GATE 4

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Complexity Scale

Complexity: 1

  • Single Piece with minimal manufacturing processes requiring no assembly. Size is, in this case, irrelevant to the complexity scale. In this case finishing might be extensive but accuracy is low.

Complexity: 2

  • Single piece with extensive machining and finishing required. In this case, the part is detailed with attention to weight, balance and other specific details. Higher accuracy is required in this case.

Complexity: 3

  • Assembly with few parts which can be assembled entirely by automation. In most cases the part is small. Size is small.

Complexity: 4

  • Assembly with more parts that requires either machining and/or assembly by hand.

Complexity: 5

  • Assembly with many parts that require both machining and assembly by hand. In this case, size is larger than levels 3 or 4.

Reassembly Procedure


1. The first step is to re-insert the crankshaft in the engine block.

  • Complexity: 2 (large heavy part which requires considerable strength to place).


2. The crankshaft bearings were then bolted back on to hold the crankshaft in place.

  • 4 bearings and retainers with two 16mm bolts each.
  • Complexity: 1 (to substantial effort required and few fasteners).


3. The engine was turned over and the pistons were pushed into the engine block.

  • Due to a lack of a piston ring compressor, the technical experts used screwdrivers to push rings in.
  • There was damage to the piston rings; however, it is unclear whether it was pre-existing or if was caused by the team.
  • This particular step was different form the removal of the pistons as it was important that the pistons were not re-inserted at an angle. If it were, the connecting arms and the camshaft would not fit together without being tapped to the correct 90 degree angle. This would be undesirable as it is difficult to turn the pistons once they are inside the cylinders.
  • The insertions of all the pistons were not done all at once. The whole block was flipped over twice to ensure that the pistons did not slide back out and the pistons were inserted 3 at a time. The bearings and clamps had to be fitted back on before it could be flipped over and after they were flipped over.
  • Complexity: 4 (there were only eight fasteners but the bearings were difficult to insert between the retainers. Furthermore, the pistons themselves required three people to insert into their cylinders given that specialized tools were unavailable).


4. The oiler was then replaced into the bearings.

  • Complexity: 2 (large single piece with minimum effort required).


5. The camshaft was replaced into its bearings. The mounting bracket was then bolted on with Torx head screws.

  • One of the design improvements would certainly include converting these to Philips head screws.
  • Complexity: 2 (some specialized tools are required).


6. The timing gear, oiler drive gear and the timing chain were re-attached.

  • Complexity: 3 (large parts with some difficulty in re-attachment).


7. The flywheel was attached.

  • Complexity: 3 (problems were faced when holding up the and aligning the flywheel's six 14mm bolts).


8. The oil filter was re-attached.

  • Complexity: 1 (one 16mm bolt).


9. The engine was then turned over and then the oil pan and oil cooler were re-attached.

  • Complexity: 1 (eight 13mm bolts).


10. The lifters were placed in contact with the camshaft.

  • Complexity: 1 (12 lifters were placed in the accommodating grooves).


11. The lifter covers and their bolts were bolted on.

  • Complexity: 1 (2 lifter covers each with two 10mm bolts).


12. The cylinder heads were replaced.

  • Complexity: 4 (significantly heavy with 16, 13mm bolts. More than 1 person required to place and tighten bolts).


13. The pushrods were then dropped in place.

  • Complexity: 3 (rockers had to be loosened to allow the rods to slide into their shafts).


14. The rockers were then bolted on.

  • Complexity: 3 (rockers had to be removed in order to insert the pushrods).


15. The camshaft sprocket and timing chain cover were replaced.

  • Complexity: 2 (only 6 bolts).


16. The harmonic balancer was the replaced and the crank pulley was attached to it.

  • Complexity: 4 (the harmonic balancer had to be hammered back into place).


17. The water pump was bolted back on.

  • Complexity: 22 (an additional person had was needed to hold up the pump as it was bolted back in).


18. The intake manifold was re-attached to the engine block.

  • Complexity: 3 (the part itself is heayvy but once in the engine block, it was easy to shift into position and bolt on).


19. The cylinder head covers were then bolted back on.

  • Complexity: 1.


20. The fuel injector was replaced on the intake manifold and the lines re-connected to the respective ports.

  • Complexity: 2 (the ports are numbered and can be inserted by hand).


21. The exhaust manifolds were bolted back on.

  • Complexity: 2 (ten 14mm bolts and 2 gaskets were used with each manifold. Only 2 gaskets were found, it is assumed that the other 2 were missing).


22. The upper intake manifold and the distributor was re-attached.

  • Complexity: 2 (six 12mm bolts were used to re-attached the manifold).


23. Finally, the throttle body was re-attached.

  • Complexity: 1 (three 10mm bolts were used).



Additional Notes On Gate 4


On the whole, the reassembly procedure mirrored the assembly procedure. The only parts that could be removed or inserted at any time were the oil pan, oil filter and exhaust manifolds as they were easily accessible and located on the exterior of the engine block. The product was not usable when we obtained it for the dissection process because tt is a component of a car. Despite this, the crankshaft was somewhat harder to turn after reassembly. This problem was attributed to a lack of lubrication. It can be easily remedied with conventional motor oil. There were also 2 missing bolts and 2 missing exhaust manifold gaskets.

In terms of ergonomics, a few design changes are recommended. One improvement that we would recommend is that the bolt sizes be kept more uniform (i.e. a lesser variation in variety of wrench sockets that are required). Also, the Torx head screws on the mounting bearing for the camshaft be replaced with more functional and conventional Philips head screws.

The differences in the assembly and reassembly are apparent only in steps 3, 13 and 14. There was also little difference in tools; the harmonic balancer required a pulley puller to remove.