New and Used Engines are subjected to stringent testing by vehicle manufacturers and engine builders to gauge the efficiency and quality of certain engines and engine parts. An engine test stand is a facility used to develop, characterize and test engines for this purpose. The facility, often offered as a product to automotive manufacturers, allows engine operation in different operating regimes and offers the measurement of several physical variables associated with the engine operation through development phases and scientific engineering.

A sophisticated engine test stand, which is also a dynamometer, houses several sensors and data acquisition features and actuators to control the engine state. The sensors would measure several physical variables of a new or used engine which typically include: The crankshaft torque and angular velocity. The measuring of intake air and fuel consumption rates in new and used engines, often detected using volumetric and/or gravimetric measurement methods. The air fuel ratio for the intake mixture and the exhaust gas, which detects amounts of carbon monoxide and different configurations of nitrogen oxides and sulfur dioxides of the emmissions. Temperatures and gas pressures at several locations on the engine such as engine oil spark plug, exhaust gass, and intake manifold temperatures, pressures and atmospheric conditions of the engine are critical to determine how well a particular engine part holds up at different stages of its life measured in distance or the time the engine has endured.

Information gathered through the sensors is often processed and logged through data. Actuators allow for attaining a desired engine state. For gasoline engines, the actuators may include an intake throttle actuator, a loading device for the engine such as an induction engine. The engine test stands are often custom-packaged considering requirements of the OEM customer.

The vehicle manufacturers have through extensive testing from the new factory engine to hundreds of engines which have completed hundreds and thousands and even hundreds of thousands of hours of testing. These test stands give the engineers a profile to ‘go on’ giving indications as to how well an engine part should be made to last in order for the warranty period of a used engine to be fulfilled. Even oil changes have been scientifically predicted. Instead of a new engines first oil change to be administered at 10,000 km’s, the manufacturer stipulates the first change at 15,000 km’s.

If an engine part is too well made there would be no market for aftermarket auto spares as the engine would outlast the vehicle. The entire motor industry would be a failure including automotive scrapyards that provide a re-cycling of auto scrap and spare parts essential to not only the industry but also to the environment and future of our fragile planet earth. Vehicle manufacturers have to make money and would not succeed in the market place without doing these critical tests on new and used engines at different intervals and under various operating conditions.

For more information   CLICK HERE “Used Engines / Engine Parts / Scrapyards”  or Call Centre :  0861 7777 22

There are hundreds of large and very well stocked auto parts and Engine Parts suppliers in South Africa. These suppliers stock anything from cast and forged pistons, piston rings, cylinder liners, valves and valve seats and valve guides, conrods, crankshaft and connecting rod bearings for big ends and main bearings, bushings, sealing products and gasket sets, belt tensioners, water pumps, oil pumps, turbo and fuel injection parts and almost any other engine parts for automotive and commercial vehicle engines available.

Scrap Yards are also suppliers of engine parts. These engine parts become available when an engine has sustained serious damage and the engine has been put aside for stripping of parts. Often these engine parts can be purchased at less than half the price of a new part or pirate part fr4om a motor spares outlet, generally who stock copy cat parts or pirate parts. Some of these engine parts are not manufactured as well as the original equipment manufacturers parts (OEM) parts.

It often pays a person to buy used auto engine parts like crankshafts, conrods, cylinder blocks and cylinder heads from scrapyards if you are knowledgable enough to re-condition an engine yourself. If you know what you are doing you can save a lot of money this way. The trick is to know what parts to buy and caution must be exercised when venturing out to a seller of such used engine parts or any auto or commercial parts. Some ‘engine parts’ may look the same but are far from the correct engine part that you require for your engine build. Remember that it is up to the buyer of the parts to know what he or she is purchasing so therefore take along someone who knows and don’t rely on the knowledge of the seller or scrapyard salesman. These guys are there to sell stock and more than often do not know exactly what your requirements are. Once you have paid for engine parts it will be hard to get your money back, so be sure when paying hard earned cash for the wrong part.

Engine parts such as pistons, gaskets, seals and big end and main crank bearings should be purchased new. Secondhand parts will inevitably not last and you will end up doing the job again. Buy your aftermarket engine parts from a reputable motor spares supplier as parts of this nature are perfectly okay to use providing good quality aftermarket engine parts are installed. Your supplier

For more information   CLICK HERE  “EngineParts / Motor Spares / Scrapyards”  or  Call Centre :  0861 7777 22

A warranty may be express or implied depending on what you bought. Secondhand Parts for a motor vehicle may guaranteed by the seller for a certain period of time. In business transactions, a warranty or guarantee, is an assurance by one party to the other party that specific facts or conditions are true or will happen and therefore the other party is permitted to rely on that assurance and seek some type of remedy if it is not true or followed.

Secondhand parts are often bought from Scrapyards, the automotive ‘supplier’ of spares, which are often referred to as the ‘used auto parts supplier’ or sometimes from a private induvidual. The auto or commercial vehicle spares are normally sold ‘as is’ or ‘foetstoets’. This means that the used auto parts are accepted by the ‘buyer’ without conditions attached to the sale agreement. Sometimes, ‘the supplier’ of an engine will furnish ‘the buyer’ with a 1month start-up guarantee. This form of guarantee is usually a promise from ‘the supplier’ to ‘the buyer’ that the engine will start and no more.

When buying secondhand parts it is up to ‘the buyer’ of the goods to understand and know what they want to purchase. Once the money is handed over the deal is concluded, providing and for example, the fruit that looks and smells good but has hidden defects would violate the implied warranty of merchantability if its quality does not meet the standards for such fruit "as passes ordinarily in the trade".

The warranty of fitness for a particular purpose is implied when a buyer relies upon the seller to select the goods to fit a specific request. For example, this warranty is violated when a buyer asks a mechanic to provide secondhand tires and receives tires that are unsafe to use in ice, snow and wet weather conditions. This implied warranty can also be expressly disclaimed by name, thereby shifting the risk of unfitness back to the buyer.

Some companies also offer secondhand extended warranties or used car warranties for vehicles up to 12 years old. The term extended warranty. Non-manufacturer based warranties are technically called motor vehicle service agreements or service contracts.

South Africa has a wealth of scrap yards and used spares suppliers that can supply the secondhand parts you may require. Always compare as per your sample and inspect the parts carefully before paying. Make use of your national Spares Locator Service LOOKING 4 SPARES. Visit the website HOME page and make use of the ‘Safe Trade Account’. This is your Payment Protection Facility when buying spares at a distance.

For more information  CLICK HERE “Scrapyards / Secondhand Parts / New Spares”  or Call Centre :  0861 7777 22

This engine design manages to pack one power stroke into every two strokes of the piston.

1. Compression stroke: Fuel-air mix is compressed and ignited.

2. Power stroke: The piston is pushed downward by combustion and hot exhaust gases.

When the piston moves from bottom dead center (BDC) to top dead center (TDC) the fresh air and fuel mixture enters the crankcase chamber through the intake port. The mixture enters due to the pressure difference between the crank chamber and the outer atmosphere.

In a two stroke spark ignition engine, a cycle is completed in two strokes of a piston or one complete 360º revolution of the crankshaft. The two-stroke engine uses an intake and an exhaust port instead of intake and exhaust valves. Petrol is mixed with two-stroke oil for lubricating the piston and crankshaft or the carburetors ‘autolube’. As the piston proceeds downward another port is opened and the oil/fuel/air mixture enters the intake port. Air/fuel/oil mixtures come from the carburetor or fuel may be pre-mixed usually at a ratio between 20:1 and 30:1. When the piston moves further down and the cylinder doesn't have any more gases, fuel mixture starts to flow to the combustion chamber and the second process of fuel compression starts.

The piston acts as the combustion chamber with the cylinder and compresses the air/fuel mixture, receives back the liberated energy, and transfers it to the crankshaft. The piston motion creates a vacuum that sucks the fuel/air mixture from the carburetor and pushes it from the crankcase to the combustion chamber. The sides of the piston act like the valves, covering and uncovering the intake and exhaust ports cut out in the side of the cylinder sleeves wall.

With the help of a spark plug, ignition timing takes place at the top of the stroke or TDC. Due to the expansion of the gases the piston moves downwards covering the intake port and causes the fuel-air mixture inside the crank chamber to be compressed. When the piston is at bottom dead center the burnt gases escape from the exhaust port out into the exhaust pipes expansion chamber.

At the time the transfer port is uncovered the compressed charge from the crank chamber enters into the combustion chamber through the transfer port. The fresh charge is deflected upwards and removes the exhaust gases from the combustion chamber. Again the piston moves from bottom dead center to top dead center and the air/fuel/oil mixture is compressed when the both the exhaust port and transfer ports are covered.

Two-stroke engines have some advantages over a four-stroke engines. Two-strokes have no valves or camshaft mechanisms, simplifying its construction. Four-strokes execute one cycle per two crankshaft revolutions thus halving the process. It weighs less and is easier to manufacture and produces a high power to weight ratio.

Two stroke engines also come with disadvantages, Engines have a shorter life due to an inefficient lubrication system. They also do not consume fuel efficiently, thereby producing excessive pollution.

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