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Discussion Starter · #1 ·
When I got my car and when my Mom got her 1.9t Volvo my Dad took a look at the engines and commented on how both cars have an aluminum block. He has a Bimmer so seeing cars being made nowadays using much ligther metals like aluminum was pretty strange to him. It was also strange to me because I to also thought that engines with cast iron blocks were sterdier in the long run.
Could somebody give me some useful information on this as I am still somewhat confused over the reasoning behind the choice of metal that is used to forge an engine block.
 

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Re: Is cast iron better than an aluminum block? (2.0LGtiPwr)

Aluminum had better heat properties than steel. Steel will hold heat all day long, whereas aluminum wil discipate it faster. Inside the cylinders there are steel sleeves that combustion takes place in. The internals are all steel and mounted in steel sleeves. No biggie
The funniest thing though...
One time my dad and I were at a machinest getting the head from my MGB planed and sitting on a bench was a 3 cylinder aluminum black for a Geo metro. I swear it weighed 10 pounds
 

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Re: Is cast iron better than an aluminum block? (2.0LGtiPwr)

My dad's old Alfa GTV/Sprint Veloce (late 70's model, like '78 or something) had an all-aluminum block, but the damn thing didn't have the sleeves in the cylinders...
That's the way they were designed. Thing also had mechanical fuel injection that required constant supervision. It makes me wonder why I crave the new 156 GTA so much, but I do...
 

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Re: Is cast iron better than an aluminum block? (chris86vw)

quote:[HR][/HR]Its a cast iron block with an alluminum head, not an aluminum block.
chris
[email protected][HR][/HR]​
Some newer engines, like the Volvo 1.9t, are all-aluminum including the block.


[Modified by BostonMk4, 1:40 PM 5-31-2002]
 

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Re: Is cast iron better than an aluminum block? (BostonMk4)

An aluminum block is much lighter, but much more expensive. I also remember reading an engineering article saying that the high sulfur content in U.S. fuel causes the aluminum to deteriorate, hence the iron/steel cylinder liners. My feeling is that the iron blocks are more durable. Any engineers out there?
 

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Re: Is cast iron better than an aluminum block? (2.0LGtiPwr)

There are a number of reasons to mfg's use aluminum blocks and/or heads. The first and foremost is to increase the power to weight ratio. Aluminum is lighter than cast iron therefore the HP/Weight ratio is increased...car goes faster with less power and consumes less fuel.
The drawback is that aluminum is no match for cast iron in terms of durability from heat cycling...cast iron warps.....pistons generally don't like that too much.
 

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Re: Is cast iron better than an aluminum block? (Frenchtimothy)

Honda's use aluminum heads and blocks. The block has iron sleeves for durability.
The head is very hard (dense) to drill into whereas the block is soft like butter.
Most of the problems associated with the Honda motors (when modding them) is that the block tends to crack under high boost conditions.
Most people "sleeve" the block with ductile iron for added strength when using a turbo or supercharger.
Iron is stronger. ie. the 1.8T motor. APR has their S4 using 30+psi in stock form.
Can't do that with a Honda.
 

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Re: Is cast iron better than an aluminum block? (TreyS)

quote:[HR][/HR]ie. the 1.8T motor. APR has their S4 using 30+psi in stock form.[HR][/HR]​
Ummmmmmm.... If you think the S4 has a 1.8t your nuts. It has a 3.something liter twin turbocharged V-6 under the hood.
 

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Re: Is cast iron better than an aluminum block? (1987&2001Jettas)

quote:[HR][/HR]ie. the 1.8T motor. APR has their S4 using 30+psi in stock form.
Ummmmmmm.... If you think the S4 has a 1.8t your nuts. It has a 3.something liter twin turbocharged V-6 under the hood.[HR][/HR]​
Ditto. The S4 has a 2.7L biturbo V6. Not sure about the 30psi, either. Can anyone support this number? Even 22psi with K04's (~1.5 bar) would be well over 450hp on the S4.
 

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Re: Is cast iron better than an aluminum block? (Max Rebo)

Hee hee. I was just thinking about my last Toyota truck that had a cast iron block and aluminum heads. (V6) The engineers didn't quite do their math right and because the heads dissipated heat so much faster than the block did, I had a leaking head gasket about every two weeks. I hate bi-metallic motors.
 
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