Segment:
Luxury Executive Saloon, distinct from Jaguar's sports cars but sharing engineering.
Target Audience:
Buyers seeking a comfortable, powerful, and stylish luxury vehicle with a sporting edge.
Key Competitors:
Rover P5B, Daimler 2.5 V8/250, Bentley 'S' Type, Mercedes-Benz W108/W109.
Design Philosophy:
Elegant styling, powerful XK engine, comfortable ride, and sophisticated handling for its era.
Model Distinction:
The 420/420G represented a more performance-oriented and luxurious iteration compared to the Mark 2, bridging the gap to the XJ6.
Primary Coverage:
Comprehensive mechanical, electrical, and bodywork service and repair.
Additional Coverage:
Includes troubleshooting, diagnostics, and specifications for all major systems.
Estimated Page Count:
Approx. 500-700 pages (variable depending on specific edition/format)
Type:
Workshop Service and Repair Manual
Format:
Digital (likely PDF, printable)
Engine:
XK Series Inline-6 (3.8L, 4.2L), including carburetion (SU/Zenith Stromberg), ignition, cooling, lubrication, and exhaust.
Transmission:
Manual (Moss/Jaguar Gearbox), Automatic (Borg-Warner Model 8 / Model 35).
Drivetrain:
Rear-wheel drive, differential, half-shafts, driveshaft.
Suspension:
Front independent (double wishbone, torsion bars), Rear independent (semi-trailing arms, coil springs).
Brakes:
Girling Hydraulic Disc Brakes (front and rear), Handbrake mechanism.
Steering:
Burman Recirculating Ball Power Steering (optional/standard depending on model/market).
Electrical:
12V System, Lucas components (alternator/dynamo, starter, ignition, lighting, wiring diagrams).
Fuel System:
Fuel tanks, pumps (mechanical/electric), lines, carburettor setup.
Bodywork And Chassis:
Body shell construction, panels, doors, windows, trim, upholstery.
Maintenance:
Routine servicing, lubrication schedules, fluid changes, filter replacements.
Repair:
Engine overhaul, gearbox rebuilds, brake caliper overhaul, suspension component replacement.
Troubleshooting:
Diagnostic charts for common faults, symptom-based analysis.
Diagnostics:
Ignition timing, carburettor tuning, electrical circuit testing.
Installation Adjustment:
Component fitting, alignment procedures, calibration.
Depth:
Comprehensive, suitable for professional mechanics and experienced DIY enthusiasts.
Detail Level:
Includes detailed diagrams, torque specifications, clearances, and exploded views.
Engine Family:
Jaguar XK Inline-6
Engine Codes:
4.2 Litre (e.g., 7007/7009 series for 420G, similar for 420 with potentially minor differences).
Displacement Litres:
4.2 L
Bore X Stroke Mm:
92.07 x 106.0 mm
Compression Ratio:
8.0:1 or 9.0:1 (depending on variant)
Horsepower Bhp:
Approx. 245 bhp (420G), Approx. 265 bhp (420 - higher compression, dual exhaust)
Torque Lb-Ft:
Approx. 285 lb-ft (420G), Approx. 280 lb-ft (420)
Carburettors:
Twin SU HD6 (420) or Triple SU HD8 (420G).
Fuel Type:
Premium Unleaded Gasoline (Octane rating appropriate for era, leaded initially).
Ignition System:
Lucas Distributor with points and coil.
Transmission Type:
4-speed Manual with Overdrive (Laycock de Normanville Type GH) often standard on 420.
Transmission Type:
3-speed Automatic (Borg-Warner Model 35, often standard on 420G).
Overdrive Operation:
Electric switch control for engaging/disengaging overdrive.
Manual Transmission Fluid:
GL4 Gear Oil, e.g., SAE 80/90 (check manual for precise type).
Automatic Transmission Fluid:
Dexron II or equivalent (check manual for precise type).
Crash Test Data:
No modern standardized crash test data available for this era; built to contemporary standards.
Braking System:
Girling hydraulic disc brakes on all four wheels, power-assisted.
Steering Features:
Optional power steering for improved maneuverability.
Seatbelts:
Lap belts often standard; shoulder belts may have been optional or fitted later.
Construction:
Unitary body construction (monocoque) with subframes for engine/suspension.
Audio System:
Period-correct AM/FM radio, likely Lucas or similar period manufacturer. Cassette players and later upgrades may exist.
Dashboard Controls:
Classic analogue instrumentation, central dashboard layout with heater and ventilation controls.
Parking Aids:
None originally fitted; parking sensors are aftermarket additions.
Cruise Control:
Optional on some models, typically mechanical systems.
Original Connectivity:
N/A (No electronic connectivity in the modern sense).
Oil Change:
Every 3,000 miles or 6 months (recommendation, check manual for exact spec).
Grease Points:
Regular lubrication of suspension and steering components (e.g., every 1,000-2,000 miles).
Tune Up:
Periodic checks of ignition timing, carburettor synchronization, and valve clearances.
Engine Oil Capacity Litres:
Approx. 7.7 litres (with filter change).
Engine Oil Grade:
e.g., SAE 20W-50 or 20W-40 (check manual for specific climate/era recommendation).
Coolant:
Water/Glycol mixture (50/50), check manual for approved coolant types.
Brake Fluid:
DOT 3 or DOT 4 Hydraulic Brake Fluid (check manual for specific DOT rating).
Rust Prone Areas:
Wheel arches, sills, boot floor, A-posts, jacking points.
Common Wear Items:
Bushings (suspension/steering), heater matrix, water pump, kingpins, exhaust system.
Carburettor Issues:
Sticking pistons, worn needle valves, vacuum leaks, synchronization drift.
Electrical Quirks:
Lucas components can be prone to failure; wiring insulation degradation over time.
Manufacturer Origins:
Jaguar Cars Ltd., founded by Sir William Lyons, renowned for sports cars and luxury sedans.
Predecessors:
Evolved from the Jaguar Mark 2 and S-Type, incorporating styling cues from the XJ6.
Development Context:
Developed as a more modern and spacious luxury saloon to complement Jaguar's sports car line-up and compete with contemporary rivals.
Production Period:
1966-1970
Manufacturing Location:
Coventry, England
Production Volume:
Approx. 12,000 combined units (420 and 420G).
Contemporary Reviews:
Generally praised for performance, styling, and luxury for its price point, though some criticized ride quality compared to rivals.
Market Perception:
Considered a desirable classic luxury saloon, offering significant performance for its class.
Heritage Status:
Recognized as a significant model in Jaguar's history, embodying the brand's mid-to-late 60s luxury executive car era.
