Halderman ch028 lecture

© 2011 Pearson Education, Inc.All Rights Reserved

Automotive Technology, Fourth EditionJames Halderman

ENGINE REMOVAL AND DISASSEMBLY

28

28 ENGINE REMOVAL AND DISASSEMBLY



ObjectivesObjectives• The student should be able to:

– Prepare for ASE Engine Repair (A1) certification test content areas “B” (Cylinder Head and Valve Train Diagnosis and Repair) and “C” (Engine Block Diagnosis and Repair).

– Explain the differences between a long block and a short block assembly.

– Describe how to remove an engine from a vehicle.




ObjectivesObjectives• The student should be able to:

– Explain how to remove engine accessory components, such as the covers and valve train components.

– Discuss how to remove cylinder heads without causing warpage.

– List the steps necessary to remove a piston from a cylinder.

– Explain how to remove a valve from a cylinder head.




ENGINE REPAIR ENGINE REPAIR OPTIONSOPTIONS




Engine Repair OptionsEngine Repair Options• Technician and Owner Decision

– Engine might not be worth repairing– Customer must make decision based on

technician’s recommendation




Engine Repair OptionsEngine Repair Options• Repair Options

– Types of component repairs• Component replacement• Valve job• Minor overhaul





– Types of component repairs• Major overhaul• Short block• Long block





– Types of component repairs• Crate engines• Remanufactured engines




Figure 28-1 A worn timing sprocket that resulted in a retarded valve timing and reduced engine performance.




Figure 28-2 A crate engine from Chrysler to be used in a restored muscle car. Using a complete new engine costs more than rebuilding an existing engine, but it has a warranty and uses all new parts.




ENGINE REMOVALENGINE REMOVAL




Engine RemovalEngine Removal• Check Service Information

– Print out specified procedure as published in service information




Engine RemovalEngine Removal• Usual Engine Removal Procedures

– Remove hood– Clean engine area– Disconnect negative (−) battery cable, and

remove battery





– Remove air cleaner assembly– Remove all accessories– Drain coolant– Remove radiator





– Disconnect exhaust system– Recover air-conditioning refrigerant– Remove power steering pump





– Drain engine oil– Disconnect fuel lines– Disconnect wiring and vacuum hoses




Engine RemovalEngine Removal• Procedure for Engine Removal

– Two ways to remove engine• Lifted out of chassis with

transmission/transaxle attached





– Two ways to remove engine• Transmission/transaxle separated from

engine and left in chassis





– Removal procedure for most rear-wheel-drive vehicles

• Under vehicle, remove driveshaft and disconnect exhaust pipes






• Remove the engine mounts






• Disconnect transmission controls and wiring at connectors






• Disconnect and label clutch linkages






• Attach sling to lifting hooks, intake manifold, or cylinder head bolts






• Remove rear cross-member and lower transmission






• Tip front of engine






• Hoist engine and transmission




Figure 28-3 An engine must be tipped as it is pulled from the chassis.





– Removal procedure for most front-wheel-drive vehicles

• Swing clear and place on floor






• Can be removed from top or from underneath






• Disconnect units that might interfere with engine removal

– Steering unit, engine electrical harness, radiator






• If removing from underneath, remove upper strut and lower engine cradle fasteners






• Disconnect torque converter, bell housing bolts, clutch linkage






• Use holding fixtures to hold transaxle in place during removal




Figure 28-4 When removing just the engine from a front-wheeldrive vehicle, the transaxle must be supported. Shown here is a typical fixture that can be used to hold the engine if the transaxle is removed or to hold the transaxle if the engine is removed.




Figure 28-5 The entire cradle, which included the engine, transaxle, and steering gear, was removed and placed onto a stand. The rear cylinder head has been removed to check for the root cause of a coolant leak.




ENGINE DISASSEMBLYENGINE DISASSEMBLY




Engine DisassemblyEngine Disassembly• Mounting the Engine on a Stand

– Use at least four grade 8 bolts when mounting engine to stand

– Ensure that proper threads of bolts being used




Engine DisassemblyEngine Disassembly• Mounting the Engine on a Stand

– Bolts must have at least 1/2 in. (13 mm) of thread engaged in engine

– Engine properly balanced on stand




Figure 28-6 Always use graded bolts—either grade 5 or 8 bolts—whenever mounting an engine to a stand.




Engine DisassemblyEngine Disassembly• Disassembling a Cam-in-Block (OHV)

Engine– Should be cold before disassembly– Remove rocker arm covers; inspect rocker

arms, valve springs, valve tips





Engine– Remove rocker arms and pushrods– Remove intake manifold bolts and lift off

manifold





Engine– Remove lifters– Remove cylinder head bolts– Carefully lift head from block deck





Engine– Inspect combustion chamber in head and

top of piston– Check cylinder head and head gasket for

signs of leakage




Figure 28-7 Keeping the pushrods and the lifters sorted by cylinder, including the spark plugs, is a wise way to proceed when disassembling the cylinder heads.




Figure 28-8 Sometimes after the cylinder head has been removed, the engine condition is discovered to be so major that the entire engine may need to be replaced rather than overhauled.




Engine DisassemblyEngine Disassembly• Overhead Cam Shaft (OHC) Engine

Disassembly– Remove intake and exhaust manifolds– Remove crankshaft harmonic balancer

pulley





Disassembly– Remove timing belt cover and timing belt– Remove camshaft(s) before removing

cylinder head





Disassembly– Remove cylinder head by removing

cylinder head bolts – Carefully lift cylinder head from block




DISASSEMBLY DISASSEMBLY OF THE SHORT BLOCKOF THE SHORT BLOCK




Disassembly of the Short BlockDisassembly of the Short Block• Removing the Oil Pan

– Turn engine upside down to remove– Inspect pan and oil pump pickup screen




Disassembly of the Short BlockDisassembly of the Short Block• Marking Connecting Rods and Caps

– Number so can be reassembled in exact same position

– Mark with number stamp, electric pencil, or permanent marker




Figure 28-9 These connecting rods were numbered from the factory. If they are not, then they should be marked.




Disassembly of the Short BlockDisassembly of the Short Block• Removing the Cylinder Ridge

– Remove cylinder ridge before pistons can be removed from block

– Necessary to avoid catching ring on ridge and breaking piston

– Use cutting tool with guide to prevent accidental cutting below ridge




Figure 28-10 Most of the cylinder wear is on the top inch just below the cylinder ridge. This wear is due to the heat and combustion pressures that occur when the piston is near the top of the cylinder.




Figure 28-11 This ridge is being removed with one type of ridge reamer before the piston assemblies are removed from the engine.




Disassembly of the Short BlockDisassembly of the Short Block• Piston Removal

– Rotate engine until piston to be removed at bottom dead center (BDC)

– Remove connecting rod nuts from rod so rod cap can be removed




Disassembly of the Short BlockDisassembly of the Short Block• Piston Removal

– Fit rod bolts with protectors, then remove piston and rod assemblies

– After removal of each piston, replace rod cap and nuts




ROTATING ENGINEROTATING ENGINEASSEMBLIES REMOVALASSEMBLIES REMOVAL




Rotating Engines Assembly RemovalRotating Engines Assembly Removal• Harmonic Balancer Removal

– Remove crankshaft vibration damper (also called harmonic balancer)

– Remove bolt and washer that hold damper





– Remove damper only with a threaded puller

– Remove timing cover, exposing timing gear (or chain)





– Inspect parts for excessive wear or looseness

– Remove bolted cam sprockets to free timing chain





– May require removal of crankshaft gear at same time

– Gears and sprockets removed from shaft only if faulty




Figure 28-12 Puller being used to pull the vibration damper from the crankshaft.




Figure 28-13 When the timing chain cover was removed, the broken timing gear explained why this GM 4.3 liter V-6 engine stopped running.




Rotating Engines Assembly RemovalRotating Engines Assembly Removal• Camshaft Removal

– Insert long bolt into a camshaft threaded hole as handle for removing

– Carefully ease camshaft from engine with front of engine pointing up




Rotating Engines Assembly RemovalRotating Engines Assembly Removal• Crankshaft and Main Bearing Removal

– Check main bearing caps for position markings, or mark them

– Remove caps; then remove crankshaft– Reinstall caps and bearings on block to

reduce chance of damage




Figure 28-14 Most engines such as this Chevrolet V-8 with four-bolt main bearing caps have arrows marked on the bearing caps which should point to the front of the engine.




Rotating Engines Assembly RemovalRotating Engines Assembly Removal• Block Inspection

– After pistons and crankshaft removed, remove cups and plugs

– Inspect block for faults that could affect whether engine can be rebuilt




Figure 28-15 This small block Chevrolet V-8 had water standing in the cylinders, causing a lot of rust, which was discovered as soon as the head was removed.




CYLINDER HEAD CYLINDER HEAD DISASSEMBLYDISASSEMBLY




Cylinder Head DisassemblyCylinder Head Disassembly• OHV Engine Cylinder Heads

– Tap valve spring retainer with brass hammer on an angle

– Compress valve spring far enough to expose keepers





– Use magnet to remove keepers– Slowly release valve spring compressor and

remove





– Lightly file valve tip edge and keeper area to remove burrs before sliding valve from head





– Remove valve stem seals and metal spring seats used on aluminum heads

– Carefully inspect valve springs, retainers, keepers, guides, seats




Figure 28-16 A torch is used to heat gallery plugs. Paraffin wax is then applied and allowed to flow around the threads. This procedure results in easier removal of the plugs and other threaded fasteners that cannot otherwise be loosened.




Figure 28-17 A valve spring compressor is used to compress the valve spring before removing the keepers (locks).




Cylinder Head DisassemblyCylinder Head Disassembly• OHC Engine Cylinder Heads

– After heads removed, remove camshaft and then valves

– Special valve spring compressor may be needed to reach valve retainers




ENGINE REMOVAL 1 Before beginning work on removing the engine, mark and remove the hood and place it in a safe location.




ENGINE REMOVAL 2 For safety, remove the negative battery cable to avoid any possible electrical problems from occurring.




ENGINE REMOVAL 3 Drain the coolant and dispose of properly.




ENGINE REMOVAL 4 Disconnect all cooling system and heater hoses and remove the radiator.




ENGINE REMOVAL 5 Remove the accessory drive belt(s) and set the alternator, power steering pump, and air conditioning compressor aside.




ENGINE REMOVAL 6 Remove the air intake system including the air filter housing as needed.




ENGINE REMOVAL 7 Remove the electrical connector from all sensors and label.




ENGINE REMOVAL 8 Disconnect the engine wiring harness connector at the bulkhead.




ENGINE REMOVAL 9 Safely hoist the vehicle and disconnect the exhaust system from the exhaust manifolds.




ENGINE REMOVAL 10 Mark and then remove the fasteners connecting the flex plate to the torque converter.




ENGINE REMOVAL 11 Lower the vehicle and remove the engine mount bolts and transaxle bell housing fasteners.




ENGINE REMOVAL 12 Secure the lifting chain to the engine hooks and carefully remove the engine from the vehicle.

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Halderman ch028 lecture