Materials and Manufacturing Processes





McLaren MP4-12C Engine



Dismantling the cylinder head of the McLaren MP4-12C engine and analysing the materials and manufacturing processes used



KEY SKILLS





Materials Analysis



Manufacturing Processes



Teamwork



OVERVIEW





BRIEF



Conducted a group lab to dismantle the cylinder head of the McLaren engine and to outline the fundamentals, with particular focus upon the materials and manufacturing processes of 5 components.



DELIVERABLES



  • 14 page group report


SOLUTION



The project was an excellent introduction to the materials and manufacturing processes used for a high-performance product. Material selection was identified as important for changing conditions such as heat, and manufacturing processes were essential for dimensional accuracy and quality of the part.



COMPONENT SUMMARY





Camshaft Clamp



The main cam shaft clamp has a multipurpose function. It holds the camshaft firm and true to the central axis but also acts as a bearing substitute to allow for free rotation. The material must be hard so that the cam shaft can spin inside the clamp for many millions of rotations without the part wearing. The main body of this part is high pressure die casted. This is die-casting produces highly dimensionally accurate parts, which have small grains. The small grains of this process mean that the part will be very strong, not allowing dislocations to slip far in the material.



Cam Follower



A cam follower is a bearing that travels in linear movements and as it rotates, it causes a force on the follower, i.e. when the cam lobe reaches its peak it pushes the cam follower, meaning it rises and falls as force is applied. The cam follower, and other parts, must be adequately greased to minimise friction, however over greasing can lead to the cam follower skidding which causes wear. The cam follower is manufactured using forging which gives it a consistent grain structure and good strength which are essential properties for it to effectively carry out its function.



Cam Shaft



The function of the camshaft is to allow the valves to open at specific times to allow air fuel mixture in and combusted gas out. A double cam shaft means that one cam controls the inlet valve and the other controls the exhaust valve. Camshafts must be designed and positioned correctly to allow for the best performance. Incorrect positioning could lead to overheating due to friction which will also lead to engine wear. Most manufacturers use a CNC, using such a machine allows for accuracy, speed and very little human attention.



Exhaust Manifold



The exhaust manifold’s function is to conduct the exhaust gases from the combustion chambers to the exhaust pipe. Exhaust systems must be able to withstand the effects of many different factors; including high-temperature oxidation, condensate and salt corrosion, elevated temperature mechanical failure, stress corrosion cracking, and intergranular corrosion. Investment casting would be used for the manufacture of this component as it is used for products which require high dimensional accuracy.



Retention Bolts



Cylinder heads bolts are used in conjunction with the cylinder head gasket to create a tight seal and prevent gas from escaping the cylinders during operation. It is essential that the cylinder head bolts create a strong and even clamping force around the cylinder block. Cylinder head bolts are made using a strong alloy steel which can include nickel, molybdenum, titanium, copper and carbon. The bolts are cut, cold forged, chamfered, heat treated and threaded accurately.





Faheem Aziz (MEng, DIS)



Product Design Engineer