oversized) × 1 — Use OEM specification
• Connecting rod bearing set (standard or oversized) × 1 — Use OEM specification
• Timing chain kit (chain, guides, tensioner) × 1 — Use OEM specification
• Oil pump assembly × 1 — Use OEM specification
• Water pump × 1 — Use OEM specification
• Thermostat and housing gasket × 1 — Use OEM specification
• Front crankshaft seal × 1 — Use OEM specification
• Rear crankshaft seal × 1 — Use OEM specification
• Valve stem seals (set of 16) × 1 — Use OEM specification
• Cylinder head bolts (TTY) × 1 — Use OEM specification
• Main bearing cap bolts (TTY) × 1 — Use OEM specification
• Connecting rod bolts (TTY) × 1 — Use OEM specification
• Oil filter × 1 — Use OEM specification
• Oil drain plug crush washer × 1 — Use OEM specification
• Spark plugs (set of 4) × 1 — Use OEM specification
• Engine coolant × 1 — Hyundai/Kia Long Life Green
• RTV silicone sealant × 1 — Kia OEM specification

Fluids

• Kia Genuine 5W-20 engine oil — 4.5 qt
• Hyundai/Kia Long Life Coolant (Green) — 7.5 qt

Preparation

1. Ensure vehicle is on level ground with wheel chocks applied and parking brake engaged
2. Disconnect negative battery cable and isolate it away from battery post
3. Drain engine oil completely and remove oil filter
4. Drain cooling system from radiator drain and engine block drain plugs
5. Remove engine cover and intake air duct assembly
6. Relieve fuel system pressure by removing fuel pump fuse and running engine until it stalls
7. Disconnect fuel lines, marking their positions for reinstallation
8. Label and disconnect all electrical connectors, vacuum lines, and coolant hoses from engine
9. Remove radiator, cooling fans, and A/C condenser for clearance
10. Disconnect exhaust system from manifold
11. Remove accessory drive belt and all belt-driven accessories (alternator, A/C compressor, power steering pump)
12. Support transmission with jack and remove engine-to-transmission bolts
13. Attach engine hoist to factory lifting points and take up slack
14. Remove engine mount bolts and carefully lift engine from vehicle
15. Mount engine securely on engine stand, ensuring proper weight distribution

Procedure

1. 1

   External component removal and cleaning
   Remove all external components from engine block: intake manifold, exhaust manifold, valve cover, timing cover, oil pan, oil filter housing, water pump, thermostat housing, and all sensors. Remove flywheel using holding tool. Clean all external surfaces thoroughly with brake cleaner and inspect for cracks or damage. Remove carbon deposits from combustion chambers visible through intake/exhaust ports.
   ⚠Apply penetrating oil to exhaust manifold nuts 24 hours before removal to prevent stud breakage.
   Torque spec

   Intake Manifold Bolts25 Nm (18 lb-ft)

   Exhaust Manifold Nuts30 Nm (22 lb-ft)

   Cover Bolts15 Nm (11 lb-ft)

   Flywheel Bolts95 Nm (70 lb-ft)

   Oil Pan Bolts12 Nm (9 lb-ft)
2. 2

   Cylinder head removal and disassembly
   Remove cylinder head bolts in reverse of tightening sequence (outside to center pattern). Carefully lift cylinder head from block, using plastic mallet to break gasket seal if needed. Place head on clean work surface. Remove camshafts by loosening bearing cap bolts in reverse sequence (outward from center) in multiple passes. Remove rocker arms, lash adjusters, and valve train components, keeping them organized by cylinder. Use valve spring compressor to remove valve keepers, springs, and valves. Keep all valves in order for inspection. Remove and discard valve stem seals.
   Torque spec

   Cylinder Head Bolts65 Nm (48 lb-ft)

   Camshaft Bearing Cap Bolts14 Nm (10 lb-ft)
3. 3

   Crankshaft and timing system removal
   Remove crankshaft pulley bolt using impact wrench or breaker bar with flywheel locked. Use harmonic balancer puller to remove crankshaft pulley. Remove timing cover bolts in sequence and remove cover. Remove timing chain tensioner, guides, and chain after marking timing alignment. Remove balance shaft assembly bolts and withdraw balance shaft. Rotate engine to access all main bearing cap bolts. Remove main bearing cap bolts in reverse order (outside to center) and carefully remove main bearing caps, keeping them in order and noting orientation. Lift crankshaft from block and set aside on clean surface.
   ⚠Main bearing caps are numbered and directional. Mark them clearly before removal if marks are not visible.
   Torque spec

   Crankshaft Pulley Bolt180 Nm (133 lb-ft)

   Cover Bolts15 Nm (11 lb-ft)

   Timing Chain Tensioner Bolt25 Nm (18 lb-ft)

   Timing Chain Guide Bolts12 Nm (9 lb-ft)

   Balance Shaft Bolts25 Nm (18 lb-ft)

   Main Bearing Cap Bolts75 Nm (55 lb-ft)
4. 4

   Piston and connecting rod removal
   Use ridge reamer to remove any ridge at top of each cylinder bore before piston removal. Rotate crankshaft to access each connecting rod. Mark connecting rods and caps with cylinder number and orientation using punch marks. Remove connecting rod cap bolts and caps. Push piston and rod assembly up and out of cylinder bore from below. Install rod caps back on matching rods immediately to prevent mixing. Inspect each piston for damage, scoring, or cracking. Remove piston rings using ring expander tool and discard rings.
   ⚠Never remove pistons without first removing cylinder ridge. This will damage rings and potentially crack piston ring lands.
   Torque spec

   Connecting Rod Bolts45 Nm (33 lb-ft)
5. 5

   Block inspection and machine shop preparation
   Remove all core plugs, oil gallery plugs, and remaining hardware from block. Clean block thoroughly in parts washer or with degreaser. Inspect cylinder walls for scoring, scuffing, or glazing. Use cylinder bore gauge to measure each cylinder in 3 locations (top, middle, bottom) and in 2 directions (parallel and perpendicular to crankshaft). Record measurements. Measure deck surface flatness with straightedge and feeler gauge. Inspect main bearing bores for damage. Clean all oil passages with rifle brushes and compressed air. Send block to machine shop with measurements for hot tank cleaning, magnaflux inspection, deck resurfacing, cylinder boring/honing to next oversize if needed, and align honing of main bearing bores if required.
   ℹ️Maximum cylinder bore taper is 0.05mm. Maximum out-of-round is 0.01mm. Exceeding these requires boring to next oversize.
6. 6

   Crankshaft and cylinder head machine work
   Measure all crankshaft main and rod journals with micrometer in multiple locations. Check for taper, out-of-round, and scratches. Measure crankshaft runout with V-blocks and dial indicator. Send crankshaft to machine shop for magnaflux inspection and grinding if journals are out of specification or damaged. For cylinder head, have machine shop perform valve job (resurface valves and seats), resurface deck if warped, and pressure test for cracks. Install new valve stem seals, guides if needed, and lap valves to seats. Verify valve spring heights and pressures.
   ℹ️Crankshaft journal out-of-round limit is 0.025mm. Surface finish after grinding must be 0.4 microns Ra or better.
7. 7

   Block reassembly preparation and bearing installation
   After receiving block from machine shop, clean thoroughly again with hot soapy water, rinse, dry with compressed air, and coat with light oil immediately. Install new core plugs and oil gallery plugs using appropriate sealant. Install oil pump pickup tube with new O-ring and torque bolts. Install new main bearings in block and caps, ensuring oil holes align and bearings seat fully in their bores without force. Install new connecting rod bearings in rods and caps. Do not oil bearings yet.
   Torque spec

   Oil Pump Pickup Tube12 Nm (9 lb-ft)
8. 8

   Crankshaft installation and bearing clearance check
   Place crankshaft carefully in block saddles. Install Plastigage strips on each main journal. Install main bearing caps in correct position and orientation. Torque main bearing cap bolts to specification in sequence (center outward) plus angle per TTY specification. Do not rotate crankshaft. Remove caps carefully and measure Plastigage width to determine bearing clearance. Clearance should be 0.02-0.04mm. If correct, remove Plastigage completely, oil all bearing surfaces liberally with assembly lube, reinstall crankshaft, and torque caps in sequence with new TTY bolts. Verify crankshaft rotates freely with no binding. Check crankshaft endplay with dial indicator (spec: 0.05-0.25mm).
   ⚠Main bearing clearance less than 0.015mm or greater than 0.06mm requires different bearings or crankshaft regrinding.
   Torque spec

   Main Bearing Cap Bolts75 Nm (55 lb-ft)
9. 9

   Piston and ring installation
   Install new piston rings on each piston using ring expander tool. Install oil control ring first (expander, then rails), then second compression ring, then top compression ring. Verify ring manufacturer's marks face upward. Check ring end gap in cylinder bore (should be 0.20-0.40mm for compression rings). Stagger ring gaps 120 degrees apart. Coat piston skirts, rings, and cylinder walls with assembly lube. Install connecting rod bearing inserts in rods. Attach connecting rod to piston with pin in correct orientation (mark on piston crown faces front, rod bearing tang slots face same direction). Install piston into correct cylinder using ring compressor, ensuring piston orientation mark faces front of engine. Guide rod over crankshaft journal.
   ⚠Incorrect ring gap staggering can cause excessive oil consumption. Incorrect piston orientation causes immediate engine damage.
10. 10

    Connecting rod bearing clearance and torquing
    With piston and rod installed in cylinder, install Plastigage on rod journal. Install rod cap in correct orientation and torque bolts to specification. Remove cap and measure clearance (spec: 0.020-0.041mm). If correct, clean Plastigage, apply assembly lube to bearings, install cap with new TTY bolts, and torque to specification plus angle. Repeat for all cylinders. Verify crankshaft still rotates freely after all rods are installed.
    ⚠Rod bearing clearance outside specification requires different bearings. Excessive clearance indicates journal damage.
    Torque spec

    Connecting Rod Bolts45 Nm (33 lb-ft)
11. 11

    Oil pump, pan, and front seal installation
    Install new oil pump assembly with new O-ring and torque bolts to specification. Verify pump rotates freely. Clean oil pan and block mating surfaces completely. Apply thin bead of RTV silicone to oil pan flange per factory pattern. Install oil pan and torque bolts in sequence from center outward. Install new front crankshaft seal using seal driver, ensuring it seats flush and square. Install balance shaft assembly with new bolts torqued to specification.
    ℹ️Allow RTV silicone to cure for 30 minutes before adding oil. Do not over-apply RTV as excess can block oil passages.
    Torque spec

    Oil Pump Bolts12 Nm (9 lb-ft)

    Oil Pan Bolts12 Nm (9 lb-ft)

    Balance Shaft Bolts25 Nm (18 lb-ft)
12. 12

    Timing chain system installation
    Rotate crankshaft to TDC cylinder 1 (mark on crankshaft gear at 12 o'clock). Install timing chain guides and torque bolts. Compress timing chain tensioner and install lock pin to hold it. Install tensioner and torque bolt. Drape timing chain over crankshaft gear, ensuring colored link aligns with mark. Route chain around guides. Install chain on camshaft gears (to be installed with cylinder head) with colored links aligned to gear marks. Verify all timing marks align before proceeding.
    ⚠️Incorrect timing chain installation will cause valve-to-piston contact and catastrophic engine damage upon startup.
    Torque spec

    Timing Chain Guide Bolts12 Nm (9 lb-ft)

    Timing Chain Tensioner Bolt25 Nm (18 lb-ft)
13. 13

    Cylinder head assembly and installation
    Assemble cylinder head: install valves with new seals, springs, retainers, and keepers using valve spring compressor. Install lash adjusters in their original positions (or new ones soaked in oil). Install rocker arms. Lubricate camshaft lobes and journals with assembly lube. Install camshafts in correct positions (intake and exhaust) with timing marks visible. Install camshaft bearing caps in sequence (numbered and directional) and torque in multiple passes from center outward. Verify camshafts rotate freely. Clean block deck and head surface. Place new head gasket on block (no sealant) with marks facing up. Install dowel pins if removed. Carefully lower head onto block. Install new TTY head bolts with light oil on threads. Torque in sequence (center outward, spiral pattern) in stages: 25 Nm, then 65 Nm, then +90 degrees, then +90 degrees additional.
    ⚠Head bolt torque sequence and angle specifications are critical. Improper torquing will cause head gasket failure.
    Torque spec

    Camshaft Cap Bolts14 Nm (10 lb-ft)

    Cylinder Head Bolts65 Nm (48 lb-ft)
14. 14

    External component installation and timing cover
    Verify timing chain is still properly aligned with marks on camshaft and crankshaft gears. Release timing chain tensioner lock pin. Clean timing cover mating surface and apply RTV to specified locations. Install timing cover with new gasket and torque bolts in sequence. Install crankshaft pulley with new bolt and torque to specification (may require angle torquing). Install water pump with new gasket/O-rings. Install thermostat and housing. Install valve cover with new gasket, torquing in sequence from center outward. Install intake manifold with new gaskets. Install exhaust manifold with new gaskets (apply anti-seize to studs) and torque nuts from center outward.
    Torque spec

    Cover Bolts15 Nm (11 lb-ft)

    Crankshaft Pulley Bolt180 Nm (133 lb-ft)

    Intake Manifold Bolts25 Nm (18 lb-ft)

    Exhaust Manifold Nuts30 Nm (22 lb-ft)
15. 15

    Flywheel, rear seal, and final assembly
    Install new rear main seal using seal driver. Install flywheel with new TTY bolts, using flywheel holding tool. Torque bolts in star pattern to specification plus angle if required. Install all sensors, sending units, and external components. Install new spark plugs. Rotate engine by hand at least two complete revolutions, checking for any binding or interference. Install new oil filter. Fill engine with specified oil quantity. Install engine in vehicle in reverse order of removal. Reconnect all wiring, hoses, fuel lines, exhaust, and accessories. Fill cooling system with specified coolant, burp air from system.
    ⚠Verify engine rotates freely by hand before installing in vehicle. Any resistance indicates assembly error.
    Torque spec

    Flywheel Bolts95 Nm (70 lb-ft)

    Oil Drain Plug35 Nm (26 lb-ft)

Reassembly

1. Reconnect all electrical connectors per labels and photographs taken during disassembly
2. Ensure all ground connections are clean and tight
3. Double-check all fluid levels before starting: engine oil, coolant, power steering, transmission
4. Verify all hose clamps are properly tightened and hoses are not kinked
5. Inspect for any tools or parts left in engine bay before closing hood
6. Reconnect negative battery cable last

Verification

• Before first start: verify oil pressure warning light illuminates with key on, engine off
• Initial start procedure: Prime oil system by cranking engine with fuel pump fuse removed and spark plugs removed until oil pressure gauge shows pressure
• First start: Start engine and immediately verify oil pressure. Engine should start within 5 seconds. Let idle for 30 seconds, then shut off
• Inspect for any oil, coolant, or fuel leaks while engine is running and after shutdown
• Second start: Run engine to operating temperature while monitoring temperature gauge and checking for leaks
• Perform break-in procedure: Vary RPM between 2000-4000 for first 30 minutes, avoid prolonged idle or full throttle
• Change oil and filter after first 500 miles of break-in period
• Monitor for unusual noises, vibrations, or warning lights during test drive
• Verify no check engine light and scan for any stored diagnostic codes
• Check all fluid levels again after test drive and verify no leaks
• Torque check critical fasteners (head bolts, main caps) after first heat cycle is not required with TTY fasteners, but verify valve cover, oil pan, and timing cover for any seepage

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