Alloys or metals in use for engine production

Hi all!
My name is Danny, I'm doing a lab project (:banghead:) and... this is my first thread... hurray! :cheers:
I need information about alloys that diesel engine parts are made of.
I mean from the block through the shafts and pistons and to the head...
Oh, yeah, and I need to compare that to standard petrol engines (I guess aluminum and cast iron or something right?)
So if someone here has information or links about this sort of stuff it will help me a lot... thanks.

For the most part there are three basic metals used in the construction of structural engine parts: Cast aluminum, Cast iron, and Forged steel. Occasionally you'll find cast steel in crankshafts but its rare.

Of the castings, there is also what is called "grey iron" often used in newer diesel blocks. Its main difference is the speed at which it is cooled. Its cooled slower so that the graphite (carbon) can crystallize into flakes in the casting. Although many grey iron alloys have less tensile strength than "regular" cast iron, they have the ability to absorb more vibrations. If you hit "regular" cast iron with a hammer, it rings. If you hit grey iron with a hammer it kinda makes a "thunk" sound.

In general, castings are rigid and more brittle. Forgings are less rigid, but will yield before breaking. The use of forged parts is usually equated with strength, and in many ways it is, but its main benefit is that it can absorb impacts and typically handle more abuse than castings.

In addition to the above post.... petrol engines generally are built to be lighter that diesel engines. Diesel engines generate far higher combustion chamber pressures (required for compression ignition) and thus need to be stronger and heavier.

Therefore, petrol engines can make much greater use of lightweight aluminum parts (blocks, heads and pistons) and greater use of less - dense cast parts (in place of forgings) for crankshafts, pistons and occasionally, connector rods.

This makes petrol engines lighter in general, and often cheaper to manufacture than an equivalent diesel engine.

Finally. magnesium is sometimes found in petrol engines, usually as a casting for engine covers, oil pans etc. However, I have never seen magnesium used for a diesel engine.

Thanks a lot!
So let's see if got it correctly...
In a diesel engine the block can be made out of forged steel or cast iron while petrol engines can use the lighter aluminum for the block?
Can a diesel head be aluminum? (i know most petrol engines use aluminum for the head).
The pistons-both diesel and petrol-aluminum is preferred right?

Thanks a lot!
So let's see if got it correctly...
In a diesel engine the block can be made out of forged steel or cast iron while petrol engines can use the lighter aluminum for the block?
Can a diesel head be aluminum? (i know most petrol engines use aluminum for the head).
The pistons-both diesel and petrol-aluminum is preferred right?

Car and truck diesel engine blocks are virtually always cast iron, not forged steel.
If a petrol engine block is not aluminum, then its made of cast iron too.
But their castings are always thinner and lighter than an equivalent diesel block.

In the past, diesel heads were always cast iron. However, the latest high-tech European diesels (used in cars) may use aluminum for the heads. Try checking the engine specs on the latest diesels from BMW, Mercedes and VW.

Aluminum is virtually always used for pistons. Cast and forged steel were used decades ago for low-revving engines but their weight was a disadvantage in higher-revving engines.

Now... HERE'S the EXCEPTION! Small industrial diesel engines built for smaller industrial and agricultural machines are often made with all-aluminum blocks and heads.

A few years ago, I owned some construction equipment powered by all-aluminum diesel engines ..... 3 cyl Isuzu liquid-cooled, single cylinder Bomag air-cooled and two-cylinder Lamborghini, also air cooled.

All these engines were less than 1 liter in displacement and did not produce very much power. Their low power output allowed them to be made from aluminum but did not make them suitable for car and truck use.

Thanks a lot!
So let's see if got it correctly...
In a diesel engine the block can be made out of forged steel or cast iron while petrol engines can use the lighter aluminum for the block?
Can a diesel head be aluminum? (i know most petrol engines use aluminum for the head).
The pistons-both diesel and petrol-aluminum is preferred right?

Blocks are almost always cast. I say almost because there are a rare few simple engine blocks that are billet or forged, but that is strictly for insane racing efforts. Blocks that you will see 99.999% of the time are either cast iron or cast aluminum. Heads are also cast iron or aluminum. Engineers can mix and match those materials for heads and blocks. Plenty of iron/iron combos out there as well as aluminum/aluminum. Also plenty of iron blocks with aluminum heads, but only a rare few with aluminum blocks and iron heads.

Internal rotating parts are where you start seeing forged things. Most cranks and rods are cast iron, but they can also be forged steel. Pistons are almost always aluminum and are either cast or forged.

The main difference between casting and forging is the temperature and the means of how its done. A casting is like making a candle. You melt the wax and pour it in a mold. When it cools you take it out. Forgings are made by heating the metal until its malleable but not liquid, then you squeeze it between two halves of the mold.

casting you put the two halves of the mold together, fill it with molten iron, then remove the molds. Forging you put soft steel in a one half of the mold, then force the other half of the mold on top.

http://www.youtube.com/watch?v=oRIbaGRB6tI a video showing casting iron complete with cheezy music.

http://video.google.com/videoplay?docid=2061543503984716778&ei=GCb1SbeKCpfUqAPtxIx0&q=steel+forging&hl=en a video showing forging of knives. The machinery you see is forcing the soft steel into a shape

only a rare few with aluminum blocks and iron heads.


Yup. the only one I know of was the Chevrolet Vega.

I believe Honda's 2.2 diesel was the first automotive diesel to use an aluminium block and head. It was launched in 2003.
If diesel use aluminium blocks then they use sleeves or inserts to get enough strength surrounding the cyilnder.
This diesel produces 400Nm of torque in it's highest state of tune and pushes some decent boost to get that.

I also beleive Isuzu helped honda design this engine.

http://www.cleanmpg.com/photos/data/501/Honda_2_2L_iCDTi_and_Emissions_Control.jpg