Showing posts with label Tractor Repair Tips. Show all posts
Showing posts with label Tractor Repair Tips. Show all posts

Monday, 28 November 2011

What is a Long Block and How Is It Best Used

Repairing an engine by a complete overhaul is a popular way of maintaining tractor engines, and ensuring continuous problem free operation of heavy duty machines. However, the overhaul process can take a minimum of five (5) days if all of the parts are readily available for the overhaul, and typically approximately ten (10) days for the complete overhaul to be completed, with the additional time to procure the parts needed for the overhaul.

Depending on what needs to be repaired on the old engine, a complete block assembly engine, or a long block as it is sometimes called, can be faster repair job for a tractor engine that requires a new block and a cylinder head.

The short block comprises of the cylinder block and the crankcase connected by a connecting rod and precision heavy duty welding. The long block is the next level in engine repair, as compared to the short block. The long block has additional components that make repairs less tedious.

The most significant addition that makes up the long block is the cylinder head. This is bolted to the top of the cylinder block by head bolts and sealed with a head gasket. Depending on the engine model and manufacturing company, the cylinder head can contain a section of the combustion chamber. All will have the intake valves, exhaust vales, valve springs, valve keepers, and the rocker arm assembly. The rocker arm assembly comprises of the rocker arm shaft, tappets, push rods, and the rocker arms. The camshaft assembly in the crankcase moves the push rods which mechanically operates the rocker arm assembly.

Both the long block and the short block will have the front gear train, with pulleys and chains. However, the long block will have the front plate, which is a protective covering for the gear train components.

In some models, the rear seal housing with the seal is provided. For example, the 6081 John Deere engine long block, this housing is provided as a part of the complete engine assembly.

The oil pump and oil pump accessories are another pertinent addition to the long block assembly. The exact location of the oil pump varies by engine type and manufacturer, however, a large percentage of oil pumps are fitted in the lower section of the crankcase, with an oil filler tube extending downwards into the area where the oil pan will be located. At the bottom of this filler tube, is fitted an oil strainer.

The long block would have been fitted internally with many gaskets, including the front gear train gasket, the oil pump gasket, the head gasket, and a few others. However, since there will be many engine accessories to be added to the external parts of the engine, a complete gasket kit is normally shipped with the engine assembly. This will include gaskets for the exhaust and intake manifolds, water pump, fuel pump and fuel transfer pumps.

For completely remanufactured engine assemblies that were rebuilt to OEM specifications, all internal components used in the rebuilt process will be new components, with the exception of the blocks, cylinder head, and crankshaft which are typically rebuilt to OEM specifications and reused.

Ontario Parts Hotline is a premium provider of Deutz Tractor Parts and Deutz Combine Parts.

What is a Short Block and How Is It Best Used

Replacement engines for tractors, combines and other heavy duty equipment are available in different configurations and types. The choice on which to choose will depend on several factors, including the damage to the present engine, and how much down time can be absorbed.

A problem that sometimes necessitates an engine block replacement arises from loose main bearings, which when spun out, can cause a broken connecting rod that violently breaks and punches through the side of the engine block. There has been examples where the connecting rod punches up into the cylinder head.

In such examples, all other engine components are in perfect working condition, however, the bottom section of the engine needs to be replaced. In engine terminology, the bottom section of the engine is called a short block. Large tractor engines are typically made up of four major components, joined together by smaller components and with accessories attached to the external areas of the engine.

The four major components of a large tractor engine are the cylinder head at the top, the cylinder block under the cylinder head, the crankcase under the cylinder block, and the oil pan at the bottom of the crankcase.

The short block engine comprises two of these, namely the cylinder block, and the crankcase. In the automotive field and lawn mower manufacturer which uses small engines, the cylinder block and the crankcase is casted as a single casting during manufacture. However, in large tractor engine and marine engine manufacture, the cylinder block and the crankcase are manufactured as separate castings and then joined afterwards by welded steels plates and precision heavy duty welding. The cylinder block and the crankcase serve different complimentary functions.

The cylinder block is the section of the engine that houses the cylinder liners, the piston assembly and the camshaft. The top section of the cylinder block is called the combustion chamber. On the top of this assembly is bolted the cylinder head. The cylinder head is not a part of the short block engine.

The bottom section of the short block engine is the crankcase. This section of the engine houses the crankshaft, main bearings, crank seals, and front gear train. The combination of the cylinder block and the crankcase is called the short engine block. The two components are welded together, and internally, are connected by the connecting rods, hence the term, "connecting" rods. Motive power is transferred from the piston movements to the crankshaft via the connecting rods.

Short engine blocks removed from salvaged tractor yards are called good used short blocks. Used engine short blocks that were totally overhauled, replaced with new or rebuilt internal components, and restored to OEM specifications are called rebuilt short blocks. OEM companies may have their own abbreviations for their engine, i.e., John Deere will refer to their reconditioned engine blocks as John Deere Reman, and Caterpillar will call theirs Cat Reman. OEM reman products typically carry the new product unlimited use warranty, when installed by the dealer's mechanics.

Ontario Parts Hotline is a premium provider of Deutz Tractor Parts and Deutz Combine Parts.

The Functions of Tractor Radiators

The most efficient tractor engine will utilize approximately 35% of its energy into useful actions of driving, plowing, pulling, transporting and other farm duties. The excess 65% of energy produced will be lost in the form of sound energy, heat energy, radiant energy, vibrations, and friction.

A sufficiently cooled engine, and its counterpart, a sufficiently hot engine, are both necessary for optimum tractor engine performance. An over cooled engine can cause excessive damage to the engine components. Pistons and liners are designed to maintain very specific and minute clearances.

An over cooled engine will have its liners cooler than the hot pistons. The aluminum pistons typically expand faster than the steel based liners, and therefore, there will be scarring between the two surfaces. This damages the pistons, piston rings, and liner surface.

An excessively hot engine will cause all internal components to expand beyond normal tolerances, producing loose components, and burnt tractor engine parts. This is a phenomenon that is referred to as a "shot" engine or "seized" engine by mechanics. The tractor radiator removes excessive heat from the engine. The coolant that is circulating through the engine is allowed to be cooled via the tractor radiator.

The thermostats aids in this cooling process by preventing heated coolant from leaving the engine during the startup phase when the engine is cold, and allowing coolant to flow through the radiator when the engine temperature is above design temperature limits. The tractor radiator can be manufactured from aluminum or copper or alloys of aluminum or copper. Aluminum or copper is used as both have a high heat capacity, which is the capability to absorb and release a large amount of heat very easily.

The tractor radiator basically has rows of tubes, and onto these tubes are attached thin strips of metal. The coolant is forced through the tubes the water pump. Typically, the coolant flows from the top of the radiator, downwards through the tubes, and back into the engine block. Specially designed radiator hoses perform these high temperature connections between the engine and the radiator.

Onto these rows of metal tubes, are fitted thin strips of identical or similar metal. This effectively increases the surface area of the tubes, allowing the heat form the coolant to travel by conduction to the fins. The fins are typically designed as fins per inch. The 8N Ford tractor radiator and the David Brown radiator model 990 has eight (8) fins per inch, the Allis Chalmers radiator for the D17 has seven (7) fins per inch, the John Deere radiator for model 3020 has ten (10) fins per inch.

The other main component of the cooling system is the radiator cap. This serves to maintain a high pressure in the radiator, thus preventing the coolant from boiling, and it acts like a pressure relieve valve releasing coolant to the reservoir when hot, and pulling coolant into the engine when cold.

Ontario Parts Hotline is a premium provider of Deutz Tractor Parts and Deutz Combine Parts.

Understating Why Diesel Engines are Hard to Start in Cold Weather

Attempting to start Diesel engines in cold or sub zero temperatures is extremely difficult and usually an impossible task, unless appropriate accessories has been added to the engine to assist in such starting.

The hard starting problems of diesel engines in below zero / freezing temperatures are caused by two factors. One is the initial cold air being drawn into the turbocharger and compressed into the engine’s cylinder head. The second is the fuel itself, is also cold and this sub zero / freezing temperature fuel is sprayed into the cold engine’s combustion chamber, where it mixes with the cold air drawn thru turbocharger.

Additional problems will result from fact that a cold starting diesel engine needs to reach at least two hundred (200) rpm to develop a four hundred (400) psi compression pressure to sufficiently compress the air to fuel mixture, and thus, resulting in combustion.

These two problems will result in the diesel fuel being sprayed into the combustion chamber, and it will condense on the cold surfaces of the cylinder liners or cylinder block. This liquid fuel will seep through the piston rings, and fall into the engine’s crankcase, diluting the lubricating oil in the process.

Two simple devices can be used to reduce the possibility that these conditions occur. One is by the use of battery heaters and glow plugs. No one device can be used. Usually a combination of several devices will provide an overall efficient starting process.

The efficiency of a battery drops as its temperature drops. A battery that is fully charged at 26 degrees C (80 degrees F) will have its starting capacity drop to approximately forty six percent (46%) available power at 17.7 degrees C below 0 (0 degrees F). Additionally, at this temperature, the engine will be approximately two and a half (2.5) times harder to start at -17.7 C (0 F) degrees due to thicker oil and resistance to movement of internal moving parts. This gets worst at lower temperatures are experienced.

To solve this, one of two common devices is used to heat the battery. One is a padded silicone covered, acid resistant rubber hot pad heater. This operates off of 110/120V and comes in various wattages. The power range can be 60W to 500W, and this can be used to heat the batteries, engine oil pan, fuel tank, hydraulic tank, and the water tank.

The other device that is typically used in conjunction with the hot pad is the glow plug. This is an internally fixed low voltage heating element that is fitted directly into the combustion chamber. When this is switched on, it can take up to two minutes to heat up, however, by that time it has reached approximately 700 degrees C (1652 degrees F) and the combustion chamber is hot enough to prevent the condensing of the diesel fuel, and thus, ignition is guaranteed.

Ontario Parts Hotline is a premium provider of Deutz Tractor Parts and Deutz Combine Parts.

Ignition Differences between Gas and Diesel Engines

One of the questions that prospective owners of engine powered equipment typically ask themselves, is which type of power motor is preferred? Should machinery with a diesel engine be chosen, or machinery with gasoline engines is given preference? The answer to that question varies with many parameters, one of which is described below.

One major difference between the diesel and gasoline engines is the manner in which fuel combustion occurs.

With the gasoline engine, there are a few mechanisms that are working at approximately the same time. The basic combustion process is that an appropriately mixed air to fuel vapor is drawn into the combustion area above the piston head, (located in the cylinder block), and then the spark plug provides a spark for ignition to occur. This process is a rapid explosive exothermic reaction. The rapidly expanding gases push the piston downward, turning the crankshaft via the connecting rod, and hence motive engine power.

The spark ignition process begins with power being supplied from the battery. This 12v (or 24v) power is fed into an ignition coil, which increases the voltage, while at the same time reducing its current. The result is a high potential difference that is now delivered to the distributor.

The distributor is a combination of electrical and mechanical components, however, since it’s not under discussion here, its function is simply to deliver the high potential difference from the ignition coil, to the spark plugs, via the spark plug wires (or leads), in a timely fashion.

None of the above components, namely the ignition coil, distributor, spark plugs, and spark plug leads are found in the diesel engine.

Combustion in the diesel engine occurs in a slightly different manner. The air to fuel mixture is first pushed into the cylinder combustion area, and then the valve closes at the same time the piston is moves upwards. The air / fuel mixture is highly compressed in the combustion chamber, to such as extent that the mixture simply ignites by itself without the need for an external ignition source like that provided by a spark plug.

Therefore, the first advantage of the diesel engine over the gasoline engine is simply less components to fail, and therefore less maintenance issues.

The air to fuel mixture in gasoline engines occurs in a carburetor in older tractor engines. Modern gas engines use a fuel injection system.

All diesel engines uses fuel injector pumps and fuel injectors as part of the fuel system that provides fuel to the engine. This fuel is injected directly into the combustion chamber, just before the piston reaches TDC (Top Dead Center) position.

Ontario Parts Hotline is a premium provider of Deutz Tractor Parts and Deutz Combine Parts.

How to Identify Classical V Belts Dimensions for Tractors

There are more than sixty six (66) various dimensions, sizes and types of belts that are used in the agriculture equipment industry. These various belts are used in tractors, combines, balers, snow blowers, tillers, mowers, harvesters and lawn and garden tractors.

V Belts are used as fan belts, timing belts, alternator belts, drive belts for mowers, and general pulley driven devices found in combines, mowers, balers, harvesters and other agricultural equipment.

To change a cut or damaged V belt, it must first be identified. The fastest and easiest way to identify a belt is to deduce the V belt part number that is written on it.

However, in practice, sometimes this is not possible, and then other methods must be used. The basic V belt has a trapezoidal cross section, with equal sides, and different lengths at the top and bottom. There are five popular (5) basic v belt types (called Classical V Belt), and these are defined as A, B, C, D and E. Models Z and F will not be covered here. Each V Belt can have its part number described by utilizing five key dimensions, namely, the top width pitch width, height, angle and true circumference.

The A model has a top width of 13mm (1/2 inch) and a height of 8 mm (5/16th of an inch).
The B model has a top width of 17mm (21/32nd of an inch) and a height of 11 mm (13/32nd of an inch).
The C model has a top width of 22 mm (7/8th of an inch) and a height of 14 mm (17/32nd of an inch).
The D model has a top width of 32 mm (1 1/4th of an inch) and a height of 19 mm (3/4 of an inch).
The E model has a top width of 38 mm (1 1/2th of an inch) and a height of 23 mm (29/32nd of an inch). All classical belts have angles of 40 degrees.

The other major variant of this component is its length. The normal outside and inside circumference of the belt can be measured. However, for measuring and part number identification purposes, this is not the true circumference. The effective circumference of the belt is the part of the belt that most of the pressure is concentrated on while under word pressures (called pitch length). This line is generally located at the neutral axis near the cord line and varies with cross section and construction. This circumference is typically a few millimeters under the top width of the belt.

Some manufacturers and users prefer the pitch length to identify belts. However, most users tend to use the inner circumference of the belt for identification purposes. For example, a belt with a “C” dimensions and an inner length of ninety five (95) inches will have part number of C95. This description can be used to identify the other types for the A, B, D, Z and E.

Ontario Parts Hotline is a premium provider of Deutz Tractor Parts and Deutz Combine Parts.

What are Wet Sleeves and How are They Used

Cylinders liners are called several names in industry. It can also be referred to as sleeves. Thus, cylinder liners and cylinder sleeves are one and the same thing.

The barrel or bore that the piston moves up and down may be either integral with the engine block, or be a completely replaceable separate item. Most diesel engines come with replaceable cylinder liners. The most common agricultural tractor with a sleeveless or liner less engines are some of the Ford / New Holland engines. Most of the other, including, John Deere, Farmall, Allis Chalmers, IH, Case, David Brown, Massey Ferguson, Perkins, Cummins and Kubota are predominantly sleeved engines.

The primary advantage of using a cylinder liner is that it will become damaged after the robust process of movement and combustions that occurs in it. At the top of the sleeve (in the combustion chamber) the temperature can be as much as 593 degrees Celsius (1100 Fahrenheit). The piston reciprocates in this cylinder liner at a speed of approximately 1800-5000 rpm, depending on application and design.
Replaceable liners can be easily pressed out, and a new liner be pressed in. There is portable equipment to perform this pressing in and out right on the machine, without the need for transport to a machine shop. However, the larger diesel engines will require removal from the machine and transport to the machine shop for full liner /sleeve replacement.

Another advantage of using sleeves / liners is that the engine block can be manufactured with less expensive cast iron, while the liners are manufactured with special alloys, making it tougher, harder, and resistant to heat and wear. These added alloys can have chromium, nickel, or molybdenum.

Engines with the bore directly into the engine block, like Ford Tractor engines, are referred to as “wet sleeves,” as the coolant circulated directly onto it, being cooled by convection. The blocks with are referred to as “dry sleeves” are cooled via conduction heat transfer.
After the initial wear and tear or operation, the engine block itself is re-bored to a larger diameter to fit oversized pistons. With repeated re-boring, there comes a time where re-boring has reached its limits, and a replacement cylinder liner has to be bought and installed. Thus, a sleeveless engine can be made into a sleeves engine when necessary.

Ford Tractor engines typically have liners fitted with a ridge or flange at the top. This acts as an added sealing feature, separating the water jacket from the combustion chamber and cylinder head.

The sealing of the water jacket and from the cylinder head is also supported by using specially made o rings that can be fitted to the top and bottom of the liner, depending on application and engine design.

Ontario Parts Hotline is a premium provider of Deutz Tractor Parts and Deutz Combine Parts.

Tractor Engine Cooling Systems and Water Pump Problems

A tractor cooling system comprises of several components, including a water pump and a radiator. These two major components of the tractor’s cooling system differ is its functions, breakage problems, and corrective and preventive maintenance procedures.

A basic tractor water pump is made up of three major parts, and a series of smaller minor parts.

The major three components of the water pump are the outside housing, the central shaft, and the water impeller. One end of the impeller shaft fits into the circular impeller, and the other end of the impeller fits into the water pump housing. The impeller shat fits into the housing via a sealed bearing and a copper bushing called a shaft slinger.

A section of the impeller shaft protrudes from the housing, and onto that is fitted a single or double groove pulley. A key is used to ensure that the pulley does not slip o the shaft.

The continuous rotation of the water pump shaft, which turns the impeller, pulley and fan blades, will wear out over time due to normal wear and tear. The sealed bearing will damage over time, as are the copper bushings. The impeller can corrode overt time by the continuous cavitations of the coolant fluid passing through it.

These damaged bearings and bushings, will give rise to slight vibrations initially, and then to small leakage of coolant through the bearings area. At this time, its advisable to change the water pump .

In older Allis Chalmers, Case, IH, John Deere, Massey Ferguson, Ford, New Holland, Kubota, Deutz, David Brown, Farmall tractors, the water pump pulley is attached to the fan hub. If the leaking water pump is not changed, then there is the risk of the bearing completely breaking apart. This complete braking up will render the pump pulley and hub to rotate in a hap hazard fashion, and the fan blades can actually cut into the radiator, producing additional failed components i.e., the radiator and the damaged fan blades.

In newer tractors the fan blades are electrically driven, and is separate from the water pump.

Regular inspection of the pump can prevent this, or better yet, the pump should be changed after a certain amount of operational hours. A leaking water pump can be quickly repaired using a water pump repair kit. The repair kit components can include an impeller, impeller shaft, gasket, bushings, bearings, and retailer clips.

If the housing of the pump is damaged, then the entire water pump needs to be changed.

On some water pump housings are stamped/casted a number. Get that number and call your parts supplier.

Ontario Parts Hotline is a premium provider of Deutz Tractor Parts and Deutz Combine Parts.

Tractor Engine Cooling Systems and Possible Maintenance Problems

Its farming time whether its tillage, plowing, or just normal farm work. It’s a hot day, and there are lots of things to get done around the farm. However, suddenly you notice that the temperature gauge is showing higher than normal temperature reading. At this time, it’s wise to stop operating the tractor, and if the temperature level is not at its peak level on the gauge, make a quick check of the engine area to detect any leaks or other obvious problems, and then return quickly to turn the engine off.

The older tractors will not have safety shut off devices. The newer computerized controlled tractors will have audible alarms and in many cases, these controls will automatically shut the engine down when excessive temperature readings are present.

A tractor’s cooling system comprises of several components. There is a radiator, a radiator fan, water pump, lower radiator hose, upper radiator hose, a thermostat, and a liquid that flows through the engine, to the radiator where it is cooled, and then recalculated back into the engine to continue the cooling process.

The first step in diagnosing an overheating problem is to ensure that there is enough fluid in the radiator. This can be checked by looking in the overflow container. If that is filled, and there is no blockage from the radiator to the overflow container, then the engine must be allowed to cool. Once cooled, the radiator cap should be removed and the radiator checked for fluid.

If there is a fluid shortage, then the cause of the shortage needs to be identified. A damaged lower and upper radiator hose can be changed. The clamps on the system can be tightened or changed.

For fluid shortage, there should be visible leaks around the failed component, either the hoses, a leaking radiator, or broken water pump. Should there be no visible leaks and missing cooling fluid, then this can indicate a damaged cylinder head gasket that is allowing the fluid to either leak into the engine, or be pulled into the combustion chamber, burnt, and then exhausted.

The thermostat, a simple device, is located directly in the path of the flowing liquid. It contains a bi-metallic disc, that opens when immersed in fluid of a high temperature, and closes when the temperature of the fluid reduced below a predetermined level. Typically, most thermostats will fail in an open manner, thereby allowing overcooling rather that the opposite, overheating.

A simple way to test the thermostat is to put it into a container of water and bring that container to a boil on a stove, or hotplate. As the water temperature reaches boiling, the thermostat should begin to open. If it doesn’t, then it needs to be changed.

Other sections of the cooling system not discussed here are the water pump, and the radiator, gauges and radiator cooling fan systems.

Ontario Parts Hotline is a premium provider of Deutz Tractor Parts and Deutz Combine Parts.