28-08-2014, 12:58 PM
I am submitting my six month industrial training report which i have done from Gulzar Motors (P) Ltd , G.T Road Dholewal , Ludhiana during my training i have gained knowledge about different maruti suzuki cars services and engine repairing processes and methods. I had done a project on Engine Overhauling (An overhauling engine is an engine which has been removed, disassembled (tear down), cleaned, inspected, repaired as necessary and tested using factory service manual approved procedures. The procedure generally involves honing, new piston rings, bearings, gaskets, oil seals. When done by a competent engine builder the engine will perform as new. The engine may be overhauled to 'new limits' or 'service limits', or a combination of the two using used parts, new original equipment manufacturer (OEM) parts, or new aftermarket parts. The engine's previous operating history is maintained and it is returned with zero hours since major overhaul.
ENGINE OVERHAULING
The engine overhauling depends on the performance of the engine.
We may need an engine overhaul when we see one or more of the following indications-
Excessive engine oil consumption Engine bearing noise Piston slap noise Excessive fuel consumption
1. Excessive Fuel Consumption
Oil consumption depends primarily on two things: the valve guides and piston rings. If the valve guides are worn, or if there's too much clearance between the valve stems and guides, or if the valve guide seals are worn, cracked, missing, broken or improperly installed, the engine will suck oil down the guides and into the cylinders. The engine may still have good compression, but will use a lot of oil.
Worn valve guides can usually be restored a number of different ways. One popular method machine shops use is to ream out the guides and install thin bronze or cast iron guide liners. Knurling is another procedure that can reduce valve guide clearances. With aluminum heads, the original guides can be driven out and replaced with new ones. With cast iron heads, the guides can be reamed out to accept new valves with oversized stems.If the oil burning is due to worn or broken rings, or wear in the cylinders, the engine will have low compression. The only cure here is to bore or hone the cylinders and replace the worn or broken piston rings
2. Engine bearing noise
The engine bearing in your vehicle refers to either the engine's main bearings or the rod bearings. Engine bearings protect and support the connecting rod or crankshaft, enabling it to spin freely in the engine. When there are problems with engine bearings, the vehicle will demonstrate a few tell tale symptoms that must be addressed sooner rather than later
Problems with engine bearings will usually result in some sort of knocking noise coming from your engine. The type of knocking noise that you hear will use the usually give you a good idea of which engine bearing is faulty or needs to be replaced.
Bad main bearing sounds. If you hear knocking sounds when you start your car that continue while the engine is running, and the sound is coupled with low oil pressure warnings, this is a good indicator that your engine has bad main bearings Faulty rod bearing sounds. If the knocking noise sounds more akin to striking a piece of tin or aluminum and increases in intensity as you accelerate, the most likely culprit is a faulty rod bearing
3. Piston Slap Noise
Piston slap on cylinder makes a sharp metallic noise. Idle engine and short out each cylinder plug. The noise will disappear when plug with bad piston is shorted. Noise will also disappear at acceleration. This can be caused by worn or out of round cylinder, or broken piston ring. Correct problem by re-boring cylinder and/or replacing piston.
Excessive piston slap occurs when the clearance between the piston and the cylinder bore is too great. The piston to cylinder bore clearance becomes too great either through wear, mismatched pistons and cylinder bores at manufacturing or, a combination of both. The audible noise associated with excessive piston slap is due to the perpendicular impact of the piston against the wall of the cylinder bore. Audible piston slap is typically loudest when the engine is first started up. The pistons then expand with heat reducing the piston to cylinder bore clearance thus, reducing the perpendicular impact of the piston against the cylinder wall and its resulting noise.
4. Excessive Fuel Consumption
Here are a few engine problems of more fuel consumption:
- missing or defective thermostat, causing low operating temperature - clogged intake manifold exhaust crossover passage (for heating intake manifold) - engine misfire caused by bad spark plug, ignition wire, coil, dist. cap or rotor - late ignition timing - bad vacuum advance unit (common in old cars) - stuck centrifugal advance mechanism in distributor (needs oil occasionally) - bad tension adjustment of centrifugal advance springs - defective oxygen sensor (causes rich mixture) - defective coolant temp. sensor for engine computer (causes rich mixture) - worn timing belt (may cause rich fuel mixture in fuel injected cars with a MAP sensor) - incorrect timing belt installation (timing marks should line up) - sticking or poorly adjusted carburetor choke (causes rich mixture) - dirty air filter on an engine with a carburetor (causes rich mixture at high power) - clogged or defective PCV valve - incorrect valve clearance (especially if too tight) - high performance camshaft installed (not efficient at low power) - worn valve guides (makes fuel mixture too lean at low power) - vacuum leak from bad vacuum hoses or intake system gaskets (causes lean mixture) - dirty fuel injectors - bad fuel pressure regulator - bad MAP sensor for fuel injection - leaking intake duct between air flow sensor and throttle body - too much alcohol in gasoline with old car (requires carb. modification for correct mixture) - rusted or missing exhaust heat stove or pipe for heated air intake - loss of compression pressure due to worn rings or leaking valves - sticking EGR valve (causes rough idling and rich mixture on some engines) - exhaust backpressure caused by clogged catalytic converter, muffler or crushed pipe - stuck exhaust manifold valve for some V type engines. Intended for fast warm up.
ENGINE OVERHAULING
The engine overhauling depends on the performance of the engine.
We may need an engine overhaul when we see one or more of the following indications-
Excessive engine oil consumption Engine bearing noise Piston slap noise Excessive fuel consumption
1. Excessive Fuel Consumption
Oil consumption depends primarily on two things: the valve guides and piston rings. If the valve guides are worn, or if there's too much clearance between the valve stems and guides, or if the valve guide seals are worn, cracked, missing, broken or improperly installed, the engine will suck oil down the guides and into the cylinders. The engine may still have good compression, but will use a lot of oil.
Worn valve guides can usually be restored a number of different ways. One popular method machine shops use is to ream out the guides and install thin bronze or cast iron guide liners. Knurling is another procedure that can reduce valve guide clearances. With aluminum heads, the original guides can be driven out and replaced with new ones. With cast iron heads, the guides can be reamed out to accept new valves with oversized stems.If the oil burning is due to worn or broken rings, or wear in the cylinders, the engine will have low compression. The only cure here is to bore or hone the cylinders and replace the worn or broken piston rings
2. Engine bearing noise
The engine bearing in your vehicle refers to either the engine's main bearings or the rod bearings. Engine bearings protect and support the connecting rod or crankshaft, enabling it to spin freely in the engine. When there are problems with engine bearings, the vehicle will demonstrate a few tell tale symptoms that must be addressed sooner rather than later
Problems with engine bearings will usually result in some sort of knocking noise coming from your engine. The type of knocking noise that you hear will use the usually give you a good idea of which engine bearing is faulty or needs to be replaced.
Bad main bearing sounds. If you hear knocking sounds when you start your car that continue while the engine is running, and the sound is coupled with low oil pressure warnings, this is a good indicator that your engine has bad main bearings Faulty rod bearing sounds. If the knocking noise sounds more akin to striking a piece of tin or aluminum and increases in intensity as you accelerate, the most likely culprit is a faulty rod bearing
3. Piston Slap Noise
Piston slap on cylinder makes a sharp metallic noise. Idle engine and short out each cylinder plug. The noise will disappear when plug with bad piston is shorted. Noise will also disappear at acceleration. This can be caused by worn or out of round cylinder, or broken piston ring. Correct problem by re-boring cylinder and/or replacing piston.
Excessive piston slap occurs when the clearance between the piston and the cylinder bore is too great. The piston to cylinder bore clearance becomes too great either through wear, mismatched pistons and cylinder bores at manufacturing or, a combination of both. The audible noise associated with excessive piston slap is due to the perpendicular impact of the piston against the wall of the cylinder bore. Audible piston slap is typically loudest when the engine is first started up. The pistons then expand with heat reducing the piston to cylinder bore clearance thus, reducing the perpendicular impact of the piston against the cylinder wall and its resulting noise.
4. Excessive Fuel Consumption
Here are a few engine problems of more fuel consumption:
- missing or defective thermostat, causing low operating temperature - clogged intake manifold exhaust crossover passage (for heating intake manifold) - engine misfire caused by bad spark plug, ignition wire, coil, dist. cap or rotor - late ignition timing - bad vacuum advance unit (common in old cars) - stuck centrifugal advance mechanism in distributor (needs oil occasionally) - bad tension adjustment of centrifugal advance springs - defective oxygen sensor (causes rich mixture) - defective coolant temp. sensor for engine computer (causes rich mixture) - worn timing belt (may cause rich fuel mixture in fuel injected cars with a MAP sensor) - incorrect timing belt installation (timing marks should line up) - sticking or poorly adjusted carburetor choke (causes rich mixture) - dirty air filter on an engine with a carburetor (causes rich mixture at high power) - clogged or defective PCV valve - incorrect valve clearance (especially if too tight) - high performance camshaft installed (not efficient at low power) - worn valve guides (makes fuel mixture too lean at low power) - vacuum leak from bad vacuum hoses or intake system gaskets (causes lean mixture) - dirty fuel injectors - bad fuel pressure regulator - bad MAP sensor for fuel injection - leaking intake duct between air flow sensor and throttle body - too much alcohol in gasoline with old car (requires carb. modification for correct mixture) - rusted or missing exhaust heat stove or pipe for heated air intake - loss of compression pressure due to worn rings or leaking valves - sticking EGR valve (causes rough idling and rich mixture on some engines) - exhaust backpressure caused by clogged catalytic converter, muffler or crushed pipe - stuck exhaust manifold valve for some V type engines. Intended for fast warm up.