Overview
The 2.0L OHC (Overhead Camshaft) engine is the heart of the Corris Rivett. Based on the legendary Ford Pinto engine (TL20H variant), this powerplant produces approximately 99 hp @ 5500 RPM and 154 Nm @ 3700 RPM in stock configuration.
Unlike older pushrod designs, the OHC architecture uses a belt-driven camshaft in the cylinder head to actuate valves directly via rocker arms. This allows for better high-RPM performance but introduces the critical risk of timing belt failure.
Engine Specifications
| Specification | Value | |---------------|-------| | Displacement | 1993cc (2.0L) | | Configuration | Inline-4 Cylinder | | Valvetrain | SOHC (Single Overhead Cam) | | Horsepower | 99 hp @ 5500 RPM | | Torque | 154 Nm @ 3700 RPM | | Compression | 9.2:1 (stock) | | Fuel System | Single-barrel carburetor | | Ignition | Points/Electronic distributor | | Firing Order | 1-3-4-2 |
Block Assembly
Engine Block
The cast-iron engine block is the heaviest single component and the foundation for the entire powertrain.
Key Features:
- Houses 4 cylinders for combustion
- Contains main bearing journals for crankshaft
- Features auxiliary shaft (unique to OHC design)
- Wearable - Check for cracks and cylinder wear
Auxiliary Shaft System
The Aux Shaft is unique to this engine architecture (replaces the in-block camshaft of pushrod engines).
| Function | Description | |----------|-------------| | Oil Pump Drive | Spins the oil pump | | Fuel Pump Eccentric | Lobe pushes mechanical fuel pump | | Distributor Drive | Gear meshes with distributor |
Warning: If the aux shaft isn't rotating, the engine has spark and compression but NO fuel delivery!
Crankshaft & Bearings
| Component | Bolt Size | Notes | |-----------|-----------|-------| | Main Bearing Caps | 14mm | Torque sequence critical | | Rod Caps | 10-11mm | Connect pistons to crank |
Wear Indicators:
- Deep "thudding" knock = worn main bearings
- Rattling knock = worn rod bearings
- Visual: Inspect journals for scoring
Pistons
- Material: Aluminum
- Damageable: Yes (detonation, overheating)
- Installation: Valve reliefs must face correct direction
- Wear Signs: Blackened or scarred tops = damage
Cylinder Head & Valvetrain
Cylinder Head
The cast-iron head creates the upper combustion chamber and houses the camshaft.
| Component | Bolt Size | Notes | |-----------|-----------|-------| | Head Bolts | 12-13mm | Tighten center-out spiral | | Head Gasket | N/A | One-time use, replace if removed |
Head Gasket Failure Symptoms
| Symptom | Indication | |---------|------------| | White exhaust smoke | Coolant burning | | "Mayonnaise" in oil | Coolant mixing with oil | | Bubbles in radiator | Combustion gases in coolant | | Overheating | Compression leak |
Camshaft
- Location: Towers cast into cylinder head
- Drive: Belt-driven via camshaft sprocket
- Adjustment: Valve lash via rocker arm screws
Valve Lash Effects:
| Condition | Symptom | Result | |-----------|---------|--------| | Too Loose | Ticking noise | Reduced valve lift, power loss | | Too Tight | Quiet but wrong | Burnt valves, compression loss |
Timing Belt System (CRITICAL)
The 2.0L OHC is an INTERFERENCE ENGINE. This is the most critical system to understand.
What "Interference" Means
The valves and pistons occupy the same space at different times. The timing belt keeps them synchronized. If the belt breaks:
- Camshaft stops rotating
- Crankshaft keeps spinning
- Pistons smash into open valves
- CATASTROPHIC ENGINE DAMAGE
Timing Components
| Part | Bolt Size | Function | |------|-----------|----------| | Timing Belt | Tensioner | Synchronizes cam/crank | | Camshaft Sprocket | 17mm | Drives camshaft | | Crankshaft Sprocket | N/A | Driven by crank | | Aux Shaft Sprocket | N/A | Drives aux shaft | | Tensioner Pulley | 13mm | Maintains belt tension |
Timing Alignment Procedure
- Crankshaft: Rotate until TDC mark aligns with block pointer
- Camshaft: Align arrow on cam sprocket with dot on head casting (6 o'clock position)
- Install Belt: Route around all sprockets
- Tension: Adjust tensioner, lock bolt
Belt Replacement Interval
- Preventative replacement is essential
- Replace before visible wear/cracking
- One of the most important maintenance items
Fuel & Induction
Carburetor
The single-barrel downdraft carburetor uses the Venturi effect to draw fuel.
| Aspect | Detail | |--------|--------| | Mounting | 4x 8mm nuts to intake | | Air Filter | MANDATORY - protects cylinders | | Tuning Screw | Adjusts air-fuel ratio |
Air-Fuel Ratio Tuning
| AFR | Condition | Effect | |-----|-----------|--------| | 14.7:1 | Stoichiometric | Ideal (warm weather) | | 13.5-14.0 | Rich | Winter setting (recommended) | | 15.0+ | Lean | Overheating risk |
Tuning Procedure:
- Scroll Down = Enrich (more fuel)
- Scroll Up = Lean (more air)
Winter Tip: Cold air is denser. A carb tuned for 14.7 in warm garage will run LEAN (~16.0) outside in -20°C!
Fuel Pump
- Type: Mechanical
- Location: Side of block
- Drive: Eccentric lobe on aux shaft
- Bolt Size: 10mm
Cooling System
Components
| Part | Bolt Size | Wearable | Notes | |------|-----------|----------|-------| | Water Pump | 10mm | Yes | Belt-driven, circulates coolant | | Thermostat | Housing | Yes | Regulates flow to radiator | | Radiator | N/A | Yes | Front-mounted heat exchanger | | Radiator Hoses | Clamps | Yes | Top and bottom, check for cracks |
Thermostat Failure
| Condition | Effect | |-----------|--------| | Stuck CLOSED | Engine overheats rapidly | | Stuck OPEN | Never reaches operating temp, NO CABIN HEAT |
Winter Warning: A stuck-open thermostat means you freeze in the cabin and your windshield fogs up!
Electrical Components
Alternator
| Detail | Specification | |--------|--------------| | Mounting | Bracket with pivot | | Bolts | 13mm, 10mm | | Belt | Drives alternator + water pump | | Wearable | Yes |
Alternator Belt Tension
Symptoms of Loose Belt:
- Squealing noise
- Battery not charging
- Water pump slowing (overheating)
Tensioning Procedure:
- Loosen mounting bolts
- Pull alternator away from engine
- Tighten bolts while holding tension
Warning: Over-tightening damages water pump and alternator bearings!
Starter Motor
- Location: Bellhousing
- Bolt Size: 13mm
- Wearable: Yes (high load in winter)
- Wiring: Heavy positive from battery + signal from ignition
Transmission Options
Manual Gearbox
| Option | Gears | Notes | |--------|-------|-------| | 4-Speed | Standard | Robust, higher cruising RPM | | 5-Speed | With overdrive | Better highway efficiency |
Manual Components
| Part | Bolt Size | Wearable | |------|-----------|----------| | Clutch Disc | N/A | Yes - friction material wears | | Pressure Plate | 10mm | No | | Flywheel | 17mm | No | | Gearbox | 13-14mm | Yes |
Automatic Option
- Type: 3-Speed torque converter
- Fluid: ATF (Automatic Transmission Fluid)
- Note: Makes rocking out of snow harder vs manual clutch control
Drivetrain
Driveshaft
| Detail | Specification | |--------|--------------| | Bolt Size | 11-12mm (differential flange) | | Wearable | Yes (U-joints wear) | | Symptom | Vibration at speed if damaged |
Rear Axle
- Type: Live axle (solid unit)
- Differential: Open or LSD (randomized by trim)
- LSD Advantage: Both wheels spin, better traction in snow
Troubleshooting Guide
Start-Up Issues
| Symptom | Cause | Fix | |---------|-------|-----| | Slow cranking | Battery cold/dead, thick oil | Charge battery, use winter oil | | Fires then dies | Choke not pulled, vacuum leak | Check choke, tighten intake | | Backfiring | Timing off | Rotate distributor, check belt |
Fluid Leaks
| Color | Fluid | Check | |-------|-------|-------| | Blue/Green | Coolant | Radiator hoses, water pump | | Black/Brown | Oil | Oil pan, valve cover, filter | | Clear/Yellow | Brake fluid | Master cylinder, calipers |
Engine Noises
| Sound | Likely Cause | |-------|--------------| | Deep thud | Worn main bearings | | High knock | Rod bearing wear | | Ticking | Loose valve lash | | Squeal | Loose alternator belt |
Assembly Tips
Critical Torque Sequences
- Main Bearing Caps: Center-out pattern
- Head Bolts: Spiral from center outward
- Rod Caps: Equal torque both sides
Visual Inspection
Before installing used parts:
- Smooth, polished surfaces = Good
- Scored, gray, scuffed surfaces = Will fail
Winter Assembly Notes
- Use winter-weight oil (5W-30 or 0W-30)
- Tune carburetor rich (13.5-14.0 AFR)
- Ensure block heater is functional
- Check all rubber components for cold cracking
INTERFERENCE ENGINE
The 2.0L OHC is an interference engine. If the timing belt snaps, the pistons WILL hit the valves, destroying the cylinder head and pistons. Replace the timing belt preventatively!
Winter Carburetor Tuning
Cold air is denser than warm air. Tune the carburetor slightly rich (AFR 13.5-14.0) to compensate. A lean mixture in winter causes overheating and piston damage.