Discussion
Apologies if this has been asked before, there's a Cerbera GT for sale that the ad says was the first 4.5 out of the factory. The ad also says the engine capacity is 4578cc. My question is, was this engine size factory standard on the first 4.5's? (or GT's as they were known) The ad mentions a number of other things that were standard on the 'GT's', which were later dropped due to cost, such as use of CF and aluminium??
Be interested to hear from anyone who owns one these early 'GT' spec cars
Thanks chaps,
Chilli
Be interested to hear from anyone who owns one these early 'GT' spec cars
Thanks chaps,
Chilli
Listen, I know nothing BUT my old man was a mechanical engineer and I thought that I remember him telling me that a forged crank would be superior to a billet item.
Have I remembered this incorrectly ?? ( I was 8 at the time )
Oh, and OP I've just seen this whilst trawling through previous articles. Dunno if it'll help
Have I remembered this incorrectly ?? ( I was 8 at the time )
Oh, and OP I've just seen this whilst trawling through previous articles. Dunno if it'll help
I spoke to nemasis about this a few months ago (and have been drinking Absinthe since then so the memory is faded/jaded) but there were 6 'GT's which were basically early 4.5s, with some slight suspension difference and they came fully loaded with extras. I gave him my car details and it was the 13th 4.5 off the line, and was specced exactly the same as the 'GTs' so whilst not labeled as such, there where about 16 GTs produced. Then it all reverted back to 4.5 etc
PS Mr C, the 2 cranks are 'cast' (as the name suggests)and forged/billet (cut from one solid piece/billet)...get me and my technical answers lol
PS Mr C, the 2 cranks are 'cast' (as the name suggests)and forged/billet (cut from one solid piece/billet)...get me and my technical answers lol
Edited by FUBAR on Tuesday 24th September 16:54
Mr Cerbera said:
Listen, I know nothing BUT my old man was a mechanical engineer and I thought that I remember him telling me that a forged crank would be superior to a billet item.
Have I remembered this incorrectly ?? ( I was 8 at the time )
Oh, and OP I've just seen this whilst trawling through previous articles. Dunno if it'll help
Billet steel is the stronger of the two typically. Does depend on the grade of steel used but having a crank machined from a solid billet of graded steel is stronger than forging one, I believe normally rated at around 20% but as mentioned that will depend on the steel used.Have I remembered this incorrectly ?? ( I was 8 at the time )
Oh, and OP I've just seen this whilst trawling through previous articles. Dunno if it'll help
A billet is a forging. You forge the billet, which is a lump, and machine it to the shape you want. The alternative to forging is casting.
When working with metal like this you can either cast it to the shape you want and finish it with machining, cast a big lump and machine it to the shape you want, cast a big lump, pound it into a different shaped lump called a billet whilst still molten, then machine it, or pound it to something close to the shape you want when molten and finish with machining.
Billets are forged. Machining from billets is extremely wasteful and therefore expensive. It can work out cheaper than building a steelworks and making your own forging dies to batter molten metal to the shape you want however, so it's used for low volume production frequently.
When working with metal like this you can either cast it to the shape you want and finish it with machining, cast a big lump and machine it to the shape you want, cast a big lump, pound it into a different shaped lump called a billet whilst still molten, then machine it, or pound it to something close to the shape you want when molten and finish with machining.
Billets are forged. Machining from billets is extremely wasteful and therefore expensive. It can work out cheaper than building a steelworks and making your own forging dies to batter molten metal to the shape you want however, so it's used for low volume production frequently.
FUBAR said:
…. Mr C, the 2 cranks are 'cast' (as the name suggests)and forged/billet (cut from one solid piece/billet)...get me and my technical answers lol
Many thanks for that, James. I thought billet was just hot drawn and then machined to the required form once cold.
Thanks for such a clear explanation.
( My Dad will be turning in his grave for misquoting him )
It can be - forged or extruded doesn't really make much odds. The act of working the metal when still red hot homologates the crystaline structures of the molecules better than casting.
It all just depends what shape of billet you're making. Strictly speaking forging does mean hitting it which is obviously different to extruding it, but both achieve better uniformity of the structure than just pouring it in to a mould and letting it cool down
It all just depends what shape of billet you're making. Strictly speaking forging does mean hitting it which is obviously different to extruding it, but both achieve better uniformity of the structure than just pouring it in to a mould and letting it cool down
It can be - forged or extruded doesn't really make much odds. The act of working the metal when still red hot homologates the crystaline structures of the molecules better than casting.
It all just depends what shape of billet you're making. Strictly speaking forging does mean hitting it which is obviously different to extruding it, but both achieve better uniformity of the structure than just pouring it in to a mould and letting it cool down
It all just depends what shape of billet you're making. Strictly speaking forging does mean hitting it which is obviously different to extruding it, but both achieve better uniformity of the structure than just pouring it in to a mould and letting it cool down
Gents,
This is a subject which I love. I have a theory....
Do you think that a ferromagnetic metal, if cooled from molten in a magnetic field, would be stronger (or more dense) than normal ??
I was thinking of the cylinder liners in the AJP8 and forming them in a magnetic field within a centrifuge which could (?) make them denser and therefore allow larger overbore sizes in safety.
Any thoughts ?
This is a subject which I love. I have a theory....
Do you think that a ferromagnetic metal, if cooled from molten in a magnetic field, would be stronger (or more dense) than normal ??
I was thinking of the cylinder liners in the AJP8 and forming them in a magnetic field within a centrifuge which could (?) make them denser and therefore allow larger overbore sizes in safety.
Any thoughts
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