F6 310 Vs 335 Gt Raceway

[cranny]

correct me if I am wrong but isnt cast iron stronger than alloy meaning that the i6 block is still a very strong block

[bunna]

Cast Iron is an alloy...

[bunna]

Furthermore (since I took too long to edit)

Depending very much on what you mean by "strength" and the composition of the aluminium alloy (since I'm assuming when you say "alloy" you in fact mean aluminium alloy), the aluminium is similar if not stronger (talking ultimate tensile strength).

Outright strength (tensile, compressive or yield) would not be the key consideration when choosing aluminium over cast iron. I would imagine fatigue behaviour, corrosion resistance, and thermal behaviour would all be fairly important, but most of all the ratio of stength/weight!

If aluminium alloys were superior to cast iron in the realms of strength/weight then:

a) auto manufacturers would not be persisting with using them and even lighter alloys (ie magnesium)

b) Planes would have cast iron wings and would no doubt fly slightly higher than buses.

Here endeth my rant.

[beastF6E]

Try putting much more than 400rwkw through any alaminium block and see how much strength it got.

Why do u think the LSX block is cast iron , the alloy blocks just cant handle big power.

[bunna]

*sigh*

As I tried to point out - "strength" is a very broad term, just as "alloy" is. Both are widely flung about from the same sort of people that make comments like "the laws of physics say this".

Why can't the aluminium blocks handle big power? As I pointed out, aluminium alloys have superior/similar "strength" properties compared to cast irons, so there must be another factor/multiple factors, not just outright "strength". I'm not here to say that aluminium is better than cast iron for engine blocks, all I'm pointing out is that there are more factors than just "strength".

One last point, based on your last comment I'm guessing its fair to assume formula 1 engines use a cast iron block? What about the veyron, konigsegg CCX, Murciélago, or the Enzo?

Edited 29/12/10 10:43 PM by bunna

[MYBAXRT]

Driving miss daisy.

[Guest XR09]

As Bunna pointed out. Cast is just that. A mix poured into a cast. Lots of room for errors. Forged is just that. Compressed or beaten into a shape. very little room for air and error/failure.

And then there is the grade of steel and aluminium.

Cast iron is brittle, well except some cast irons made to be "mallable". Stuff like cranks, cams and axles. Stuff that is cast but needs to be worked on to be finished.

Cast has a lower melting point to pure iron. And don't forget cast iron is made from pig iron (pure iron) and scrap metal. Cast iron is mainly used because it's cheap to make and mould.

As in grey cast. Grey being used for stuff that has to be ground or does not need so much strength; engine blocks, flywheels...some cranks, but usually they are made from even softer cast.

White cast is the strongest and used for bearings and rollers, stuff that can be cast and does not need work afterwards.

Plane engines use almost all aluminium. And not just because it is lighter. It can take the heat better. Cast alloy is soft or can be. Depends on the mix.

The rods in these are forged. The crank is of a grade that is up to the task and more.

Looking at those pic's is like Pamala with her pants down lol

The I6 is an amazing engine. I believe first designed in 1962. First put into production here in 1964. And still as torquey and almost efficient as anything else on the market. With stuff all modifications done to it in 47 years ??? An extra cam woo hoo. With a blower it's a gas.lol

Ford don't give us much.... but when they do ha ha yup it's good.

Edited 30/12/10 04:36 AM by XR09

[cranny]

its interesting how a lot of modern engines have gone to alloy blocks its not due to strength but more to do with weight and production cost. car manufacturers of today do not care if your engines implodes after your warranty runs out it just gives you another chance to buy another car. this is also called planned Obsolescence. car makers care for profit only and minimizing production costs not quality. if you take the falcon i6, it has been around since captain cook but for one reason it is a awesome engine. how many enzos lambos porsches do u see with upwards of a million kms on the clock original motor. most taxis around aus have upwards of 750ks on these engines. that's what I was referring to about strength. a mate of mine bought a Au falcon ex taxi with 946,000 kms on it still runs like a champ. I would like to see that from the coyote.

another interesting fact is commodores run a alloy V6 and if you ask any taxi driver they will say the same thing. the motor cant take the high Kms.

so what I am saying if we take apples with apples ie alloytec v6 vs ford i6 ford wins hands down in all departments.

yes all planes run allu but not for its strength buts its weight. planes get rebuilt and maintained on a regular basis so you really cant bring planes into this equation.(I WOULD LIKE TO SEE A ALL CAST IRON PLANE TAKE OFF)

[01txr]

Guess what Top Fuellers run alloy engine blocks, over 5000hp.

Cant be to weak then can it.

Differance again is cast verse forged.

Also search the most powerful Mitsubishi 4 cylinders and you will find that they are using billet

alloy blocks,cnc machined from forged billet blocks, same as top fuel engine blocks.

Also when these forged parts are done they make sure grain flow is in the best direction to make

it very strong as well by compressing the molten steel makes the molecules bond tighter.

A forged part of the same size as a cast part is heavier from being compressed.

Try breaking a board at right angle to grain, then try breaking running parrallel with grain.

Same principle here but stronger with metals.

Cast iron you will find the particle grain going what way it pleases and is a loose bond.

I will try to post up a high res close up of my broken rod, you may be able to see how bad the grain is.

A way of improving cast iron is to add more nickle to it, it makes it stiffer but at same I think it

makes it more brittle, and that's its limiting factor of adding high percentages of nickle.

Also the gm guys are getting good power from there alloy blocks.

Compare the design of our I6 engine and you will find the bottom end is very old tech when compared to

Euro and Asian cars.

The best thing with the bottom end that has been done is the block has lost useless weight with thickness reduced

and ribs added for the strength.

Compare pre ea engine blocks with the newer and you will see what I mean.

Also the sump now being extra main cap support helps for strength.

The crank is still old tech with better counter weight design and few other things.

The oil pump is good design except material used for the gears.

The top end is as good as others on the market.

the bottom end limits it power the topend is capable of.

The bottom end fails due to the old tech used.

If Ford would redo a alloy block I6 with block skirts encasing the mains, make caps a 4 bolt with outside studs angled/splayed

and bolt each side from the extended block skirts to main caps as per the sump to main bolts on current design.

add a forged crank with full counter balance go large on bore and bring stroke down to make it squared it would be

every bit as good as the new Coyote bar displacement.

Other than that it cant compare.

[bunna]

its interesting how a lot of modern engines have gone to alloy blocks its not due to strength but more to do with weight and production cost. car manufacturers of today do not care if your engines implodes after your warranty runs out it just gives you another chance to buy another car. this is also called planned Obsolescence. car makers care for profit only and minimizing production costs not quality. if you take the falcon i6, it has been around since captain cook but for one reason it is a awesome engine. how many enzos lambos porsches do u see with upwards of a million kms on the clock original motor. most taxis around aus have upwards of 750ks on these engines. that's what I was referring to about strength. a mate of mine bought a Au falcon ex taxi with 946,000 kms on it still runs like a champ. I would like to see that from the coyote.

another interesting fact is commodores run a alloy V6 and if you ask any taxi driver they will say the same thing. the motor cant take the high Kms.

so what I am saying if we take apples with apples ie alloytec v6 vs ford i6 ford wins hands down in all departments.

yes all planes run allu but not for its strength buts its weight. planes get rebuilt and maintained on a regular basis so you really cant bring planes into this equation.(I WOULD LIKE TO SEE A ALL CAST IRON PLANE TAKE OFF)

Whoa there nelly.

Firstly, Aluminium casting is more difficult than cast iron casting, and aluminium costs more, so consider your first point

As for minimizing production costs not quality, another load of utter crap. If you improve quality, costs reduce. Proven fact established well by a little country called Japan and followed by the rest of the world.

How many falcon taxis do 320km/h consistently? Obviously that very weak aluminium must be good for something.

Again, your argument that cast iron is stronger than aluminium because it "lasts longer" is rubbish. I've already pointed out that aluminium has superior strength properties than cast iron. The argument around durability and longevity is one of fatigue properties. Strength implies that the material cannot withstand a force without elastic or plastic deformation (very, very loose definition in order to keep this simple). If aluminium wasn't strong enough, the first time you put maximum load on the engine it would fail. If it copes with that force for 750k km and then suddenly fails that is fatigue.

On that point also, how many people on here plan on running a miami (or an I6T) for 750k km? Not many I'd fancy. As far as I know there aren't many XR6 turbo taxis getting around either...

Planes run aluminium for its strength/weight ratio, not just for weight (or we'd be seeing a lot more paper A380s). The point I was trying to make (and you either missed or ignored) was that it is clear from many examples that aluminium is not the crumble at the first sign of trouble material that you are making it out to be. In fact aluminium alloys are far superior to cast iron in most engineering applications, due to their superior strength/weight ratio and corrosion resistance. The only real benefit to cast iron is cost.

I'm not trying to single you out (so please don't take this personally), it just so happens that you've focused on two areas in which I am qualified to comment - I have a degree in Materials Engineering, and I work in Manufacturing Quality for Ford.