HISTORY OF DIESEL . . .
In 1892 Rudolf Diesel was issued a patent for a proposed engine that air would be compressed so much that the temperature would far exceed the ignition temperature of the fuel. Baron von Krupp and Machinenfabrik Augsburg Nurnberg Company in Germany backed Rudolf Diesel financially as well as providing engineers to work with him on the development of an engine that would burn coal dust, because there were mountains of useless coal dust piled up in the Ruhr valley. The first experimental engine was built in 1893 and used high pressure air to blast the coal dust into the combustion chamber. This engine exploded and further developments of using coal dust as a fuel failed, however a compression ignition engine that used oil as fuel was successful and a number of manufacturers were licensed to build similar engines.
The original oil burning engines used very crude mechanical injection equipment so Rudolf Diesel again began using air blast to provide atomization of the fuel as well as turbulence of the mixture. This was very successful and utilized in Rudolf Diesel's third engine built in 1895. This engine was very similar to engines being used today. It was a four-stroke cycle with 450psi compression. Progress in diesel engine development has since depended on improvements in fuel injection technology.
In 1922 Robert Bosch began the development of a fuel injection system for the diesel engine. By 1927 they finally had an acceptable injection pump. The demand for this pump was so great that Bosch in Germany was unable to keep up. In 1931 agreements were made with companies in France and England to produce injection pumps. In 1934 a company in the U.S. began manufacturing under the name of American Bosch and in 1938 the Diesel Kiki company in Japan was founded. Since then licenses have been granted to numerous manufacturing companies in several countries, most of which us Robert Bosch's designs to build injection pumps.
EVOLUTION OF INJECTION SYSTEMS . . .
Stricter emission laws are constantly forcing the automobile manufacturers to keep their engine exhaust emissions at acceptable limits, and do so has necessitated the application of some increasingly advanced electronic technology. This is true for petrol as well as diesel engines. While light and medium duty applications usually have to meet stricter emissions a few years before heavy duty and off-road, eventually all engines come under these more stringent mandates.
Through the years, the majority of light duty automotive engine manufacturers chose to utilize a mechanical injection pump with separate nozzle holder assemblies (NHA) to atomize the fuel into each cylinder. As engines began turning higher rpms, it became more difficult to maintain proper pump-to-engine timing. This resulted from a condition known as injection lag. The injection pump builds pressure, and as the delivery ports open, fuel is forced through the injection lines to the nozzle holder assembly or NHA. The length of clock time it takes to get the fuel from the injection pump to the NHA remains fairly constant throughout the speed range, but this creates a problem at higher rpms because the same amount of clock time results in a greater amount of crank angle. This of course causes a retarded timing condition.
Manufacturers of distributor style injection pumps have used an automatic speed advance device in most applications in order to start the fuel delivery from the injection pump earlier, so it will arrive at the nozzles at the proper crank angle throughout the speed range. This allowed the engine manufacturers to meet emission requirements for several years, but most automatic advance devices were hydraulically driven and totally dependent on transfer pressure generated by the injection pump itself. Pressure was controlled by pump speed, so the pump had to reach a specific speed before it could change the advance. This resulted in an imperfect, but still acceptable condition.
In 1994 the emission requirements became so strict that a fuel system's injection lag evolved into a major issue. GM, Ford (Navistar), and Dodge (Cummins) all went separate ways in order to meet the new standards. GM continued working with Stanadyne on the development of an electronic injection pump that used traditional fuel lines and nozzles. The advance device, although still hydraulically driven, is controlled by an electronic stepper motor rather than pump speed. As a result, the advance operates more accurately throughout the speed range. Since the injection pump is controlled by a computer and not directly by the operator, such things as air density, engine temperature, exhaust conditions, ambient temperature, etc. could now be monitored. The computer then controls fuel delivery so that engine exhaust emissions meet necessary legal requirements. This enabled GM to use their engine in 1/2 ton trucks as well as heavier duty applications because emission levels were under computer control.
Dodge continued to use the Cummins engine which utilized a Bosch mechanical injection pump, fuel lines, and NHAs. Bosch increased injection pressure and raised the opening pressure of the NHA so that the fuel was broken down, or atomized, into smaller droplets, thus insuring a cleaner and more complete burn. The injection pump required to generate this much peak injection pressure was a very large, expensive device. More recently, Cummins has started using an electronic Bosch injection pump on this engine. Although the Bosch pump is somewhat different from the Stanadyne injection pump, the concept of electrically controlling the injection pump remains the same. More accurate timing and fuel metering result in lower exhaust emissions.
Ford has been utilizing Navistar engines for some time and they continue to do so. The new engines, however, utilize what is known as a HEUI system. This stands for Hydraulically actuated, Electronically controlled, Unit Injection. This system uses an engine lubricating oil pump to actuate an intensifier piston in the injector. An electronically controlled solenoid opens and closes the oil passageway to the intensifier which builds injection pressure. When the solenoid is de-energized the piston is moved back to its original position by a spring. This also replenishes the fuel in the plunger chamber across a ball check valve. Fuel is supplied to the nozzle via internal passages, and as pressure increases, the nozzle lifts off of its seat and injects fuel into the combustion chamber. Injection continues until the solenoid closes and pressure drops, allowing a spring to return the nozzle valve to its seat. Utilizing this system does away with injection lines, and allows more precise fuel delivery and timing. The vehicle electronic control module (ECM) is used to store operational maps which allows it to identify the optimum rail pressure for best engine performance based on the various information fed to it by a multiple of sensors. Since this engine is a V-8, eight of these injectors are used, and replacing them can be expensive.
Virtually all of the engines now utilize a turbocharger. This allows more air to be pumped into the cylinder, and more air will allow the fuel to burn more completely. This in turn cuts down on the amount of dangerous exhaust emissions.
Most vehicle manufacturers tend to postpone change as long as possible, especially if that change is expensive. All of these changes added a major expense to the vehicle, and in some cases extra weight as well. The manufacturers will continue to face stricter emission laws, but it should be some time before another major fuel system change has to take place because of it.
DIESEL INJECTION SYSTEMS . . .
There are basically three general systems of mechanical fuel injection: the constant pressure or common rail system, the spring pressure or accumulator type, and the jerk pump.
In the common rail system fuel at a constant pressure is maintained in a manifold connected to either cam actuated nozzles or with a timing and distributor valve and pressure operated nozzles. This pressure usually from 4000 to 8000 psi, is obtained by making the fuel manifold large and utilizing the compressibility of the fuel oil, using a pump of excess capacity and delivering fuel between each injection, and by passing fuel from the accumulator through a manually or governor controlled pressure regulating valve. The amount of fuel delivered per injection is controlled by injection pressure, total nozzle orifice area, and time that the nozzle valve is lifted.
In order to keep the fuel quantity injected independent of pump speed a accumulator or spring injection was developed. The basic system used upper and lower plungers in a common bore, the lower plunger was driven by an eccentric cam and the upper plunger was spring loaded. As the bottom plunger is forced up the fuel between the plungers is pressurized based on the spring force applied to the top spring. Fuel continues to pressurize until a delivery groove in the lower plunger indexes with the outlet passage. This pressurized fuel is then injected and continues until the upper spring forces the plunger downward and closes the outlet passage.
The injection pump in the jerk pump system is used to time, meter and pressurize the fuel. This is the most common and utilized system. The plungers are driven by a camshaft that is designed to control the injection characteristics of the engine. The spray duration in crank degrees still increases with speed and fuel quantity but not to the extent of the common rail system therefore the jerk system can be used on low, medium, and high speed engines.
The jerk pump system lead to the further development of distributor style pumps, unit injectors, the "PT" fuel system, and dual fuel pumps. New systems continue to be developed. Utilization of electronics in the fuel delivery system is getting more common. Some fuel injection manufactures are developing ways for their injection pumps to charge and discharge electronically in order to keep up with current standards for the diesel engine. New systems such as the HEUI (Hydraulically actuated, Electronically controlled, Unit Injector) are currently being used on several applications in all areas especially automotive. The HEUI System develops injection pressures as high as 18-24,000 psi by applying high pressure oil to the top of an intensifier piston. Since the area of the head of this piston is 7 times the area of it’s plunger a 7:1 pressure increase on the fuel beneath the plunger is achieved. By varying the oil pressure, injection rate can be controlled independently of the crank or cam. Thus injection timing, rates, and pressures are no longer dependent on camshaft position, speed or cam ramp velocity. This is all controlled by a solenoid actuated valve that determines when high pressure oil is applied to the piston.
INTERCOOLERS . . .
What are the advantages of an intercooler?
As a turbocharger generates boost pressure the air is compressed and the temperature of the air goes up, the hotter the air gets the fewer oxygen molecules available to mix with the fuel. An intercooler allows the compressed air to cool down about 200 degrees before entering the intake manifold. This increases the amount of oxygen molecules in the engine which allows more fuel to be burned.
When is an intercooler advantageous?
Maximum turbo boost needs to be at least 15lbs. or more before an intercooler enhances the performance. If boost is less than 15 lbs. there are still enough oxygen molecules in the air to get complete combustion of the fuel.
TURBOCHARGERS . . .
How does a turbo operate?
Turbocharging is one of the less expensive ways of helping an engine generate more horsepower. A turbocharger should not be confused with a blower. Where blowers are usually belt driven and actually USE horsepower to generate boost pressure, a turbo does not take horsepower away from the engine to build boost pressure. Exhaust gas is forced through a turbine housing and drives a turbine wheel on it's way out the exhaust. The turbine wheel is attached to a shaft that rides on floating bearings and drives a compressor wheel. The compressor wheel pulls air through the air filtration system and channels it through a compressor housing, where it is compressed and directed into the engine intake manifold. The amount of "BOOST" generated by a turbo is determined by its design, which is usually determined by the engine requirements.
How does a turbo create more horsepower?
Horsepower is generated by the optimum burn of the fuel which is directly related to the fuel/air mixture. If extra air is added the fuel can be increased to bring the horsepower up. A factory turbocharged engine is designed to handle the extra fuel allowed with the added air. When installing a turbo to a non-turboed (naturally aspirated) engine, caution should be taken to assure that the system has been engineered so as not to cause engine damage.
What is a WASTEGATE and how does it work?
Since a turbo works off exhaust gas, a certain amount of exhaust pressure has to be available before boost pressure can be generated. During heavy acceleration this can cause a delay in acceleration called turbo lag. A wastegate is used to allow the turbo to develop boost pressure faster at lower RPM's. As pressure builds to the maximum pressure allowed by the engine the wastegate opens dumping exhaust gas before it reaches the turbine wheel. This keeps the turbo from overboosting at the top end.
Turbo Maintenance
A turbo can turn in excess of 100,000 RPM and since most turbos rely totally on engine oil for cooling it is necessary to keep the engine oil clean. Anytime the turbo oil lines have been drained of oil it is critical that there be oil to the turbo before starting the engine. This prevents turbo damage from lack of lubrication. Lack of lubrication damage can also occur if the oil supply to the turbo is shut off before the turbo has had time to slow down. It is normally recommended that an engine be allowed to for a few minutes before shutting off the engine. This lets the turbo slow down as well as cool before shutting off the oil supply.
YOUR FIRST DIESEL . . .
Through the years vehicle manufactures have made driving and maintaining diesel and turbo diesel vehicles as simple as possible. Such things as oil change intervals and fuel quality become more critical with the diesel, however, this part of maintaining a diesel has to be observed if the diesel engine, full system, and/or turbocharger are going to live as long as they should.
Oil change intervals are critical. Most people recommend every 3,000 miles under normal driving conditions and even more often under heavy loads or extremely dirt conditions. A high quality oil with at least a CD rating should be used. Multiviscosity oils are okay as long as they meet the CD rating, climate is important when determining whether or not to use a multiviscosity oil.
Most fuel systems rely at least partially on the diesel fuel to lubricate close tolerance components. It is very critical to keep the diesel fuel clean and free from water and other contaminants. If water is ever evident in the fuel system, it needs flushed out immediately. If the fuel filter is trapping the water you should probably check the fuel tank for more evidence of water. Water can be picked up with the fuel from a fuel supplier or may be a result of continued condensation, especially in the spring or fall when days are warm and nights are cool. Getting fuel from a reputable dealer is always a good idea and keeping your tank full as much as possible will prevent condensation. Once water has been removed from the fuel system, bacteria can still grow in the fuel. This bacteria is introduced by the water but can use the diesel fuel as a medium to feed and multiply. This bacteria will coat internal pump and injector parts and eventually cause performance problems. The bacteria can only be eliminated by killing it with a biocide fuel treatment and filtering out of the fuel. In extreme cases the fuel system, fuel lines, and fuel tank must be removed and cleaned in order to eliminate all of the bacteria from the system.
Over the past several years the lubrication quality of the diesel fuel has been questionable. The process that removes the sulfur from the fuel also deteriorates the lubrication quality of the fuel, as of yet there is still no lubrication standard agreed to by fuel manufactures and although some suppliers claim to add a lubricant back to the fuel each time a consumer fills their tank the lubrication could be different. The only insurance a diesel owner has against premature wear due to low lubrcity fuel is to add their own lubricant. There are several additives on the market that may supply the lubrication, however owners should stay away from any additive containing alcohol. Also getting the most for your money should also be a consideration. Consideration of other advantages. The additive may provide such as winterizers, cetane improvers, cleaners, etc. as well as quantity of treatment per gallon of diesel should be made when looking at getting the most for your money.
Since most diesel engines are now turbocharged, a few tips for prolonging the life of the turbo may be in order. The same oil change intervals mentioned earlier should be followed. The most common failure of automotive turbos is due to hot shutdown. This occurs when the vehicle has been running at a constant speed for a period of time and the vehicle is shut off before the turbo has had time to slow down. A turbo can spin at speeds exceeding 100,000 rpm, the faster the vehicle goes or the harder it works, the faster the turbo will spin. If a vehicle is shutoff suddenly the turbo will continue to spin without oil. Each time this occurs, the life of the turbo is shortened because of wear occurring from no lubrication. Eventually there will be enough wear to allow one of the wheels on the turbo to contact its housing. This causes the wheel to be out of balance. This causes even more contact and the turbo is usually destroyed. Allowing the vehicle to idle for a few minutes after its been running hard or allowing the exhaust temperature to cool to below 500 degrees will greatly reduce the risk of premature turbo failure.
Remembering the above situations and using common sense will allow miles and miles of life for your diesel engine.
BREAKING IN A DIESEL ENGINE . . .
"Breaking-in" a new diesel engine... You may immediately come up with some questions such as… Why did Difflock.com publish an article about something that is a non-issue? I thought newer engines were manufactured with precision crafted parts? According to the manufacturer, there is supposed to be “no break-in necessary”? Many of the engine manufacturers claim that their engines do not require break-in. That is just pure baloney! Enough pestering and a few references to some of the Cummins shop manuals have painted a clearer picture. All engines require some kind of break-in period. This is even true with current technology. Although current technology provides the means of manufacturing engine parts with unimaginable precision, the manufacturer still falls far short of achieving the near perfect fit that a proper break-in will provide. “Break-in,” for the most part, is the allowance of the machined cylinder and ring surfaces to conform to each other’s shape during engine operation. This conforming or “mating” of ring and cylinder surfaces is the ultimate goal of a proper break-in. “Mating” these two specific parts will produce a very tight seal in each cylinder. A tight seal is very important because it prevents the escape of unburned fuel and pressurized gasses into the crankcase, while further preventing crankcase oil from entering the cylinder above the top compression ring. It is the intention of this article to help people understand more about the break-in process, and what happens or can happen during the first few thousand miles of engine operation.
During break-in, a small amount of compression blow-by, oil-fuel dilution, and oil consumption will be experienced. This is perfectly normal and quite common in new engines. Although acceptable at first it is imperative that these undesirable attributes be as close to zero as possible after break-in has been completed. Although the others are important, blow-by is the primary reason the ring and cylinder wall interface has to fit together so tightly. Diesel fuel needs to be introduced into an air environment that is under intense pressure in order for it to burn without an ignition source. When the fuel burns, the gasses produced multiply the compression pressure in the cylinder. Pressurized gasses that escape by means of the compression ring / cylinder wall interface are called blow-by gases. Pressure that escapes the cylinder in this manner results in a loss of energy. Whether it is pressure lost on compression or combustion, it is unable to be utilized to drive the piston through the power stroke. This loss ultimately results in a reduction of fuel mileage and power.
Today’s Diesels can take a "few" miles to fully break in. 10,000 miles is not an uncommon break-in period, especially for an engine like the Power Stroke Diesel. The reasons that break-in is such a lengthy process are generally attributed to engineering targets as well as the function of diesel combustion.
In terms of engineering targets, engine manufacturers produce diesel engines to sustain high torque loads over constant and extended load intervals. In other words, very durable parts are required to hold up to the rigors of diesel operating conditions. For example, The International Truck and Engine Company employs some very special parts in their 175 - 275 hp engines. The pistons used in these engines are manufactured from lightweight aluminum alloy, and are constructed with Ni-Resist ring inserts. The aforementioned piston combination is further complemented with keystone plasma faced rings. These rings help reduce oil consumption and can extend the life of the power cylinder further than ordinary chromium-plated rings. While chromium-plated rings continue to be produced for both diesel and gasoline applications, they are slowly becoming old technology. They still perform well but plasma faced rings have consistently shown superior performance.
When we consider the function of diesel combustion, we must first understand the engine dynamics that are associated with that process. In order for break-in to occur, a fair amount of heat, friction and resulting wear will have to take place before the compression rings will have “mated” with the cylinder walls. When the rings and cylinder wall are new, a modest amount of heat is created merely from the friction of the new rings passing over the freshly honed cylinder wall. While the heat from friction is significant, the real heat is created from combustion of fuel in the cylinder. When the fuel is burned, gasses are produced that expand and heat all of the cylinder parts. If enough fuel is introduced, the resulting combustion can create gasses that expand so much they will actually expand the cylinder wall and the compression rings. It is important to understand this because expanding these parts places additional pressure on them, which creates more friction and correspondingly more heat. This does not take into account the additional heat from combustion that will be added to the heat from friction. Heat is important to assist wear for break-in but too much can cause major problems. This is the reason we should not subject the engine to significant loading for the first 1000 miles of its operation. Loading heavily will introduce more fuel to the cylinder, and will add significant amounts of heat and pressure to the cylinder components. Couple that scenario with new rings on a freshly honed cylinder wall and we can only imagine the amount of friction and heat being produced and absorbed by the rings.
Furthermore, the engine oil, lubricating the cylinder walls, will flash burn when it contacts the very hot rings. The burned oil will leave a hard, enamel like residue on the cylinder wall, commonly known as oil glazing. When the rings are permitted to operate under such high temperatures, oil glazing of the cylinder can happen very quickly. Once this glaze builds up, the only repair is a labor-intensive process that requires disassembling the engine and re-honing the effected cylinders. Oil glazing is a problem because it is typically not distributed evenly in the cylinder, and the spaces that exist between the ring and cylinder wall are either still there or new larger ones are created. Oil glazing is typically thicker towards the top of the cylinder and it builds up in the areas where heating is the greatest. The glaze has very smooth and friction free properties that do not allow it to be scraped away by the rings. This inhibits further metal-to-metal wear between the cylinder wall and rings, preventing further mating of ring and cylinder. Thus, those small gaps between ring and cylinder surface will never seal. These spaces will then allow pressurized gasses and unburned fuel to escape into the crankcase, while allowing oil from the crankcase to enter the cylinder above the top compression ring.
Well why not run the engine at idle or under no load? This is bad too. It can create a similar condition to glazing. The rings need to expand a little during this initial break-in period, just not so much that they overheat and flash the engine oil. The engine needs to be moderately loaded in order to break in correctly. Running the engine under very light or no load prevents the oil film placed on the cylinder wall from being scraped away by the expanding compression rings. The rings will instead “hydroplane” or ride over the deposited oil film, allowing it to be exposed to the cylinder combustion. The oil film will then partially burn on the cylinder leaving a residue that will build up and oxidize over time. Eventually this leaves a hard deposit on the cylinder wall that is very similar to the glaze left from flash burning. My caution to those just running the engine as a normal daily driver (without some loading) and especially those who love to idle their vehicles, expect some VERY extended break-in periods (up to 30,000 miles on one I know of). Expect oil consumption forever due to oil glazing. The rings never really seat well if they cannot expand from the dynamics and heat that a load produces. Expect poor mileage due to the passing of compression and combustion gasses around the compression rings. Additionally, expect to see increased bearing wear and engine wear due to the fuel passing the rings diluting the engine oil.
Thus, we can see that heavy loading and light loading can cause some major problems. Moderate loading is the key to a proper break in for the first 1000 miles. It permits the loose fitting piston rings to expand into the cylinder walls allowing them to perform double duty: First, scraping oil off the cylinder wall, and second, to create friction that will promote wearing the two surfaces to each other’s proportions. Furthermore, moderate loading will allow the rings to get hot but not to the point where it will flash the lubricating oil supplied to the cylinder walls.
Once the rings and cylinder have "mated," they will have worn away a considerable amount of their roughness. They will wear slower than they did when they were new. This reduced wear rate indicates the end of break-in, and a decrease in oil consumption should be obvious to the owner / operator. Furthermore, blow-by and fuel dilution should also be reduced but may not be so obviously evident. Be aware that engines employing Plasma faced ring technology will take a longer time to break-in. These rings tend to wear far slower than chromium-plated rings. The plasma ring’s hardness allows it to wear the cylinder wall in a more aggressive manner while only polishing the ring surface. Eventually the cylinder wall wears to the shape of the ring and subsequent cylinder wear evolves to a polishing process. This extended process drastically improves the sealing potential of the cylinder, which will correspondingly reduce blow-by and the amount of physical wear on these components. Therefore, we can safely say that the plasma faced ring / Ni Resist insert combination greatly extends engine life. Unfortunately, the price of this better seal is a longer break-in period.
So the big question is: How long does it take for an engine to break-in? Outside of the rings being hard as rocks and just taking their own sweet time to mate to the cylinder bores, the greatest factor is how the engine is broken-in. Most engines will be broken-in after running for some time, but some ways of breaking-in an engine are far superior to others as they are more likely to produce low blow-by and near zero oil consumption.
Therefore, I will lay out some recommended DOs well as definite DON’Ts:
1. DON'T run the engine hard for the first 50 to 100 miles. It is recommended that the engine be operated around the torque peak (1500 to 1800 RPM) in high gear. This loads the engine very gently, and allows the internal parts to "get acquainted" without any extreme forces.
2. DON'T let the engine idle for more than five (5) minutes at any one time during the first 100 miles. (Even in traffic.) Remember those loose fitting rings, and possible fuel-oil dilution that were noted above? (Fuel Dilution is very common when diesels idle, even with well broken-in engines.) Well, if that fuel is allowed to contact the main and rod bearings during break in (not really good at any time), you might be looking at an engine that will always consume some oil and one that may not produce power or mileage as expected. In the first few miles of break-in, the bearings are mating to the crank, rods, etc. It is imperative during this time that the lubrication qualities of the oil remain robust. Fuel in the oil will reduce its ability to absorb shock and float the rotating parts in their bearings. Contact between bearings and journals will occur more frequently which will result in additional friction wear. This will ultimately reduce the tight tolerances between the bearings and journals. What was originally a tight fit will be sloppy and will never be able to mate properly.
3. DO drive the engine at varying RPMs and speeds until about 1000 miles. The idea is to alternately heat and cool the rings under varying RPMs. Manual transmission-equipped trucks are the best for this as they typically employ engine compression to slow the vehicle during normal operation, this constantly allows for varied RPMs. This can also be done with automatic transmissions, but it requires that you manually downshift the transmission into the lower gears while driving. Typically, most people with automatic transmissions operate their vehicles in Drive or Overdrive gear positions without making these manual shifts. When their vehicle is decelerating and the speed falls below 38 mph the transmission has little influence on engine RPM. This is because the torque converter unlocks and the auto transmission does not downshift to lower gears in the same fashion that manually shifting does. My suggestion to those with auto transmissions is to find an empty parking lot in the evening, and drive back and forth across it in the lower gears. (This can be done with standard transmission trucks as well.) Each time revving her up close to redline and letting engine compression slow it back down. This gets the rings a bit hot, but the compression braking allows the pistons to cool with high oil spray flow and no fuel load. Keep doing this for a number of runs, or until boredom sets in.
4. DO put a load on the engine at around 1000 miles, and get the thing hot! Diesels are designed to work, and in many cases, they operate best under a load. Baptize your engine with a nice "initiation load," to introduce it to hard work. Keep the revs up (but watch the EGTs), and make sure the coolant temps rise. Hooking up your trailer and finding some hills to pull works great for this. After the 1000 mile pull, just drive it normally, always making sure to let the engine get up to normal operating temps (no 1-mile trips to 7-Eleven). Towing is ok but remember to not overload and to monitor your gauges carefully erring on the side of caution. Under these conditions, I have seen most diesels completely break-in between 10-15,000 miles, and have always been able to tell that point from mileage gains. One may also notice that the "symphony" of the engine also changes slightly at this point.
We know that Engine Manufacturers have built today’s diesel engines using state of the art technology. They have fashioned parts to match in near perfect fashion. We can understand, through this article, that breaking-in this modern marvel of technology is more important then the manufacturers have lead us to believe. Furthermore, we can appreciate that following their claims can result in an engine that is wrought with inefficiency, sloppy fitting parts, and oil consumption problems. Following the guidelines and warnings set forth in this article will provide anyone who desires maximum efficiency and power out of his engine many miles of trouble free operation.
