question: Why do diesel engines seem to outlast gasoline engines? Shouldn't they be built with the same stress safety factors built in and fail at around the same rate?
comment: Gasoline engines usually operate at 25-50% higher RPM and have longer piston strokes further increasing piston speed which causes increased wear on pistons and cylinders as well as stress on the connecting rods. Both rods and pistons also have to be lighter to accommodate the higher speed. Diesel engines on the other hand have to be built stronger to allow higher compression ratios that can auto-ignite the fuel. That being said I doubt you will see very significant differences in lifespans of modern engines that are properly maintained. Maintenance is probably the biggest factor that increases lifespan of commercial vehicles that have to regularly undergo it while passenger vehicles don't necessarily do so. And this is probably where the greater robustness of diesel engines might allow them to better cope with lousy maintenance.
passages: Fuel and oil leaks causing an engine runaway can have both internal and external causes. Broken sealings or a broken turbocharger may result in high amounts of oil mist entering the inlet manifold, whereas defective injection pumps may result in unintentionally high amounts of fuel being injected directly into the combustion chamber. If a diesel engine is operated in an environment where combustible gasses are used, a gas leak may result in an engine runaway if the gas can enter the engine's inlet manifold.
  
  Section::::Stopping a runaway engine.
   Diesel engines can combust a huge variety of fuels, including many sorts of oil, petrol, and combustible gasses. This means that if there is any type of leak or malfunction resulting in high amounts of oil or fuel unintentionally entering the combustion chamber, the quality of the air-fuel-mixture increases, causing the engine to produce a high amount of torque and having a very high rotational frequency at the same time.
   Section::::Causes and special cases.:Diesel engines.
  
  Diesel engines are more susceptible to hydrolock than gasoline engines. Due to their higher compression ratios, diesel engines have a much smaller final combustion chamber volume, requiring much less liquid to hydrolock. Diesel engines also tend to have higher torque, rotating inertia, and stronger starter motors than gasoline engines. The result is that a diesel engine is more likely to suffer catastrophic damage.
  
  Section::::Causes and special cases.:Radial and inverted engines.
   Many manufacturers have adopted statistical process control (SPC) as a method of measuring the integrity of fuel tanks. Typically, using SPC, the manufacturer will test samples from a production lot and draw conclusions from the statistical data. However some manufacturers strive for a zero-failure rate and test each tank as part of their quality program.
   Section::::Notable incidents involving diesel engine runaway.
  
  In the Texas City Refinery explosion, an instance of diesel engine runaway is thought to have provided the ignition source that triggered the massive explosion. After the refinery's blowdown stack failed and started releasing raffinate into the air, a pickup truck that had been parked near the blowdown stack with its engine idling was engulfed by the vapor cloud released and the engine began to race. As staff at the refinery attempted to stop the truck's now-overheating engine, it backfired, igniting the vapor cloud and triggering the disaster.
  
  Section::::See also.
  
  BULLET::::- Rev limiter
   The viscosity requirement of diesel fuel is usually specified at 40 °C. A disadvantage of diesel as a vehicle fuel in cold climates is that its viscosity increases as the temperature decreases, changing it into a gel (see Compression Ignition – Gelling) that cannot flow in fuel systems. Special low-temperature diesel contains additives to keep it liquid at lower temperatures, but starting a diesel engine in very cold weather may still pose considerable difficulties. Another disadvantage of diesel engines compared to petrol/gasoline engines is the possibility of diesel engine runaway failure. Since diesel engines do not need spark ignition, they can run as long as diesel fuel is supplied. Fuel is typically supplied via a fuel pump. If the pump breaks down in an open position, the supply of fuel will be unrestricted, and the engine will run away and risk terminal failure.
   BULLET::::- Diesel engines can accept super- or turbocharging pressure without any natural limit, constrained only by the design and operating limits of engine components, such as pressure, speed and load. This is unlike petrol engines, which inevitably suffer detonation at higher pressure if engine tuning and/or fuel octane adjustments are not made to compensate.
  
  Section::::Fuel injection.
   Section::::Causes of infeasibility.
   Formerly, gasoline/petrol engines exhibited better throttle response than diesel engines. This results from higher specific power output and higher maximum engine power, as well as the fact that lower-powered diesel engines were disproportionately heavier. Recently diesel engines became able to outperform similar-sized petrol engines. Most naturally aspirated gasoline engines have better responsiveness than supercharged or turbocharged engines for engines with similar peak power outputs. However, factors such as improper maintenance, fouled spark plugs or bad injectors can reduce throttle response. Diesel engines are less likely to lose throttle response, since their power comes from self-igniting fuel. Older diesel engines directly connect the accelerator pedal to the injection pump resulting in instant response.
   The diesel engine of the V 300 had significant initial problems; the original crankshaft was made from ductile cast iron but was prone to cracking, particularly after the winter. The cast cranks were replaced with forged versions providing running for 20,000 hours, but initially they suffered from low surface hardness; this problem was solved by nitriding the surface, and by locally heating the surface with a CO laser (see annealing).
   Section::::Origins.:Diesel engines.
  
  Owing to their high compression ratios and their high bmep, diesel engines place a high tensile stress on their cylinder block. Light alloy cylinder blocks have their usual weight advantages, but these must also withstand the high forces. Some designs, such as the US Hercules, achieve this by using long through bolts. In the Hercules design these are long studs with a nut at both top and bottom; they are prevented from rotating by an eccentric collar in the middle.
  
  Section::::Origins.:Cars.
   Section::::Safety.
  
  Section::::Safety.:Fuel flammability.
  
  Diesel fuel is less flammable than petrol, because its flash point is 55 °C, leading to a lower risk of fire caused by fuel in a vehicle equipped with a diesel engine.
  
  Diesel fuel can create an explosive air/vapour mix under the right conditions. However, compared with petrol, it is less prone due to its lower vapour pressure, which is an indication of evaporation rate. The Material Safety Data Sheet for ultra-low sulfur diesel fuel indicates a vapour explosion hazard for diesel fuel indoors, outdoors, or in sewers.
  
  Section::::Safety.:Cancer.
   In fact, a consist of such units can produce more than enough drawbar pull at start-up to damage or derail cars (if on a curve) or break couplers (the latter being referred to in North American railroad slang as "jerking a lung"). Therefore, it is incumbent upon the engine driver to carefully monitor the amount of power being applied at start-up to avoid damage. In particular, "jerking a lung" could be a calamitous matter if it were to occur on an ascending grade, except that the safety inherent in the correct operation of automatic train brakes installed in wagons today, prevents runaway trains by automatically applying the wagon brakes when train line air pressure drops.
   Continental Motors reports the FAA states general aviation engines experience one failures or IFSD every 10,000 flight hours, and states its Centurion engines is one per flight hours, lowering to one per flight hours in 2013-2014.
  
  The General Electric GE90 has an in-flight shutdown rate (IFSD) of one per million engine flight-hours.
  
  The Pratt & Whitney Canada PT6 is known for its reliability with an in-flight shutdown rate of one per hours from 1963 to 2016, lowering to one per hours over 12 months in 2016.
  
  Section::::Reliability.:Emergency landing.
   Another source of high engine friction is the valve train. Hydraulic lash adjusters (HLAs) are always in contact with the valves. The hydraulic pressure of the lash adjuster must be overcome during operation and during the most critical time of engine start.
   FAME as a fuel is specified in DIN EN 14214 and ASTM D6751.
  
  Fuel equipment manufacturers (FIE) have raised several concerns regarding FAME fuels, identifying FAME as being the cause of the following problems: corrosion of fuel injection components, low-pressure fuel system blockage, increased dilution and polymerization of engine sump oil, pump seizures due to high fuel viscosity at low temperature, increased injection pressure, elastomeric seal failures and fuel injector spray blockage. Pure biodiesel has an energy content about 5–10% lower than petroleum diesel. The loss in power when using pure biodiesel is 5–7%.
   The higher compression ratio in diesels means they are harder to start, but once they are running the energy expended in compressing air is regained during the expansion stroke when the compressed air is allowed to "spring" back, so the higher compression ratio causes negligible engine braking via energy being lost as friction and heat of compressed air to engine block.
  
  Section::::Type.:Diesel engines.:Compression release brake.
   Diesel engine runaway
  
  Diesel engine runaway is a rare condition affecting diesel engines, in which the engine draws extra fuel from an unintended source and overspeeds at higher and higher RPM and producing up to 10 times the engine's rated output until destroyed by mechanical failure or bearing seizure through lack of lubrication.
  
  Section::::Causes.
   Since diesel engines operate on the principle of compression ignition, a fuel which resists autoignition will cause late ignition, which can lead to engine knock. Diesel engines have a higher peak combustion temperature than petrol engines, but the greater expansion means they reject less heat in their cooler exhaust. 
  
  Section::::Effect and typical ratios.:Other fuels.
  
  The compression ratio may be higher in engines running exclusively on LPG (Autogas) or compressed natural gas, due to the higher octane rating of these fuels.
   In a diesel engine, the torque (and the rotational frequency) are controlled by means of "quality torque manipulation". This means, that with each intake stroke, the engine sucks in air that is not mixed with fuel. The fuel is injected into the air "after" it has been compressed in the compression stroke, and due to the high air temperature, the fuel then combusts. The amount of torque the engine produces is manipulated by altering the injected fuel mass only; the more fuel injected, the higher the torque produced. Altering the amount of fuel solely alters the quality of the air-fuel-mixture, and altering the amount of the mixture itself is not required, which is why diesel engines do not need throttle valves.
   A secondary problem with either the 3.5L (though true for any of the OM60x family diesels) is lack of maintenance of the motor mounts, which results in hard engine vibration from the engine resting on the frame members. Especially in the OM603, the vibration helps loosen one of the myriad of small screws in the crankcase which primarily hold on the windage tray. If these small bolts and screws find their way into the oil pump or passages, the resulting oil starvation can cause bearing failure, and subsequent broken or thrown rods—often cracking the block. Proper motor mount maintenance eliminates these issues.
   Production gaskets will let go under these conditions every time, just like the example shown. It is important to note here that no engine should ever be run under these adverse conditions purposely, however during the ‘tuning’ period of many performance engines these severe conditions may be encountered for short periods, so it is vital to have a cylinder head gasket that can withstand brief bursts of detonation without letting go, so that further adjustments can be made to “tune out” any detonation spikes.
   The "3E" and "3E-E" engines are considered slightly less reliable than other Toyota engines, although they are also among the easiest engines to service. The most common problems affecting these engines are premature valve stem seal (nitrile rubber) failure, carbon buildup on the intake valves, and collapse of the oil control ring on the piston. Any of these conditions can lead to rough idling, stalling, and fouled spark plugs, and therefore need to be differentially diagnosed. The valve stem seals, at least, can be replaced with silicone or Viton-based seals which last much longer.
  
  Section::::4E.
   These types of contamination can be introduced from many different sources throughout the supply chain of the diesel fuel as well as within the storage tank itself. Any one of these contaminants can cause complete engine failure.
  
  In April 2010, Cathay Pacific Flight 780, an aircraft carrying over 300 passengers, had a close call when fuel contaminated with spherical particles damaged the aircraft's engines, resulting in 57 passenger injuries as the pilots had to land the aircraft at twice the normal landing speed.
  
  Section::::Symptoms of 'diesel bugs'.
   Model diesels are found to produce more torque than glow engines of the same displacement, and are thought to get better fuel efficiency, because the same power is produced at a lower rpm, and in a smaller displacement engine. However, the specific power may not be significantly superior to a glow engine, due to the heavier construction needed to assure that the engine can withstand the much higher compression ratio, sometimes reaching 30:1. Diesels also run significantly quieter, due to the more rapid combustion, unlike two-stroke glow engines, in which combustion may still be occurring when the exhaust ports are uncovered, causing a significant amount of noise.
  
presuppositions: Diesel engines and gasoline engines work the same. There is not a valid reason as to why diesel and gasoline engines are not built similarly. 
corrections: Diesel engines and gasoline engines work differently and are unable to be built the same.  Diesel engines have to be built stronger or else they would not be able to auto ignite their fuel. 
raw_presuppositions: Diesel engines and gasoline engines work the same. There is not a valid reason as to why diesel and gasoline engines are not built similarly.  They should be built with the same stress safety factor.
raw_corrections: Diesel engines and gasoline engines work differently and are unable to be built the same.  Diesel engines have to be built stronger or else they would not be able to auto ignite their fuel.  Diesel engines have to be built stronger.