Porsche 904

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Porsche 904: A Comprehensive Guide

The Porsche 904, officially the Porsche Carrera GTS, stands as a testament to Porsche's relentless pursuit of engineering excellence in the early to mid-1960s. It was a pivotal car, bridging the gap between the road-going 356/911 and the uncompromising racing prototypes like the 906. This guide delves into the history, generations, reliability, driving experience, and buying advice for this iconic machine.

Introduction

The 904 was introduced in late 1963 for the 1964 racing season to comply with FIA's Group 3 homologation regulations, requiring a minimum production of 100 cars. It was designed by Ferdinand Alexander "Butzi" Porsche (who also designed the 911) and marked a significant departure from previous Porsche designs. It was intended to be a dual-purpose vehicle: both a competitive race car and a usable, if uncompromising, road car. The 904's fiberglass body, bonded directly to a steel ladder chassis, was a cutting-edge approach at the time and contributed significantly to its low weight. It was initially powered by the Porsche 587/3 four-cam, four-cylinder engine.

The 904 competed in the FIA GT category and achieved considerable success in international motorsport, securing victories in prestigious events such as the Targa Florio and Spa-Francorchamps. Its blend of relatively simple mechanics (especially compared to contemporary Formula 1 cars), light weight, and excellent aerodynamics made it a formidable competitor.

Generations

First Generation (1964-1965)

• Years: 1964-1965
• Engine: Initially, the Porsche 587/3, a 1966 cc four-cam, four-cylinder engine producing around 180 horsepower. This was the most common configuration.
• Key Changes: Very few changes occurred during the brief production run. Some cars received factory upgrades or modifications for specific races. These might include subtle aerodynamic tweaks, different gear ratios, or improved cooling.
• Variations: A small number of 904s were equipped with the six-cylinder engine from the Porsche 911 (designated the 904/6) and an even smaller handful were fitted with the eight-cylinder engine from the Porsche 908 (although these were primarily testbeds and not sold commercially). The 904/6 is a highly desirable and significantly more powerful version.

Reliability & Common Issues

Engine

The Porsche 587/3 engine, while potent, is complex and requires specialized knowledge for maintenance and repair. It's a dry-sump engine with four overhead camshafts, a design that demands precise timing and lubrication. A poorly maintained 587/3 can suffer from camshaft wear, valve issues, and oil leaks.

• Potential Problems:
  • Camshaft Wear: Insufficient or contaminated oil can lead to rapid camshaft wear. Regular oil changes and meticulous maintenance are crucial.
  • Valve Issues: The complex valve train can be prone to issues if not properly adjusted.
  • Oil Leaks: Dry-sump systems are inherently prone to leaks, particularly from seals and connections.
  • Carburetor Problems: The Weber carburetors require regular tuning and cleaning to ensure optimal performance.
• Solutions: Seek out a mechanic specializing in vintage Porsche engines, especially those familiar with the four-cam design. Regular maintenance, including oil changes, valve adjustments, and carburetor tuning, is essential.

Chassis & Body

The 904's chassis is a steel ladder frame, which is relatively robust. However, the fiberglass body can be susceptible to damage, especially in accidents. Finding replacement body panels or skilled repair technicians can be challenging and expensive.

• Potential Problems:
  • Fiberglass Cracks and Damage: The fiberglass body is prone to cracking, especially around mounting points. Impacts can cause significant damage.
  • Corrosion: The steel chassis can corrode, particularly in areas exposed to moisture and road salt.
  • Suspension Wear: The suspension components, including the dampers, springs, and bushings, will wear over time and require replacement or rebuilding.
• Solutions: Thoroughly inspect the body for cracks and damage. Look for signs of corrosion on the chassis, especially in the wheel wells and around the suspension mounting points. Suspension components should be inspected for wear and play.

Other Systems

Other areas to consider include the braking system, electrical system, and transaxle. The brakes are generally reliable, but the master cylinder and calipers can require rebuilding over time. The electrical system is relatively simple but can suffer from wiring issues and corrosion. The transaxle is generally robust, but regular fluid changes are essential to prevent wear.

• Potential Problems:
  • Brake System Issues: Leaks in the brake lines, worn-out master cylinder, and seized calipers are common problems.
  • Electrical System Issues: Corroded wiring, faulty switches, and a weak generator or alternator can cause electrical problems.
  • Transaxle Wear: Worn synchros and bearings can cause shifting difficulties.
• Solutions: Regularly inspect the brake system for leaks and wear. Ensure the electrical system is properly maintained. Change the transaxle fluid at recommended intervals.

Driving Experience

Driving a Porsche 904 is an experience unlike any other. It's a raw, visceral connection to a bygone era of motorsport. The light weight, responsive handling, and direct steering make it incredibly agile and rewarding to drive on a winding road or race track. However, it's also a demanding car that requires respect and skill to master.

Pros:

• Exceptional Handling: The 904's low weight and well-sorted suspension provide exceptional handling and cornering abilities.
• Responsive Engine: The four-cam engine is incredibly responsive and delivers exhilarating acceleration.
• Direct Steering: The unassisted steering provides precise and communicative feedback.
• Iconic Design: The 904's striking design is instantly recognizable and commands attention.
• Rarity: Owning a 904 places you in a very exclusive club.

Cons:

• Unforgiving: The 904 is a demanding car that can be unforgiving to drive, especially at the limit.
• Limited Comfort: The interior is spartan and lacks creature comforts.
• Noise: The engine and exhaust are loud, making it unsuitable for long journeys.
• Maintenance Costs: Maintaining a 904 can be expensive due to the specialized parts and expertise required.
• Value: Highly sought-after means high price.

Buying Advice

Buying a Porsche 904 is a significant investment, both financially and emotionally. Due to their rarity and historical significance, they command a premium price. Thorough due diligence is essential to ensure you are purchasing a genuine and well-maintained example.

What to Look For:

• Originality: Verify the car's originality, including the engine, chassis, and body. Check the chassis number against Porsche records to confirm its authenticity.
• Service History: Obtain a complete service history to assess the car's maintenance record.
• Condition: Thoroughly inspect the car for signs of damage, corrosion, and wear. Pay particular attention to the fiberglass body, chassis, and engine.
• Expert Inspection: Have the car inspected by a Porsche specialist who is familiar with the 904.
• Documentation: Review all available documentation, including the original bill of sale, ownership history, and maintenance records.

What to Avoid:

• Cars with Extensive Accident Damage: Avoid cars that have been heavily damaged in accidents, as the repairs can be difficult and expensive.
• Cars with Incorrect or Non-Original Parts: Be wary of cars with incorrect or non-original parts, as this can detract from their value and authenticity.
• Cars with Poor Maintenance Records: Avoid cars with poor maintenance records, as this can indicate potential problems down the road.
• Cars Being Sold at Significantly Below Market Value: If a deal seems too good to be true, it probably is. Be cautious of cars being sold at significantly below market value, as they may have hidden problems.

Years to Consider:

All 904s are desirable, however, the 904/6 represents a significant performance increase due to the 6-cylinder engine. Expect to pay a substantial premium for a factory-built 904/6.

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