Disassemble 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 components.




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 for warping

      All the engine bearings must be inspected for scoring and wear

      A thin film of oil should be applied to the internal engine block surfaces to prevent rusting while the engine is apart.



Reassembly of the Engine


Once all of the parts have been inspected and cleaned be prepared to answer the following questions.

  1. Why is it necessary to deglaze the cylinders?
  2. How does the oil flow after it leaves the oil pump?
  3. What are the bolt torque specifications for your main bearings, connecting rod bearings and cylinder head bolts?
  4. Pinpoint and describe all the basic engine parts

a)     Connecting Rods

b)     Pistons

c)      Piston Pins

d)     Oil Pump

e)     Crankshaft

f)        Camshaft

g)     Timing Gears

h)      Cylinder Heads

i)        Intake and Exhaust Valves

j)        Combustion Chambers


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 the clearance.

      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


Cylinder Head Project


Leave your engine for now and get your cylinder head off the shelf.


Reinstall the Heads


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 arms.

        Properly adjust the rocker arms when that cylinder is on the compression stroke.

        Turn the engine over until all the rocker arms have been adjusted

        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.