Working with Metals: Aluminum

The advantages are many, and the disadvantages are few. Take for instance the issue of weight. Replacing the iron cylinder heads with aluminum units on a large Chevrolet will produce a weight savings of about 60 pounds. Replacing the engine block and heads can save you from 160 to 200 pounds. Losing weight when you are heavy is almost always good.


Heat dissipation is another advantage of aluminum. If you have ever cooked with an aluminum skillet versus a cast iron pan, you will see how much faster aluminum heats up and cools off. This fast movement of heat through the engine helps eliminate hot spots, and allows you to develop more power with less risk of damage.

Casting Call
Mention should be made of some of the basic ways of forming aluminum. First is cast. This means that molten aluminum is poured into a mold to form the basic shape of the part. Castings are fine for parts like engine blocks and cylinder heads that just sit and don't move around much.


In fact, cast materials can be preferable in these situations, as cast materials tend to be very stiff, but a bit brittle. Engine parts benefit from this stiffness, but obviously something that needs to flex a little should not be cast.

Forging Ahead
This is where forged aluminum comes in. A forged part is made from a red hot ingot of aluminum that is placed in a large hammer press, the press then smashes the hot aluminum into a mold. While this may sound a bit violent, what hasn't broken the aluminum has made it stronger. This method produces a much stronger and more flexible part.