Engine assembly

Before final cleaning

• Remove all sharp edges created by machining

• Clean all internal & external threads

Combustion chamberCrankshaft oil holes Top & bottom of cylindersOil pump gears

Chamfer top of bolt holesUse tap or die for restoring threads

Copyright 2003 Gary Lewis – Dave Capitolo

Engine assembly

Before final cleaning

• Check lifter bores for rust & burrs

• Check cam bores for burrs

Use glaze breaker if necessary

Could distort cam bearings if not deburred

Engine assembly

Final cleaning

• Only after all machining is done

• Use detergent hot tank

• Insufficient cleaning results in . . . Piston ring wearBearing wearValve stem wear

Engine assembly

Final cleaning

• Coat cylinders & decks with clean oil to prevent rust

• Coat valves, seats, & decks with clean oil

Engine assembly

Assembling cylinder heads

• Guides must be clean & lubricated

• Install valves with oil• Protect seals with plastic sleeve on valve

• Check cam rotation on OHC heads

Engine assembly

Installing core plugs

• Measure bore diameter to assure correct plugs

• Use deep plugs where possible• Coat outer edges for sealing

• Drive plug in slightly below block surface

Engine assembly

Sealing coolant, lubricants, & combustion

• Typical cooling system is 15 PSI @ 230°F

• Typical oil pressure range is 20-80 PSI

• Gasket must not restrict flow• Fire rings protect gasket material & cyl pressure

Engine assembly

Chemical sealers

• Sometimes used in place of gaskets

• Silicone sealers (RTV) are flexible & temp resistant

• Anaerobic sealers – Absence of air

Engine assembly

Head gaskets

• Metal-asbestos replaced with ceramic laminate

• Composite core copperGood compressibility, low compression, 60AA

• Composite core steelHeat resistant, high compression, 60AA

• Coated gasketsResin, polymer, better sealing of fluids

• MLS (Multi layer steel)For dissimilar metals, 15-20AA

Engine assembly

Head gaskets

• Stainless steel faceOn one side for high cylinder head temps,GM diesels

• Embossed steelImproved heat transfer, ridges provide crush for sealing, high compression, 30-50AA

• No-retorquePolymer coated, printed with silicone for low clamping force areas

Engine assembly

Gaskets

• Cork used on valve covers, lifter covers, oil pansStretches & shrinks

• Synthetic rubberCompressible, does not wick, resists heat

Engine assembly

Crankshaft seals

• Rope type seals must be fitted

• Lip type sealsLips face the oil

• Nitril & neoprene are common• Viton withstands loads & heat

Engine assembly

OHV assembly

• Only after sub-assemblies have been inspected

• Install core plugs • Install chamfered cam bearings

Engine assembly

OHV assembly

• Check cam for straightness• Check cam fit in bearings & scrape as needed

Cam must rotate freely• Blow all passages clear

Engine assembly

OHV assembly

• Grease cam to protect lobes & install cam

• Install oil galley plugs with sealer on outer edges

Engine assembly

OHV assembly

• Install rear main seal (two piece seal)

• Install main bearings• Install crankshaft & check clearance

Engine assembly

OHV assembly

• Oil all bearings & position thrust main cap

• Torque all main caps• Check crankshaft endplay

Engine assembly

OHV assembly

• Install thrust plate & timing set

• Check camshaft endplay

Engine assembly

OHV assembly

• Install piston assemblies

• Loctite & torque rod nuts

• Check rod side clearance

Engine assembly

OHV assembly

• Install oil pump & drive shaft• Verify cam timing at split overlap

• Install timing cover

Engine assembly

OHV assembly

• Install oil pan• Torque heads onto block

• Install rocker arms & pushrods• Adjust valves & test

Engine assembly

OHC assembly differences

• Balance shaft bearings• Crank & cam must be set to TDC before installation• Some timing covers are installed before head or pan• Timing belts and covers are installed last

Engine assembly

Sealing crankshafts

• Bearing clearance must not be excessive• Seal surfaces must be concentric with journals

Engine assembly

Sealing crankshafts

• Seals should be within .005” TIR of crank centerline

• Poor seal concentricity with main caps not centered

Engine assembly

Sealing crankshafts

• Seal surfaces must not have grooves

Engine assembly

Sealing crankshafts

• Rope type rear main seals• Coated with dry lubricant

• Do not oil • Fitted with round stock, same size as seal surface

on crankshaft

Engine assembly

Sealing crankshafts• Lip seal rear main

Sealer on outer edgeOil on sealing surfaceThin coat of sealer at rear of parting line

Engine assembly

Sealing crankshafts• Side seals on rear main

Installed with nail or soaked in oil

Engine assembly

Valve timing• Check service manual for timing marks• Confirm by checking split overlap• Dual pattern cams don’t have equal lift & duration

Engine assembly

Valve timing• Valve timing can be adjusted with keys & bushings

Engine assembly

Pistons & rings• End gap .003” per inch of cylinder bore• Hypereutectic pistons use twice as much• End gap is increased by filing• End gap increases .003” for each .001” bore increase

Engine assembly

Pistons & rings• Oil control expander, then rails

Stagger end gaps• Lower compression ring, then top

Stagger end gapsOil grooves & check for rotation

Engine assembly

Piston types• Cast aluminum – OEM pistons• Forged aluminum – Stronger & better heat dissipation • Hypereutectic – High silicon content

LighterGood wear characteristicsTighter clearances due to low expansion rateRequires more ring end gap

Engine assembly

Piston skirts• Slipper skirts – Cam ground

Clearance for counterweightsSteel struts help piston expand with pin

• Barrel shaped skirt– Largest diameter is in the center

• Full skirt– Used in longer stroke engines

Engine assembly

Before attaching heads to blocks• Surfaces clean and flat

• Alignment dowels installed

• Threads clean • Sharp edges de-burred

• Check gasket direction Do not use sealer on coated gaskets

• Look up torque specs & sequence

Engine assembly

Attaching heads to blocks

• Torque in sequence in 3 steps• Threads lubricated with oil or sealer

• TTY bolts may need to be replaced

Engine assembly

Rocker arms

• Check rocker shafts for correct direction• Check for correct offset of rocker arms

Engine assembly

Valve adjustment

Piston at TDC, compression• Non-hydraulic valve trains

Adjust valves that are closed & rotate engine

• Adjustable hydraulic valve trainsZero lash plus pre-loadCollapse lifter and set clearance

• Non-adjustable hydraulic valve trains

Torque to specs

Engine assembly

Pre-oiling

Install lifters• Push rod engine

Rotate oil pump with speed handle

• Crank driven oil pumpsPre-lubricator used to pre-oil engines

• Assemble oil pump with grease for priming

• Crank engine with no spark plugs, fuel, or ignition

Engine assembly

Run-in stand

• Oil pressure & circulation• Compression• Noises• Gaskets & seals • Lifter rotation