The Surprising Benefits Of Leaded Gas for Old Tractors
By Tom Seest
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Despite regular gas being discontinued since 1996, older tractors and motorized farm equipment still rely on it because these machines were not designed to run on unleaded fuel. Public health scientists engaged in a heated debate with GM and Standard Oil officials regarding the safety of tetraethyl lead, highlighting the clash between industrial progress and public health concerns. Media coverage extensively covered this issue in such terms.
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Valve seats can be an enormous source of trouble in older engines. Re-cutting or regrinding may be required and should always be performed while running and at full throttle to ensure proper contact between valve faces and seats, and for them not contacting, leading to carbon deposits build up on valve faces, which cause them to recede or even recede and swell over time. Ensuring appropriate clearances – steel feeler gauges should be used – helps avoid this problem: optimal intake clearance should range between.008″-.010″, with piston at TDC on compression stroke.
Older automotive engines feature soft cast iron valve seats, which were cut or ground directly into their cylinder heads, whereas modern cars have heat-treated steel valve seats, which last much longer due to lack of lead in fuel supply and are easier on wear and tear.
Old engines tend to suffer from improper valve seating, especially under severe conditions where dust enters the combustion chamber and wears down parts, including valve faces and seats, causing them to become worn and become “sticky”, leading to leaky head gaskets.
Depending on the age and condition of your tractor, using non-leaded gasoline with cast iron valve seats requires using lead substitute additives. But modern cars and trucks have hardened valve seats that should work fine on unleaded fuel; in these instances, your tractor should also run fine with unleaded.
To make the most out of your engine, having your valve seats recut or reground by an automotive machine shop can help optimize performance. Regrounding at either 30o or 45o angles should ensure perpendicularity between valve faces and seats and valve guides as well as narrowed width so valve stems center themselves on each new seat width.
Carburetors were once the preferred method for fuel delivery, but modern fuel injection systems now provide superior efficiency and dependability compared to them. Unfortunately, though, these systems require different fuel and spark plug specifications than carburetors do.
Attaining engine performance relies heavily on providing each cylinder with enough fuel, which is why fuel injection has replaced carburetors in modern vehicles. A fuel injector allows pressurized fuel to be delivered directly into each cylinder via a tiny nozzle atomizing each droplet so it burns more readily, then mixed with air for ignition via spark plugs.
Timing injections is also critical. A computer in your vehicle can use engine RPM measurements to assess when it is ready for starting up and sends a signal to its fuel injection system to time each injector’s pulse width, dispensing just the correct quantity at exactly the optimal point during combustion cycles.
Multiport fuel injection (MPFI) systems are the most prevalent. This system features multiple nozzles in the intake manifold that spray each cylinder’s intake valve at once with fuel/air mixture injected directly from each injector nozzle, then delivered through their respective intake valves to each cylinder in turn. While effective, this approach cannot adjust how much fuel is injected per power stroke.
Sequential fuel injection (SFI) improves on this by independently activating each injector nozzle to ensure fuel dispenses as the intake valve opens – eliminating “hang-around” issues associated with basic MPFI systems.
Though most cars now rely on fuel injection, 167,000 planes still run on leaded aviation gas or Avgas – from Cessna trainers to small commercial planes – remain leaded aviation gas users. While TEL has been banned in automotive gas, its use remains widespread in Avgas to boost octane levels; although FAA attempts have been made to encourage Avgas producers to find safe alternatives that still maintain operationally suitable levels, unfortunately, avgas sales only comprise 10% of their overall business so little incentive exists from Avgas producers; in most cases, this small percentage represents 10% or so of sales revenue.
Ethanol (ethyl alcohol) is a renewable fuel made by fermenting the sugars found in plant material to produce fuel ethanol. Used as an alternative to gasoline, it reduces dependence on fossil fuels while producing lower emissions than its gasoline equivalent. Most ethanol production comes from corn grain, while others come from wheat straw or rice stubble plants.
Not only can ethanol provide environmental advantages, it has a higher motor octane number and lower vapor pressure than gasoline, making it safer to store and transport. Furthermore, mixing E10 fuel with gasoline improves engine performance further while acting as a moisture absorber, causing components of its fuel system to rust over time – potentially leaving your vehicle sitting idle without attention for extended periods.
Classic car enthusiasts concerned about the effect of ethanol on their vehicles may opt to switch fuel types or add Redex Lead Replacement, which contains additives designed to protect systems from harmful materials such as ethanol. Some may opt to purchase E0 fuel from their local gas station – perfect for small engines found on tractors and other equipment.
Apart from maintaining engine health, using fuel without ethanol can also prevent problems with the carburetor and help to eliminate lead from the environment. Lead is toxic for humans and animals alike, poisoning spark plugs when burned as well as harming engines when burnt; since leaded gasoline was banned in 1996, it’s unlikely anyone will start producing TEL again; owners of older tractors would therefore, do well to seek an additive such as Redex Lead Replacement for their older tractors or switch fuel sources altogether.
If your old tractor features a carburetor, you might still be able to use it for light work. But you will require an additive designed specifically for its engine in order to use unleaded gasoline effectively – these additives can usually be purchased at auto parts stores and poured in when filling up. Or replace your valve seats – as John Deere engines were originally constructed from hardened metal, which reduces wear with unleaded fuel use.
Threads used to connect pipes, adapters, and fuel line components are often tapered. This threading style enables fittings to tighten themselves up naturally by the flanks of threads squeezing together without needing an o-ring seal; such threads may be made of metals such as cast iron, steel, bronze, and brass, as well as plastic materials like PTFE nylon, PVC, etc. These tapered threads are commonly known as National Pipe Taper threads, although other terms such as NPTF, NPSM, NPT, NPS, and NSP may apply depending on where their connection point falls on an assembly line.
Before connecting NPT threads, it is crucial that each surface be free from dirt and debris. A sealant (such as petroleum-based fluid, epoxy, or even Teflon tape) may also help seal off these threads from leakage. Over-tightening should also be avoided to protect their connection against potential damage or leakage issues.
When tightening a tapered-thread fitting, it must be done either by hand or wrench. This process, known as “wrench tight,” occurs at the point in which male and female thread flanks are in contact and compressing against one another to form an airtight seal between them – making for much more secure connections in high-pressure applications.
Use of suitable male and female NPT fittings is equally essential to proper fuel equipment connection. Mismatched threads will prevent proper joining, which could result in leakage under pressure. A proper seal requires threads of equal sizes – therefore, always opt for equal-sized male and female NPT fittings when connecting fuel equipment pieces together.
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