Solid Aluminium Engine Blocks

[lightweight]

Many currently designed hyper-sportscars that are designing their engines in-house, choose to ignore conventional construction methods concerning the engine block.

Caparo and Melling (anyone know other manufacturers?) currently use a solid piece of aluminium and then grind it (is this the right word?) in order to shape it into the final engine block.

This construction method is used for racing cars, as it provides increased rigidity to weight ratios for the engine block, compared to conventional methods. On the downside, this construction technique cannot be used for mass production as it is really expensive: engine block output per hour is really low.

Anyone know any more info on this topic? Maybe some links? I googled it but I guess that I am using the wrong terminology as I can't get any results

[drakkie]

I assume they produce these parts by CNC-cutting them ? Perhaps googling with CNC provides some results.

For our tiger kitcar we designed a pedal-box. A company specialised in these machines will cut this for us for free (promotion).

[Matra et Alpine]

What evidence lightweigh of "hyper" car designs using CNC from billet?

It's an ideal prototypying tool but is VERY expensive for mass production and can't match casting for complex galleries and stress-reducing xurves. CNC'ing inside a box is very difficult and limited.

Many heads are CNC'ed because they don't need as complex galleries and less strength.
But low volume only.

AFAIK Caparo is currenlty one-off for the T1 ( anbd not sure of block construction ) but MCDs Nemesis was cast blocks.
Many of the new high-perfornacne compact engines have used bike technology to form the core. eg the Hayebusa cast blocks.

Would love to see what engines were going to stick with the extra weight of a machined rather than cast block. Got some links pls ?

[lightweight]

The info on the Hellcat was from
http://www.pistonheads.com/news/defa...?storyId=15791

The info about Caparo was from R&D magazine, Issue 14.

Thx about the CNC info though. Maybe I will find more info on the topic

[RacingManiac]

most blocks, even F1 ones, are usually casted then post machined. Casting method these days can get relatively complex feature with a reliable degree of accuracy, so there is really not much need to completely mill an engine block from a solid billet....

waste material is also a concern.....as a solid chunk of aluminum alloy billet would cost quite a bit....


As said, a prototype may be made from machine billet....but if they are making any quantity at all an inverstment casted block would make far more sense...

[culver]

I don’t know about this specific company but I have seen machined engine blocks. As others have noted there are issues such as machining inside the block and cost. Cost is a bit of a mixed bag. Assuming we can machine the blocks, it is cheaper to machine the block than create the casting then machine it IF we intended to make a very small number of blocks. The blanks for the casting are expensive and take time to produce. However, it doesn’t take long to hit that point where the extra investment up front becomes cost effective.
Now, speaking from the gas turbine engine field there are generally 4 ways you might make something (or a combination of those ways).

You can cast it. Casting gives you a near finished shape that generally only needs limited machine work. However, castings are relatively week. The metal from a casting is generally not as strong as other methods. To get a given amount of strength you need to make the casting ticker which adds weight. Also, casting produces metal that is less consistent than other methods. A 4mm wall in one part of the motor may be stronger than a similar 4mm wall some place else in that same block. This has to do with material properties in a casting. Early aluminum street car blocks were almost as heavy as iron blocks because the casting process was so variable. In order to guarantee strength the blocks were thicker than optimal. Casting tooling cost is expensive. In production parts casting is typically the cheapest if not always most material efficient way to make a part. Note that car uprights are cast.

You can forge it. Forging, like casting gives you a part that is near net shape but it can’t do the complex shapes that casting gives. Forged metal is stronger and more consistent in material property than casting. Thus forged parts can be thinner and yet stronger than cast parts. This works well for simple shaped parts like connecting rods. I know some jet engine “blocks” include forged parts. I can’t see anyone making a complete block from a forged part. Tooling is expensive and parts take longer to make than with casting.

You can machine it from billet. Like forging, billet stock will generally have very consistent and good material properties. The problem is you have to do LOTS of cutting and waist lots of material. However, sometimes this is the best way. I know some race cars use uprights machined from billet because the tooling cost are just about nothing which is important when making a run of 10-20 parts. It’s also very easy to make changes to the design because there is really no tooling, just change some code.

You can fabricate it. I don’t know of any fabricated modern piston engines but some of the very early motors were made from sheet and other parts that were assembled and welded together. Many race car parts including F1 uprights are actually welded assemblies of sheet metal. Many jet engines “blocks” are actually made from a combination of castings, forgings, machined parts and sheet metal all welded together. Sheet metal is typically going to give you VERY consistent material properties and great strength to weight ratios. It allows for delicate, thin walled parts that act like little unibody structures. Tooling costs are low, just some assembly jigs. Material costs are very low but assembly time is quite high and is generally all hand labor rather than machine time.

[Matra et Alpine]

CULVER Modern casting is much better than it was 10-15 years ago.
Using CAD a modern casting is easily made up for low volumes using epoxy/sand multiple comopnents assembled and then botom injected.

With castng it is MUCH easier to include internal fillets and webs to make the cast block much stronger that could be achieved with machining.

As you noted, the advantage of machining is very low volume flexibility.
I'll bet when the 100/week Mellings are being assembled in teh US ( that's the plan ) they won't be using a CNC block

[Mr.Tiv]

From billet, and it is pretty friggin' costly.

http://www.tvrcraft.com/

The NEW Melling V8 32 valve engine

Specifications:

Number of Cylinders: 8
Bore: 95mm
Stroke: 88mm
Max V.E: 101%
Inlet Valve Head Dia: 36mm
Exhaust Valve Head Dia: 30mm
Max. Valve Lift: 12mm
Max. engine rpm: 8000
Max piston speed: 76.66ft/sec.
Swept Volume: 4992.11cc
Max. bhp: 580 @7300rpm
Max. torque: 438ft/lbs @ 5400rpm
4 Valves/ Cylinder
2 Camshafts per bank
Timing Drive to Camshafts by gears then chain
Firing order is as 2 four cylinders
Crankshaft is flat plane
8 separate throttle bodies
Full engine management system
The primary construction will be from solid aluminium billet
Crankshaft is steel billet
Conrods are forged steel
Pistons are forged aluminium

TVRCraft have the exclusive rights to this engine, and as soon as they arrive one will be fitted into a Cerbera in front of a Tremec TKO transmission, then they will be installed into other selected models in the TVR range and also other vehicles.
The final stage will be to fit a supercharger and discover the upper limits of this engines capability.
This unit will be sold by us fitted, or as a crate motor.

Cost will be approx £14,000

Based on the provided specs, it sounds as though it works well enough.

[speednine]

$28,000 bucks (roughly)for a crate motor? I don't care if it was forged in the fires of hell, there are better options out there.

[Mr.Tiv]

Originally Posted by speednine

$28,000 bucks (roughly)for a crate motor? I don't care if it was forged in the fires of hell, there are better options out there.

it's more like 25 000. still, it's ridiculous.

[Matra et Alpine]

Originally Posted by Mr.Tiv

it's more like 25 000. still, it's ridiculous.

blame the weakness in the dollar

[Egg Nog]

Originally Posted by Mr.Tiv

it's more like 25 000. still, it's ridiculous.

Utterly ridiculous. Still cheaper than a similar BMW crate engine, but the LS7 is still the best option. You could have a normally-aspirated 700hp LS7 for far cheaper than this one if you wanted that much power. I'll bet any money that it would be lighter and more compact, too.

[Mr.Tiv]

Originally Posted by Matra et Alpine

blame the weakness in the dollar

I blame the strength in the sterling.

[Matra et Alpine]

Originally Posted by Mr.Tiv

I blame the strength in the sterling.

hmmmm ..... ........ compare across multiple currencies.

When one of them is going down against the "basket" of currencies then that is the "weak" one.

Wish it wasn't ... but there again ... time to come over an buy up some of your property for half price

[Mr.Tiv]

Originally Posted by Matra et Alpine

time to come over an buy up some of your property for half price

I wish I owned property... It sucks being young and nearly broke. On a postive note, my savings sounds much more impressive in pesos.

I am well aware of the dollar's weakness, I just prefer to deny it sarcasticly. In the future, I will remember smilies to show my lack of seriousness. I like to look at things from an optimistic angle. So I am going to say that the dollar isn't weak, other currencies are just comparatively strong-sounds better, doesn't it?