© © 2012 Delmar, Cengage Learning

Engine Removal and Disassembly

Chapter 50

© © 2012 Delmar, Cengage Learning

Objectives• Label and organize parts prior to engine

removal• Remove an engine from a vehicle in a safe and

methodical manner• Disassemble the engine following the correct

procedures• Keep parts organized for reassembly• Inspect and interpret causes internal engine

wear

© © 2012 Delmar, Cengage Learning

Introduction• Procedures must be followed carefully

– Parts must be removed and inspected in an orderly manner

• You cannot hurry• Signs of wear can be clues• Correct repair will prevent the problem from

occurring again

– Be sure to consult the applicable repair manual• Procedures differ

© © 2012 Delmar, Cengage Learning

Engine Removal• Important steps

– Disconnect battery cables

– Remove the hood

– Remove air cleaner

– Label all wires and vacuum lines

– Drain coolant and oil

– Remove the radiator

– Remove the distributor and spark plug wiring

– Remove the direct current (DC) generator

– Remove the heater hoses and ground strap

© © 2012 Delmar, Cengage Learning

© © 2012 Delmar, Cengage Learning

© © 2012 Delmar, Cengage Learning

Engine Removal (cont'd.)– Remove switches and sensors

– Remove the throttle linkage, cable, or wiring

– Mark accessory brackets and remove accessories

– Remove exhaust components

– Remove and plug the fuel line

– Determine whether to remove the transmission

– Separate the engine and transmission/transaxle

– Unbolt the engine mounts

© © 2012 Delmar, Cengage Learning

© © 2012 Delmar, Cengage Learning

Engine Removal (cont'd.)– Remove the engine from the vehicle

– Remove transaxle (if necessary)• Remove lower ball joints

– Have drain pan ready

• Disconnect speedometer cable, transmission shift linkage, and clutch cable

• Attach a sling to the engine and transaxle assembly• Remove bolts• Roll shop crane until the engine can be lowered

safely

© © 2012 Delmar, Cengage Learning

Engine Disassembly• Important steps

– Remove clutch parts

– Remove hybrid armature (puller required)

– Mount engine to a stand

– Remove coolant pump

– Remove oil pan

– Remove valve covers• Slip a knife blade between head and sheet metal

valve cover• Tap a curved, strong area with a rubber mallet

© © 2012 Delmar, Cengage Learning

Engines with Pushrods• Stud mounted rockers

– Loosen nuts on studs before disassembly and cleaning

– Turn rocker arms to the side to remove the pushrods

– After heads are cleaned they can be removed one at a time

– Keep pushrods in order

© © 2012 Delmar, Cengage Learning

Engines with Pushrods (cont'd.)• Shaft-mounted rockers

– Should be loosened slowly and evenly

– Remove the pushrods

– Pushrods can be pushed through holes made in a piece of cardboard

– Pushrods must be kept in order

© © 2012 Delmar, Cengage Learning

Engines with Pushrods (cont'd.)• Valve lifters

– Remove valve lifters

– Wipe oil off bottom of lifters

– Label with a felt marker

– Reused flat tappers must be used on original cam lobe

• Usually replaced

– Roller lifters are usually reusable

– Use chemical cleaner to soften varnish

© © 2012 Delmar, Cengage Learning

© © 2012 Delmar, Cengage Learning

© © 2012 Delmar, Cengage Learning

Engines with Pushrods (cont'd.)• Pushrod engine camshaft

– Some pushrod engines use bolt-on cam thrust plate

– Varnish may builds up on edges of cam journals• Makes it difficult to remove the cam

• Vibration damper removal– Most engines have a bolt that holds it on the

crankshaft• Some will slip off after the bolt is removed

– Others are pressed-fit

© © 2012 Delmar, Cengage Learning

Overhead Cam Cylinder HeadRemoval

• Important steps– Position the number one piston at TDC and note

the location of timing marks

– Compare the sketch in the repair manual to the marks on the timing belt

– Draw a sketch of the cam timing

– Remove timing cover

© © 2012 Delmar, Cengage Learning

© © 2012 Delmar, Cengage Learning

Overhead Cam Engines (cont'd.)

– Remove the cam drive assembly• Pushrod engines

– Unbolt cam sprocket and slide or pry off the cam– Remove the chain– Reinstall sprocket and tighten one bolt finger tight

• Overhead cam engines– Remove the chain or bolt tensioner

© © 2012 Delmar, Cengage Learning

© © 2012 Delmar, Cengage Learning

Overhead Cam Engines (cont'd.)

– Remove the cylinder heads• Mark one of the cylinder heads “left” or “right” if

there is more than one• Be careful not to break a casting

– Inspect the head gasket• Evidence of coolant or oil leakage• Signs of detonation

© © 2012 Delmar, Cengage Learning

Cylinder Block Disassembly• Modern engines use premium piston rings

– Will not accommodate a worn cylinder bore

• Ridge causes– Pressure of combustion forcing the piston ring

against the cylinder wall

– Lack of clean lubrication at the top of the cylinder

© © 2012 Delmar, Cengage Learning

Cylinder Block Disassembly (cont'd.)

• Important steps– Turn engine over and mark main caps and rod

caps

– Main caps must be installed in one direction only

– Connecting rods and caps are mated to one another and must be marked for identification

– Remove and inspect the piston and rod assembly

– Inspect the piston, rings, rod, and bearings

– Remove the crankshaft and inspect for wear

– Remove the camshaft

© © 2012 Delmar, Cengage Learning

© © 2012 Delmar, Cengage Learning

Cylinder Block Disassembly (cont'd.)

– Remove and label cam bearings

– Remove core plugs

– Clean engine parts

– Remove the crank sprocket or gear

– Finish diagnosis and repair of engine assembly