and Reassemble a 4 Cycle Engine
Before you start this project make sure you have
cleared a shelf for engine parts and you have a clean box or metal can to hold
all your assembly hardware. You do not want to loose all the bolts and small
- Drain all fluids from the engine. Coolant and motor oil
- Remove the intake and exhaust manifolds from the cylinder heads.
- Remove drive belts, water pump and vibration damper.
- Remove the ignition distributor if installed
- Remove the rocker / valve covers
- Remove the rocker arms, ball pivots, pushrods and lifters
- Remove all the cylinder head bolts and put them is a safe place
- Remove the cylinder heads - the head can be heavy, get a
- Put the cylinder head on a shelf for more work later
- Check the cylinder walls and check for a ridge at the top of the
- Ream the ridge off the cylinder with the ridge reamer
- Study how the timing gears align then remove the timing gears.
- Remove the camshaft front support bearing and the camshaft
- Turn the motor upside down now if possible
- Remove the engine oil pan.
- Remove the oil pump and sump assembly
- Check to see if all the connecting rod caps and main bearings caps
have been numbered from the factory. If not - number them.
- Study how the connecting rod caps align with the connecting rods
- Remove ONE connecting rod and piston at a time and store in a safe
- Immediately reinstall the connecting rod cap on the connecting rod
- This procedure prevents damage.
- Continue until all the pistons and connecting rods have been
- Remove the main bearing caps one at a time starting from the ends
and working towards the centre.
- If you are doing an engine that has a transmission attached to it -
leave the centre main bearing cap installed!
- Clean and inspect all the engine parts for wear and damage.
Now that the engine is
disassembled you must perform several tasks before it can go back together.
You must deglaze the cylinders and investigate why
this must be done
All the gasket surfaces must be cleaned and checked
All the engine bearings must be inspected for scoring
A thin film of oil should be applied to the internal
engine block surfaces to prevent rusting while the engine is apart.
of the Engine
Once all of the parts have been inspected and cleaned
be prepared to answer the following questions.
- Why is it necessary to deglaze the cylinders?
- How does the oil flow after it leaves the oil pump?
- What are the bolt torque specifications for your main bearings,
connecting rod bearings and cylinder head bolts?
- Pinpoint and describe all the basic engine parts
Intake and Exhaust Valves
When the above section is complete and your
instructor has given you permission to reassemble your engine begin doing so.
Reinstall all the main bearing caps and PLASTIGAGE
With the piston ring compressor, reinstall all the
pistons into the correct cylinders.
Plastigage all the
connecting rod bearings too.
Make sure that you have torqued all the bearing caps
to the correct torque values
Reinstall the camshaft and timing gears correctly -- TIMED.
Make sure the engine can still spin freely.
Install your timing cover and oil pan
Leave your engine for now and get your cylinder head
off the shelf.
- Clean your cylinder heads and gasket surfaces
- Using the valve spring compressor, remove the valve keepers and
- Make sure you number all your valves because they must be
reinstalled into the same valve guides.
- When all the valves have been removed clean all the carbon deposits
off of them with the wire wheel.
- Inspect all the valves for wear and burning.
- If possible, clean the intake and exhaust ports with a polishing
- Install the valves in the correct guides and with the use of valve
grinding compound, clean the face to seat surfaces.
- When all the cylinder head parts are clean and inspected it is time
- Reverse the process and install the valves with the valve spring
Install the cylinder heads onto the block and torque
the head bolts to the correct torque value. The proper torque pattern must be
followed while bolting the heads to the block.
This is usually a circular pattern starting from the
centre head bolts.
Reinstall the valve lifters, pushrods and rocker
Properly adjust the rocker arms when that cylinder is
on the compression stroke.
Turn the engine over until all the rocker arms have
Reinstall the rocker covers
Reinstall the exhaust and intake manifolds with your
self-made intake manifold gaskets.
Have your instructor inspect your totally assembled
engine for missing parts and operation.