Corvair Fuel Pump Replacement: A Step-By-Step Guide

Replacing the fuel pump on a Corvair is a complex task that requires careful consideration of several factors. The first decision to make is whether to stick with the stock mechanical fuel pump or switch to an electric fuel pump. While mechanical fuel pumps are reliable and have been widely tested in Corvairs, they have been known to fail and cause issues such as fuel leaks. Electric fuel pumps, on the other hand, are generally more reliable and can help prevent vapor lock, but they require additional safety features such as a shut-off switch in case of accidents.

The next step is to source the appropriate parts. For a mechanical fuel pump, one must ensure that the pump has a reinforced fabric construction and the correct output pressure to avoid overwhelming the carburetor inlet needles. For an electric fuel pump, it is essential to choose a low-pressure model and consider adding a fuel filter to protect the pump from contaminated fuel.

Finally, the installation process varies depending on the type of fuel pump chosen. Mechanical fuel pumps require careful seating and installation, while electric fuel pumps should be mounted close to the fuel tank or in a cool and protected area, with consideration given to fuel lines and safety wiring.

Electric Fuel Pump Conversion Kits

The Basic Kit includes an electric pump and filter, installation kit, and oil pressure safety switch. The Ultimate Kit includes the same, plus both the inertia and oil pressure style safety switches.

The electric fuel pumps are top quality, 100% solid state, and the quietest pump on the market. They last longer than regular pumps, are much less affected by vapour lock, and are water-tight and corrosion-resistant. They also have built-in pressure relief for less chance of flooding.

It is recommended to add a safety switch so that it stops the pump if the engine "dies". The oil pressure style has been used for years and shuts off the power to the pump if the oil pressure drops (engine stops). The inertia switch will shut off the power to the pump if it senses an abrupt stop (as in an accident). However, the inertia switch has a drawback. If the engine stalls while left running, the pump can keep running and flood the engine with fuel. The best option is to install one of each type in series, so either one can shut off the pump depending on the situation.

Additionally, there is a fuel pump by-pass plate that replaces the centre of the fuel pump when using an electric pump. This ensures the fuel goes straight through, won't leak, and looks very close to stock.

When considering an electric fuel pump conversion, it is important to note that the electric pump should be installed near the fuel tank, as they do a better job of pushing the fuel long distances. It is also recommended to use a fuel distribution block and high-quality fuel lines to help keep the engine compartment safe from a potential leak and fire hazard.

Some electric fuel pump options include the Airtex E8251 Universal Solid State Electric Fuel Pump for Marine Applications and the Facet pump.

Rebuilding a Corvair fuel pump

To rebuild a Corvair fuel pump, you will need to source a rebuild kit. These are not always readily available, and the quality can vary. If you are unable to find a kit, you may need to purchase a new fuel pump.

If you are successful in finding a rebuild kit, ensure you have the necessary tools and a suitable workspace before beginning the rebuild. Follow these steps:

• Remove the old fuel pump from your Corvair, being careful not to damage any surrounding components or leak fuel.
• Completely disassemble the fuel pump, taking care to keep all parts organised and accounted for.
• Clean all parts thoroughly, removing any dirt, grease, or debris. Inspect for any signs of damage, such as cracks or excessive wear. Replace any damaged parts.
• Refer to the instructions provided with your rebuild kit to reassemble the fuel pump, ensuring all new components are installed correctly.
• Once reassembled, test the fuel pump to ensure it is functioning correctly and there are no leaks.

Please note that this is a general guide, and specific steps may vary depending on the model of your Corvair and the type of fuel pump it uses. Always refer to the manufacturer's instructions or seek advice from a qualified mechanic if you are unsure.

Additionally, consider the benefits of converting to an electric fuel pump. While some prefer to stay with the stock mechanical pump, electric pumps can offer advantages such as longer life, reduced impact of vapor lock, and less chance of flooding. They also eliminate the need for complex rebuilds, as replacement is typically more straightforward.

Mechanical vs. electric fuel pumps

Overview

When it comes to fuel pumps, there is no one-size-fits-all solution. The decision between a mechanical and an electric fuel pump depends on various factors, including operational and cost benefits. Both types of fuel pumps have their advantages and disadvantages, and it is essential to consider these when deciding which type of fuel pump is most suitable for your vehicle.

Mechanical Fuel Pumps

Mechanical fuel pumps are the standard type of fuel pump that has been used for many years. They work by using a piston to push fuel from the tank to the engine and are connected to the engine with a belt. This type of pump is generally quieter and tends to be more durable, making it suitable for vehicles operating in harsh conditions.

Benefits of Mechanical Fuel Pumps:

• Lower cost: Mechanical fuel pumps are typically less expensive than electric fuel pumps.
• Ease of repair: They have fewer parts and a simpler design, making them easier to repair.
• Durability: They are more durable, especially in extreme temperatures and conditions.

Drawbacks of Mechanical Fuel Pumps:

• Lower efficiency: Mechanical fuel pumps may not be as efficient as electric fuel pumps and may struggle to meet the demands of a high-performance engine.
• More prone to failure: They have more moving parts, which can lead to wear and tear and potential breakdowns over time.
• Difficult installation: They can be more complicated to install due to their additional parts and complex design.
• Higher maintenance: They require more frequent maintenance and upkeep than electric fuel pumps.

Electric Fuel Pumps

Electric fuel pumps are a more modern type of fuel pump that has gained popularity due to their efficiency and performance. They use an electric motor to push fuel from the storage tank to the engine and are usually located inside or very close to the tank.

Benefits of Electric Fuel Pumps:

• Efficient fuel delivery: They provide a consistent and steady flow of fuel to the engine, resulting in improved vehicle performance.
• Easier installation: They are generally easier to install compared to mechanical fuel pumps.
• Faster start times: They can provide fuel to the engine more quickly, resulting in faster start-up times for your vehicle.
• Reduced maintenance: They require less maintenance and have a longer lifespan than mechanical fuel pumps, reducing overall maintenance costs.
• Reliability: They are more reliable and less likely to fail due to wear and tear.
• Lower emissions: They help reduce emissions by burning fuel more efficiently.

Drawbacks of Electric Fuel Pumps:

• Higher cost: Electric fuel pumps tend to be more expensive than mechanical fuel pumps.
• Complexity: They have more moving parts and require a complex setup, making installation and troubleshooting more difficult.
• Inadequate cooling: They operate at higher temperatures and require additional cooling to prevent overheating and potential engine damage.
• Increased power requirements: They demand more power, which may necessitate additional components in your vehicle.
• Heat generation: They tend to generate more heat, which can be problematic in hot climates.

In conclusion, both mechanical and electric fuel pumps have their advantages and disadvantages. Mechanical fuel pumps offer cost-effectiveness, ease of repair, and durability, while electric fuel pumps provide improved efficiency, performance, and reliability. The decision between the two ultimately depends on your specific needs, vehicle type, and budget. Consulting a professional mechanic or auto parts specialist can help you make an informed choice that best suits your requirements.

Fuel pump pressure

There are two types of fuel pumps: mechanical and electric. Mechanical fuel pumps have been standard in Corvairs since their introduction, while electric fuel pumps are more common in modern cars. Mechanical pumps use a diaphragm and pushrod mechanism to create suction and draw fuel from the tank, while electric pumps use an electric motor to pressurize the fuel and deliver it to the engine.

When replacing the fuel pump in your Corvair, you have the option of choosing between a mechanical or electric pump. Each type has its own advantages and considerations regarding fuel pump pressure:

Mechanical Fuel Pumps:

• Mechanical pumps are simple and reliable, having been widely tested in Corvairs for decades.
• They are easy to remove and replace, making roadside repairs convenient.
• However, mechanical pumps have been known to fail, causing fuel leaks and, in rare cases, flooding the engine with fuel.
• To ensure optimal performance and prevent issues, it is crucial to properly seat and install the pump, following the instructions and specifications in the Corvair shop manual.
• Rebuild kits for mechanical fuel pumps are generally not recommended due to varying quality and the availability of reliable new pumps.

Electric Fuel Pumps:

• Electric fuel pumps offer a modern alternative and are generally reliable.
• They can provide higher fuel pressure, which may be beneficial for certain carburetor types.
• Electric pumps require safety interlocks, such as an oil pressure safety switch or an inertia-type shut-off switch, to prevent fuel leaks and potential flooding.
• The conversion to an electric pump may be more complex and costly, requiring changes to the plumbing and wiring.
• It is important to note that the incoming fuel line system in Corvairs was not designed to be pressurized, so special considerations are necessary when converting to an electric pump.

In conclusion, when replacing the fuel pump in your Corvair, it is essential to consider fuel pump pressure and the associated advantages and challenges of both mechanical and electric pumps. Proper installation, safety measures, and maintaining correct fuel pressure are crucial for optimal performance and fuel efficiency.

Fuel pump safety

Fuel pumps are an essential component of a car's operation, transferring fuel from the gas tank to the engine. They are durable but not indestructible, and you may need to replace yours at some point. Here are some safety precautions to take when replacing a fuel pump:

Preparation

Before starting, it's important to gather all the necessary tools and components, including a new fuel pump, fuel filter, and any other parts specific to your vehicle. Reducing the amount of fuel in the tank is also advisable, as it lowers the risk of spillage and makes the tank easier to handle. In addition, ensure you have a safe and accessible workspace, and don't forget to pull the fuel pump relay and disconnect the battery.

Work Environment

Fuel vapours are highly flammable and toxic, so work in a well-ventilated area, preferably outdoors, to minimise the risk of fire or inhalation of harmful fumes. Always wear safety gear, including glasses, gloves, and appropriate clothing, to protect yourself from fuel spills and splashes.

Fuel Pump Components

When replacing the fuel pump, consider replacing related components, such as the fuel filter, fuel pump strainer, and fuel tank O-ring or gasket. This can help prevent future issues and ensure the fuel system functions optimally.

Safety Switches

If you're installing an electric fuel pump, it's crucial to include safety switches. The oil pressure safety switch shuts off power to the pump if the oil pressure drops or the engine stops, preventing the engine from flooding. Additionally, consider an inertia-type safety switch, which will shut off power to the pump if it senses an abrupt stop, such as in an accident. Installing one of each type ensures that either switch can shut off the pump depending on the situation.

Fuel Line Connections

Before removing the old pump, take note of the fuel line connections and wiring. When installing the new pump, ensure it is correctly seated and installed. There should be a tapered hole in the side of the pump shaft that the tapered bolt tip must seat into. If the pump is sitting too high, the bolt will press against the side of the housing instead, and the pump pushrod will not function properly.

Frequently asked questions