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According to Motor Trend it has a cast-iron block and aluminum head. They apparently could have saved some weight if they made the engine entirely from aluminum (as with BMW).

Apart from weight, does anyone know what are the advantages or disadvantages of a cast-iron block compared to an aluminum block? Is an aluminum engine more accommodating to mods than a cast-iron one?
 

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Hey...is that my pic?!

The 2JZ-G(T)E is an older engine design (vintage from around '93, the precursor 1JZ-GTE came around '90) with an iron block. I think the main reason for this is because the JZ engine was meant to be turbocharged. An iron block, I suppose, is better-suited to withstand the stresses of turbocharging compared to an aluminum block.
 

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I'm no engine expert, but materials made of aluminum must be thicker to get the same strength as iron, cause iron is stronger - but Al is considerably lighter, so even though you need more of it, the net weight loss is significant. M3 engines are iron block, not sure about regular 3 series.
Impreza WRX engine is aluminum block, and turbo-charged of course.


[This message has been edited by ckolsen (edited January 21, 2001).]
 

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a cast iron block is much stronger and better suited to the heat and extra stress produced from forced induction.

that is why all the honda racers sleeve their blocks with cast iron ductile sleeves, and use products like block guard to strengthen it, because aluminum will flex/expand too much, where as cast iron is much much more durable.

that is one of the reasons why supras can go 8's with a stock bottom end. the IS will always have an iron block, if they continue to use the 2jzge motor.

Originally posted by MrEee:

According to Motor Trend it has a cast-iron block and aluminum head. They apparently could have saved some weight if they made the engine entirely from aluminum (as with BMW).

Apart from weight, does anyone know what are the advantages or disadvantages of a cast-iron block compared to an aluminum block? Is an aluminum engine more accommodating to mods than a cast-iron one?
 

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By the way, the above pic was a working model of the 2JZ-GE, but I think it wasn't entirely made of iron (if there was any iron in it at all). If it were, I don't think the stands could support the weight of it.
 

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Just to add to what everyone has said so far. Aluminum has much lower fatique limit than Iron, so in the long run, Aluminum will fail earlier than Iron. It is true you can use more Al to gain the strength, but that also adds the physical size of the block. What they really should do is made the engine out of aerogel, now that is the material everyone will love. (for those that don't know, aerogel is a special material that has the same density as air and is superior in both thermal and strength properties than steel)
 

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Advantage for Aluminum block: Light weight, and the same thermal expansion as the aluminum heads so your head gasket has less expansion stress to deal with.

Advantage for Iron block: Typically stronger, and absorbs more of the engine noise.

Since lower weight=better performance and better fuel mileage, most new engine designs are of the "all aluminum" variety.

Yes, the GS300, IS300 and Supra have the same 2JZ iron block engine design. The LS430/GS430 have an aluminum block v8.

Yes, with forced induction the extra strength is welcomed. (Like in the turbo Supra)

Even though we are "stuck" with an old technology block in the IS300, we do have these nice things to fall back on:
1> The 2JZ-GE is a very smooth engine.
2> The 2JZ-GE is a very quiet engine.
3> The 2JZ-GE is a VERY reliable, proven engine.
4> The 2JZ-GE with VVT-i makes a very usable, broad torque curve.

(sorry about the fuel mileage and weight...)
 

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Metal fatique depends on the structure, not just the material. In working with aluminum, of course you have to use thicker diameters etc. to get the same strength. But an engine block doesn't see much fatique stress, just moving parts like pistons, cams etc. I don't think it's as simple as "iron is stronger than aluminum", that's only true if the dimensions are the same. Iron is better for cylinder sleeves cause you're limited in diameters you can use. Remember, these are aluminum alloys too, not pure aluminum - they are very strong. Lexus will go to an Aluminum block, I guarantee it.
Same density as air? Does it float?

Originally posted by Daniel:
Just to add to what everyone has said so far. Aluminum has much lower fatique limit than Iron, so in the long run, Aluminum will fail earlier than Iron. It is true you can use more Al to gain the strength, but that also adds the physical size of the block. What they really should do is made the engine out of aerogel, now that is the material everyone will love. (for those that don't know, aerogel is a special material that has the same density as air and is superior in both thermal and strength properties than steel)
 

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no way lexus is going to design an aluminum block for a motor that is already being produced with an iron, and in addition, has a turbocharged version that takes full advantage of the stronger more durable iron block. the only way it will go all aluminum, is if they don't offer the 2jzge motor in it.


Originally posted by ckolsen:
Metal fatique depends on the structure, not just the material. In working with aluminum, of course you have to use thicker diameters etc. to get the same strength. But an engine block doesn't see much fatique stress, just moving parts like pistons, cams etc. I don't think it's as simple as "iron is stronger than aluminum", that's only true if the dimensions are the same. Iron is better for cylinder sleeves cause you're limited in diameters you can use. Remember, these are aluminum alloys too, not pure aluminum - they are very strong. Lexus will go to an Aluminum block, I guarantee it.
Same density as air? Does it float?

 

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i have had my supra turbo motor entirely assembled and on a stand for a month, and that has an iron block and aluminum head. i think that motor just has a painted iron block, and the average stand can hold 750 pounds, while the better ones are rated for a 1000. i think if i remember, the motor weighs around 450 to 500 pounds, so a decent engine stand should have no problem supporting it.


Originally posted by JW:
By the way, the above pic was a working model of the 2JZ-GE, but I think it wasn't entirely made of iron (if there was any iron in it at all). If it were, I don't think the stands could support the weight of it.
 

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Metal fatique depends on the structure, not just the material. In working with aluminum, of course you have to use thicker diameters etc. to get the same strength. But an engine block doesn't see much fatique stress, just moving parts like pistons, cams etc. I don't think it's as simple as "iron is stronger than aluminum", that's only true if the dimensions are the same. Iron is better for cylinder sleeves cause you're limited in diameters you can use. Remember, these are aluminum alloys too, not pure aluminum - they are very strong. Lexus will go to an Aluminum block, I guarantee it.
Same density as air? Does it float?
True, you can make up the strength of the alunimum by chaning the structural construction. And you actually do see fatique due to thermal expansion and the vibration from the chassis (although the latter is probably a very small factor).

Yes, aerogel is same density as air, or close to it, depending on the chemical composition. I have seen it float before, and if not floating, they will drop to the ground similar to that of feather. It is a great material that is currently used in space mission, but eventually should work its way to us consumers. BTW, all you need to make aerogel is some kind of alcohol and some type of silicon (don't remember the alcohol and the silicon is similar to that of sand).
 
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