Fuel Cell Maintenance: Bladder And Foam Replacement Guide

Safety fuel cells are an important piece of safety equipment in racing cars. They are designed to prevent fuel spillage in the event of a crash. Fuel cells generally consist of three parts: the outer can or enclosure, the bladder, and the foam baffling. The bladder is the flexible, fuel container that prevents spillage, and the foam baffling helps to prevent fuel sloshing and also prevents flash-back explosions. Due to the dangerous nature of fuel, it is important to know when to replace these components. Flexible fuel bladders typically last 5-10 years, whereas rigid bladders can last the entirety of a vehicle's useful life. However, fuel cells have a finite lifespan and are only certified for 5 years from the date of manufacture, with the option to recertify for an additional 2 years. Therefore, it is recommended to replace the bladder at least every 5 years, and to inspect and replace the foam baffling annually or biennially, depending on the type of fuel used.

Bladder inspection and replacement

Inspection

Before inspecting the bladder, ensure you take the necessary safety precautions as the fuel cell contains flammable liquids. It is recommended to drain the fuel cell and fill it with water for safety.

The bladder should be inspected annually and after any accidents. Check the bladder for any gashes, cuts, or wear. Look for any markings that indicate it has expired. The typical lifespan of a fuel cell is between 8 and 10 years, but most sanctioning bodies limit their use to 5 years from the manufacturing date.

Inspect the interior and exterior of the fuel cell for any debris or rough edges that could damage the bladder. Check for signs of delamination, where the elastomer coating separates from the aramid fabric, and cracking in the elastomer coating. Pay close attention to folded edges and areas around moulded necks or spouts as cracks often appear in these areas.

Replacement

If you find any issues during inspection, it is best to replace the bladder. Replacement bladders are available for purchase, and they typically include a new bladder, 5 years of FIA-FT3 certification (if applicable), and an internal fuel pickup hose.

The process of replacing the bladder involves removing the fuel cell from the car and disassembling it. This includes removing the plate at the bottom where the fuel lines connect and the filler plate. Then, remove the large plate on top of the fuel cell container to access the bladder.

When installing a new bladder, protect the edges and bottom surface with a protective tape like Leading Edge Tape to prevent chafing. Ensure that the bladder and container are completely dry before assembly. Refer to the manufacturer's instructions for specific details.

Maintenance

To prolong the life of your bladder, it is essential to properly maintain the fuel cell. Avoid fuel additives, and do not store fuel in the cell for extended periods. Avoid exposing the cell to harsh chemicals and solvents. Store your bladder in a cool, dry place, away from direct sunlight.

Additionally, consider the type of fuel you are using. If using alcohol-bearing fuel, drain the cell immediately after each event as alcohol attacks the foam baffling. With pure hydrocarbon gasoline, replace the foam baffling periodically; annually for racing gas or AvGas, and every two years for pure petroleum fuel.

Foam inspection and replacement

The foam baffling inside a fuel cell is a crucial safety feature that should not be overlooked. While it may be tempting to skip the inspection or delay replacement, doing so could compromise your safety in the event of an accident. Here are some detailed guidelines to help you inspect and replace the foam in your fuel cell effectively:

Inspection Techniques:

• Pinch-Pull Test: Take a small piece of the foam and use your thumb and index finger to pinch and pull it. If the foam is brittle and breaks into large pieces, it needs to be replaced. However, if it sheds only small particles, this is normal and does not require immediate replacement.
• Visual Inspection: Check the foam for any signs of degradation, such as discolouration, cracks, or tears. Pay close attention to the areas where the foam comes into contact with the bladder, as this is where wear and tear are most likely to occur.
• Fuel Filter Inspection: Cut open your fuel filter and inspect it for debris or foam particles. If you find a significant amount of foam in the filter, it's a clear indication that your fuel cell foam needs to be replaced.

Replacement Guidelines:

• Replacement Interval: Fuel cell foam typically lasts around five years if properly maintained. However, it is recommended to inspect your foam at least once a year for the first three years, then twice a year for the next two years, and more frequently in the following years.
• Fuel Type Considerations: The longevity of the foam also depends on the type of fuel used. If you use alcohol-bearing gasoline or fuels with high alcohol content, such as E85, you must drain the cell after each event as alcohol attacks the foam baffling.
• Compatibility: Ensure that you purchase foam compatible with the type of fuel you are using. For example, if using methanol (alcohol) engines, opt for foam designed for methanol, such as ATL's SF110 foam.
• Storage: When storing your foam, wrap it in a clean trash bag and keep it in a dry, dark, and warm place. Avoid exposure to harsh chemicals, solvents, or direct sunlight, as these can accelerate degradation.

By following these guidelines and performing regular inspections, you can help ensure your safety and maintain the performance of your vehicle. Remember, your fuel cell foam plays a crucial role in absorbing impact energy and preventing fuel spills during accidents, so never neglect its maintenance.

Fuel cell maintenance

Safety fuel cells are an essential piece of safety equipment in most forms of racing. They are designed to prevent spilled fuel in the event of a crash.

A fuel cell typically consists of three parts: the outer can or enclosure, the bladder, and the foam baffling. The bladder is the flexible, extremely strong, fuel container that prevents fuel spillage in an accident. The foam baffling inside the bladder has several functions: it prevents the fuel from sloshing around, keeps the fuel de-aerated to improve delivery, and prevents flashback explosions.

It is important to maintain and regularly inspect your fuel cell. Here are some guidelines for fuel cell maintenance:

• Fuel cells have a finite lifespan, typically between 8 and 10 years, but sanctioning bodies limit their use to 5 years from the date of manufacture.
• Avoid fuel additives and do not store fuel in the cell for long periods.
• Do not expose the cell to harsh chemicals or solvents.
• Store your bladder in a cool, dry place, out of direct sunlight.
• Inspect the interior and exterior of your cell at least once a year.
• Torque fill plate bolts to the recommended tension.

When inspecting your fuel cell, here are some things to look out for:

• Check the bladder for any gashes, tears, or wear marks.
• Ensure the markings on the bladder show that it is not expired.
• Check the gasket between the fuel bladder and the fill plate for any cuts or gashes.
• Inspect the fuel fill plate to ensure that the spring that controls the fluid entering the overflow tube is working properly.
• Check the fuel pickup to ensure the valve is opening and closing with ease.
• Inspect the fuel line for any abrasions or pinches and ensure it is made of steel-braided material.
• Check the condition of your fuel filter and replace it regularly.

If you find any issues during your inspection, it is important to address them promptly. Replacing the bladder and foam in a fuel cell can be a simple job, but it can be very dangerous if not done properly, as fuel is highly explosive. Always take the necessary precautions when working with fuel cells.

Fuel cell lifespan

Fuel cells have a finite lifespan, which is typically between 8 and 10 years. However, it's important to note that this lifespan can vary depending on the product line of the bladder and the elements it is exposed to. For example, flexible fuel bladders usually last 5 to 10 years, while rigid or hard-sided fuel bladders can last the entire vehicle's useful life. Additionally, all sanctioning bodies limit the use of fuel cells to 5 years from the date of manufacture, with the option to recertify for an additional 2 years, resulting in a total maximum lifespan of 7 years.

To ensure the safety and performance of your vehicle, it is crucial to inspect and maintain your fuel cell regularly. This includes avoiding fuel additives, not storing fuel in the cell for extended periods, avoiding exposure to harsh chemicals and solvents, and storing your bladder in a cool, dry place away from direct sunlight. It is also recommended to inspect the interior and exterior of your cell annually.

The bladder, being the core of the system, plays a vital role in preventing fuel spillage during accidents. It is made from high-tensile-strength elastomeric components designed to withstand fuel chemical attacks. Over time, the bladder can become hard and cracked, leading to leaks. Therefore, it is essential to replace the bladder when necessary to maintain the safety of your vehicle.

The foam baffling inside the bladder serves multiple functions, including displacing a small amount of fuel, preventing fuel sloshing, improving fuel delivery, and preventing flashback explosions. It also provides additional protection by holding the bladder in shape. However, the foam baffling may need to be replaced periodically, especially if it is degraded or broken into large portions.

In conclusion, the lifespan of a fuel cell is influenced by various factors, and regular maintenance and inspections are crucial to ensure the optimal performance and safety of your vehicle. By following the recommended guidelines and replacing the bladder and foam as needed, you can maximise the lifespan of your fuel cell and maintain its functionality and protective capabilities.

Fuel cell installation

When installing a fuel cell, it is important to remember that it is a vital piece of safety equipment. A fuel cell consists of three main parts: the outer can or enclosure, the bladder, and the foam baffling.

Installation Steps:

• Inspect the inside of the enclosure for any debris or rough edges that could damage the cell. Smooth out any rough edges and clean the inside of the container to minimize the possibility of damage to the bladder.
• Ensure that the bladder and container are completely dry before assembling.
• Consider using a protective tape, such as Leading Edge Tape, along the edges and bottom surface of the bladder to protect against chafing.
• Read and save the manufacturer's instructions. These will include important information such as the FIA hologram on the bladder and the certificate stating that your new cell meets the applicable FIA standard. This certificate should be brought to the car's first tech inspection and any annual tech inspections.
• When installing the bladder, use baby powder on the outside of the bladder and on the inside of the aluminium cell for easier installation.
• If you are using a fuel pickup that has a swing-door valve, ensure that the valve is opening and closing with ease.
• Check the fuel line for any abrasions or pinches. Steel-braided lines are recommended for safety.
• Ensure the fill plate can fasten to the fuel bladder without any resistance.

Maintenance and Storage:

• Drain the cell completely before off-season storage.
• If using an alcohol-bearing fuel, drain the cell immediately after every event as alcohol attacks the foam baffling.
• Gasoline exposure also affects the bladder, so replace the foam baffling periodically. Annual replacement is not necessary with racing gas or AvGas; every two years is usually sufficient.
• Store the bladder in a cool, dry place, out of direct sunlight. For rubber bladders, store in a dry, dark, and warm place as they are vulnerable to damage from cold winters.

Inspection:

• Inspect the bladder for any gashes, tears, or wear marks, especially after an accident.
• Check the markings on the bladder to ensure it hasn't expired. Fuel cells typically have a lifespan of 5-10 years, but most sanctioning bodies limit their use to 5 years from the date of manufacture.
• Look for signs of delamination (the elastomer coating separating from the aramid fabric) and cracking in the elastomer coating. Cracks may appear as dark areas where fuel and other contaminants have soaked into the inner fabric, or along folded edges and around the base of molded necks or spouts.
• If you are using a methanol or gasoline engine, replace the fuel filter during the teardown.

Remember, safety should always be the top priority when working with fuel cells. Always use line caps to cap off your fuel line when disconnected, and drain the fuel cell before removing it from the vehicle.

Frequently asked questions