Modern Automotive Technology PowerPoint for by Russell Krick Publisher The Goodheart-Willcox Co., Inc. Tinley Park, Illinois

Chapter 52 Engine Front End Service and Engine Installation

Contents Timing chain service Timing gear service Crankshaft front seal service Engine front cover service Timing belt service Complete engine assembly Installing the engine Engine break-in

Timing Chain Service Timing chains can be used on both push rod and overhead cam engines Inspect the chain for looseness Check the crankshaft key and camshaft dowel for wear or damage If used, check the chain tensioner and guides for wear

V-type, diesel engine with a timing chain Front End Assembly V-type, diesel engine with a timing chain

OHC Timing Chain Uses a tensioner to compensate for chain wear or stretch Chain guides prevent vibration, or slap Fiber or plastic facings on guides and tensioner may wear

OHC Timing Chain

Installing Timing Chain Align the marks on the sprockets to time the crankshaft with the camshaft

Installing Timing Chain Install the oil slinger after the sprocket It sprays oil on the chain and sprockets

Installing Timing Chain When installing complex OHC timing chains, double- check everything

Timing Gear Service Timing gears are normally more dependable than timing chains However, gear teeth can wear or become chipped and damaged Replace gears as a set, if needed

Measuring Backlash Backlash is the amount of clearance between the timing gear teeth To measure: install a dial indicator with the stem on a cam gear tooth wiggle the camshaft, while watching the indicator the needle movement equals the backlash Replace the timing gears if the backlash is greater than specs

Measuring Backlash (Dial Indicator and Feeler Gauge) The largest feeler gauge that fits in the teeth indicates clearance

Replacing Timing Gears Gears may be press-fit on the crankshaft and camshaft A puller is normally needed to remove the crankshaft gear Gears can often be installed with light blows from a brass hammer

Replacing Timing Gears Some camshaft gears must be pressed on and off after removal from the engine

Timing marks on a diesel engine Timing Gear Alignment Timing marks on a diesel engine

Measuring Gear Runout Runout is unwanted gear wobble, or side movement To measure: install a dial indicator with the stem on the outer edge of the cam gear turn the crankshaft while noting the indicator readings the needle movement equals the runout

If the runout is beyond specs, check the cause Measuring Gear Runout If the runout is beyond specs, check the cause

Crankshaft Front Seal Service Replace the front seal whenever it is leaking or anytime the front cover is removed Seal replacement usually requires the removal of the radiator, other accessory units, and the crankshaft damper

Removing Crankshaft Damper

A special puller is often used Removing the Old Seal A special puller is often used

Installing the New Seal Before installing, oil the lip and coat the outside with nonhardening sealer

Engine Front Cover Service Front covers are usually made of thin sheet metal or cast aluminum Make sure a sheet metal cover is not warped

Typical parts included Front Cover Gasket Set Typical parts included

Installing the Gasket Coat the cover flange or gasket with an approved adhesive-sealer to hold it in place

Using Silicone Sealer Apply sealer in the specified thickness Surround the bolt holes and water passages

Removing Old Gaskets If you are servicing the front cover only, cut off the old gasket and clean the surfaces

Surface Preparations Extra silicone sealer is recommended where the front cover meets the oil pan A small piece of pan gasket can be placed on the protruding oil pan flange

Installing the Front Cover Carefully fit the front cover into place without disturbing the gasket or silicone sealer With some designs, you must loosen the oil pan bolts and partially drop the pan

Installing the Front Cover An alignment tool may be used Remove the tool after installation

Front Cover Installation Bolt lengths differ, and one bolt requires sealer because it enters the water jacket

Timing Belt Service Many OHC engines use a synthetic rubber belt to operate the camshaft Cogged belts are accurate, quiet, light, and dependable Belt service is important a broken or improperly timed belt could cause major engine damage

Timing Belt Assembly

Inspecting the Timing Belt Inspect the belt for cracks, softening, and fraying Most manufacturers recommend replacement at intervals of 50,000–100,000 miles (80,000–160,000 km)

Timing Belt Problems

Inspecting the Belt Tensioner Always check the belt tensioner bearings

Removing a Timing Belt Sprocket When reinstalling, align any key or dowel that positions the sprocket

Installing the Timing Belt This camshaft sprocket mark is aligned with the belt marking and the timing mark on the engine

Installing the Timing Belt Align the dowel with the timing pointer on the engine

Installing the Timing Belt Slip the belt on and move the tensioner into the belt

Adjusting Belt Tension Proper timing belt tension is very important to the belt’s service life If it is too tight, it can wear out quickly or break If it is too loose, the belt can flap, vibrate, or fly off

Adjusting Belt Tension A pry bar may be used to adjust the tensioner

Adjusting Belt Tension Moderate finger and thumb pressure should be needed to twist the belt

Installing the Timing Belt Cover Tighten the fasteners to specs

Complete Engine Assembly To complete the engine rebuild, install all remaining parts that do not prevent engine installation: sensors and wiring sending units brackets motor mounts heat shrouds

Complete Engine Spark plug wires and some hoses may be installed prior to engine installation

Installing the Engine Safety rules to remember: keep your hands and feet out from under the engine never work on an engine raised on a hoist never move the hoist when the engine is raised high in the air—the hoist could flip over

Installation Steps On automatic transmission-equipped vehicles: rotate the engine so the large hole in the flywheel faces down rotate the torque converter so the drain plug is down for easy alignment On manual transmission-equipped vehicles: check the condition of the pilot bearing

Installation Steps Position the lifting chain so the engine is raised in a level position Slowly lower the engine into the vehicle while watching for clearance all around Align the engine dowel pins with the holes in the transmission Push the engine into the transmission so the dowel pins are fully seated

Installation Steps Start the bell housing bolts by hand Check the torque converter or clutch alignment and install any bolts Tighten the bell housing bolts Finish installing the other components: motor mounts fuel lines, hoses, linkages, and wires

Installation Steps Accessories and components for installation after the engine is in place

Starting the Engine After installation: fill the engine with oil and the radiator with coolant start the engine and run it at fast idle until warm, while watching the oil pressure perform any final adjustments check for any fluid leaks

Engine Break-In Done mainly to seat new piston rings Typical procedures: after warm-up, road test the vehicle, using moderate acceleration and deceleration accelerate to about 40 mph (65 km/h) coast down to about 20 mph (32 km/h), with a closed throttle repeat several times while monitoring the oil pressure and coolant temperature

Brief the Owner Brief the owner about good break-in driving habits: avoid prolonged highway driving for the first 100–200 miles (161–322 km) don’t worry about oil consumption until after the first 2000 miles (3220 km) check the oil and other fluids frequently change the oil and filter after 2000 miles (3220 km)