Post by me on May 12, 2017 11:51:40 GMT
FOUND THIS ARTICLE ON MODERN PETROL - HAVE A READ -
The first major change was the removal of lead from the gasoline. The next major change was to reformulate the gasoline to reduce both the evaporative and exhaust emissions from vehicles. Then, the federal government mandated the use of oxygenation of gasoline in many parts of the county.
The latest method to oxygenate the fuel is with ethanol made from corn.
These recent changes in gasoline formulation may or may not be a good idea in theory, but since this modern gasoline contains less energy than it did in the past it may actually cause a loss in power, fuel efficiency and driveability unless the engine is properly tuned for these new blends of gasoline.
Gasoline with Ethanol
The addition of ethanol to the gasoline is causing problems with many fuel system components of in a vehicle’s fuel system that was not designed with ethanol in mind. Ethanol is very corrosive to many of the materials that were commonly used in fuel system of older vehicles.
Ethanol can also act as a solvent that will attack any component made with plastic or rubber compounds (such as the fuel hoses) that it comes into contact with, also components made from brass, copper and aluminum can become corroded over time if they are not given proper surface treatments.
Heat is also a factor to consider in how quickly the rubber and plastic compounds used in the fuel system will degrade with the exposure to the fuel because the rate of reaction doubles for every 10°C rise in temperature.
Ethanol is also a hygroscopic substance that readily attracts water from its surroundings such as the moisture that is in the air in the fuel tank, it takes as little as one tablespoon of water per gallon of gasoline to cause the ethanol to phase separate from the gasoline.
When the ethanol and water mixture phase separates from the gasoline it will drop to the bottom of the fuel tank.
This phase separated ethanol and water mixture is extremely corrosive to anything it comes into contact with. Plus, it will also cause engine performance/drivability problems as it flows into the engine through the carburetor or fuel injectors.
The ethanol content of gasoline will cause the air/fuel mixture of a non-computer controlled carburetor engine to shift leaner, which will often cause a loss in driveability and throttle response. These new blends of reformulated gasoline (with and without ethanol) are actually quite different from the leaded gasoline that a vintage carburetor equipped engine was designed and tuned to use.
The main differences between today’s gasoline and the leaded gasoline of days past are the burn time of the fuel and the distillation profile of the fuel, but it actually goes deeper than that. The composition of today’s gasoline is very different when compared to the leaded gasoline of the ’60s because of the removal of lead, the addition of ethanol and the modern fuel additives that are in the fuel.
Tuning a Vintage Engine for Modern Gasoline
It’s important to understand that the modern, fuel-injected, computer-controlled engine is a very different animal than the carbureted engines of years past. The computer of a modern, fuel-injected engine continually adjusts fuel and spark to adapt the engine to today’s ethanol and reformulated gasoline blends.
A vintage carburetor equipped engine simply cannot do this by itself, therefore you will have to retune the carburetor and distributor for these new blends of gasoline. If your customer is experiencing driveability and throttle response issues with a vintage carburetor-equipped engine the problem may be caused by the changes in today’s reformulated gasoline with the cure being to tune the ignition spark advance and air/fuel curves for the modern fuel blends of today.
The last thing any engine builder wants to have happen is to have the engine they just built have any problems caused by bad gasoline.
Whenever gasoline is exposed to heat, moisture, air or light it will begin to go bad, as the gasoline ages the most highly volatile components in gasoline tend to evaporate out through any vent in the tank. It will also degrade with time and exposure to the elements.
As the gasoline ages, it will become less volatile, which will cause the engine to be hard to start plus it will also cause the engine to produce less power. The use of this degraded fuel may be one of the worst things to which you could expose an engine that you just rebuilt to.
When gasoline is stored for an extended period of time, it will gradually turn into a varnish-like substance that if used, will raise havoc with both a fuel-injected or carburetor-equipped fuel system.
The gasoline tank of most modern fuel injected vehicles is sealed, thus its exposure to outside air and moisture is limited but you still have the heat issue to consider.
Most vehicles built before 1970 have vented gas tanks, therefore the fuel in these tanks will degrade at a much higher rate than a vehicle with a non-vented gas tank. This is because the fuel is exposed to the outside air that contains moisture that enters through the fuel tank’s vents and venting to atmosphere can allow some of the lighter/more volatile portions of the gasoline to escape.
The first major change was the removal of lead from the gasoline. The next major change was to reformulate the gasoline to reduce both the evaporative and exhaust emissions from vehicles. Then, the federal government mandated the use of oxygenation of gasoline in many parts of the county.
The latest method to oxygenate the fuel is with ethanol made from corn.
These recent changes in gasoline formulation may or may not be a good idea in theory, but since this modern gasoline contains less energy than it did in the past it may actually cause a loss in power, fuel efficiency and driveability unless the engine is properly tuned for these new blends of gasoline.
Gasoline with Ethanol
The addition of ethanol to the gasoline is causing problems with many fuel system components of in a vehicle’s fuel system that was not designed with ethanol in mind. Ethanol is very corrosive to many of the materials that were commonly used in fuel system of older vehicles.
Ethanol can also act as a solvent that will attack any component made with plastic or rubber compounds (such as the fuel hoses) that it comes into contact with, also components made from brass, copper and aluminum can become corroded over time if they are not given proper surface treatments.
Heat is also a factor to consider in how quickly the rubber and plastic compounds used in the fuel system will degrade with the exposure to the fuel because the rate of reaction doubles for every 10°C rise in temperature.
Ethanol is also a hygroscopic substance that readily attracts water from its surroundings such as the moisture that is in the air in the fuel tank, it takes as little as one tablespoon of water per gallon of gasoline to cause the ethanol to phase separate from the gasoline.
When the ethanol and water mixture phase separates from the gasoline it will drop to the bottom of the fuel tank.
This phase separated ethanol and water mixture is extremely corrosive to anything it comes into contact with. Plus, it will also cause engine performance/drivability problems as it flows into the engine through the carburetor or fuel injectors.
The ethanol content of gasoline will cause the air/fuel mixture of a non-computer controlled carburetor engine to shift leaner, which will often cause a loss in driveability and throttle response. These new blends of reformulated gasoline (with and without ethanol) are actually quite different from the leaded gasoline that a vintage carburetor equipped engine was designed and tuned to use.
The main differences between today’s gasoline and the leaded gasoline of days past are the burn time of the fuel and the distillation profile of the fuel, but it actually goes deeper than that. The composition of today’s gasoline is very different when compared to the leaded gasoline of the ’60s because of the removal of lead, the addition of ethanol and the modern fuel additives that are in the fuel.
Tuning a Vintage Engine for Modern Gasoline
It’s important to understand that the modern, fuel-injected, computer-controlled engine is a very different animal than the carbureted engines of years past. The computer of a modern, fuel-injected engine continually adjusts fuel and spark to adapt the engine to today’s ethanol and reformulated gasoline blends.
A vintage carburetor equipped engine simply cannot do this by itself, therefore you will have to retune the carburetor and distributor for these new blends of gasoline. If your customer is experiencing driveability and throttle response issues with a vintage carburetor-equipped engine the problem may be caused by the changes in today’s reformulated gasoline with the cure being to tune the ignition spark advance and air/fuel curves for the modern fuel blends of today.
The last thing any engine builder wants to have happen is to have the engine they just built have any problems caused by bad gasoline.
Whenever gasoline is exposed to heat, moisture, air or light it will begin to go bad, as the gasoline ages the most highly volatile components in gasoline tend to evaporate out through any vent in the tank. It will also degrade with time and exposure to the elements.
As the gasoline ages, it will become less volatile, which will cause the engine to be hard to start plus it will also cause the engine to produce less power. The use of this degraded fuel may be one of the worst things to which you could expose an engine that you just rebuilt to.
When gasoline is stored for an extended period of time, it will gradually turn into a varnish-like substance that if used, will raise havoc with both a fuel-injected or carburetor-equipped fuel system.
The gasoline tank of most modern fuel injected vehicles is sealed, thus its exposure to outside air and moisture is limited but you still have the heat issue to consider.
Most vehicles built before 1970 have vented gas tanks, therefore the fuel in these tanks will degrade at a much higher rate than a vehicle with a non-vented gas tank. This is because the fuel is exposed to the outside air that contains moisture that enters through the fuel tank’s vents and venting to atmosphere can allow some of the lighter/more volatile portions of the gasoline to escape.
