Engine assembly
Before final cleaning
• Remove all sharp edges created by machining
Combustion chamber
Crankshaft oil holes
Top & bottom of cylinders
Oil pump gears
• Clean all internal & external threads
Chamfer top of bolt holes
Use tap or die for restoring threads
Copyright 2003 Gary Lewis – Dave Capitolo
Engine assembly
Before final cleaning
• Check lifter bores for rust & burrs
Use glaze breaker if necessary
• Check cam bores for burrs
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 wear
Bearing wear
Valve 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 copper
Good compressibility, low compression, 60AA
• Composite core steel
Heat resistant, high compression, 60AA
• Coated gaskets
Resin, polymer, better sealing of fluids
• MLS (Multi layer steel)
For dissimilar metals, 15-20AA
Engine assembly
Head gaskets
• Stainless steel face
On one side for high cylinder head temps,
GM diesels
• Embossed steel
Improved heat transfer, ridges provide crush
for sealing, high compression, 30-50AA
• No-retorque
Polymer coated, printed with silicone for
low clamping force areas
Engine assembly
Gaskets
• Cork used on valve covers, lifter covers, oil pans
Stretches & shrinks
• Synthetic rubber
Compressible, does not wick, resists heat
Engine assembly
Crankshaft seals
• Rope type seals must be fitted
• Lip type seals
Lips 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
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Install oil pan
Torque heads onto block
Install rocker arms & pushrods
Adjust valves & test
Engine assembly
OHC assembly differences
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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 edge
Oil on sealing surface
Thin 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 gaps
Oil grooves & check for rotation
Engine assembly
Piston types
• Cast aluminum – OEM pistons
• Forged aluminum – Stronger & better heat dissipation
• Hypereutectic – High silicon content
Lighter
Good wear characteristics
Tighter clearances due to low expansion rate
Requires more ring end gap
Engine assembly
Piston skirts
• Slipper skirts – Cam ground
Clearance for counterweights
Steel struts help piston expand with pin
• Full skirt– Used in longer stroke engines
• Barrel shaped skirt– Largest diameter is in the center
Engine assembly
Before attaching heads to blocks
• Surfaces clean and flat
• Threads clean
• Sharp edges de-burred
• Alignment dowels installed
• Check gasket direction
Do not use sealer on coated gaskets
• Look up torque specs & sequence
Engine assembly
Attaching heads to blocks
• Threads lubricated with oil or sealer
• Torque in sequence in 3 steps
• TTY bolts may need to be replaced
Engine assembly
Rocker arms
• Check for correct offset of rocker arms
• Check rocker shafts for correct direction
Engine assembly
Valve adjustment
• Non-hydraulic valve trains
Piston at TDC, compression
Adjust valves that are closed & rotate engine
• Adjustable hydraulic valve trains
Zero lash plus pre-load
Collapse lifter and set clearance
• Non-adjustable hydraulic valve trains
Torque to specs
Engine assembly
Pre-oiling
• Push rod engine
Install lifters
Rotate oil pump with speed handle
• Crank driven oil pumps
Pre-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
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Oil pressure & circulation
Compression
Noises
Gaskets & seals
Lifter rotation