The way eco's are made is the same way saturn engine's are made they take a bunch of aluminum pellets and use a heat press to make the block
2.4 blocks are cast iron? sweet. Are the heads on them Iron too, or aluminum? Kinda wondering since I own one.
Weebel wrote:2.4 blocks are cast iron? sweet. Are the heads on them Iron too, or aluminum? Kinda wondering since I own one.
Aluminum.
Hell, I can't even think of the last iron headed engine GM produced. The RWD 2.8L from the late 80s-early 90s comes to mind, but I can't say it's that one for sure.
1989 Z24 Convertible - Dust Covered
2006 tC - Dust Covered, but driven more
Wrong wrong wrong.
The 2.4 is a cast iron block and aluminum head.
The 2.2/2200 is a cast iron block with an aluminum head.
The 2.2 Eco is an aluminum block and aluminum head.
The reason the Eco looks like styrofoam is the process used to cast it.
All engine castings are poured into a sand form (aka a 'core').
In conventional casting, the sand is pressed into a shape and put into a mold to form the internal passages and external surfaces. Lots of times the sand shifts (core shift) making a less than desirable casting. Other times it simply falls apart and the casting is scrap. The final surface finish looks like the sand that made it. This process is used for 2.2 and 2.4 heads and blocks.
The Eco uses a newer process know as the "lost foam process". Instead of simply pouring metal into formed sand, they instead start with a styroform like block casting and put the sand in around the foam. Because the foam is in there, the sand cannot move at all during casting. When they pour in the metal, the foam vapourizes as it fills with metal. The surface finish of this process ends up looking like the foam the sand was pressed against before it evaporated away.
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I used to do sand casting with styrofome in metals class in high school, it was fun but hard to do correctly until you got the hang of it.
I knew why the blocks look that way, I just didn't say anything because I thought the answer giving was close enough
protomec wrote:Wrong wrong wrong.
The 2.4 is a cast iron block and aluminum head.
The 2.2/2200 is a cast iron block with an aluminum head.
The 2.2 Eco is an aluminum block and aluminum head.
The reason the Eco looks like styrofoam is the process used to cast it.
All engine castings are poured into a sand form (aka a 'core').
In conventional casting, the sand is pressed into a shape and put into a mold to form the internal passages and external surfaces. Lots of times the sand shifts (core shift) making a less than desirable casting. Other times it simply falls apart and the casting is scrap. The final surface finish looks like the sand that made it. This process is used for 2.2 and 2.4 heads and blocks.
The Eco uses a newer process know as the "lost foam process". Instead of simply pouring metal into formed sand, they instead start with a styroform like block casting and put the sand in around the foam. Because the foam is in there, the sand cannot move at all during casting. When they pour in the metal, the foam vapourizes as it fills with metal. The surface finish of this process ends up looking like the foam the sand was pressed against before it evaporated away.
He is 99.99% correct. But it is called "Lost Foam Casting."
And this process is brought to you in part by Saturn's 1.9L engines. LN2s if I remember right, used something similar on their 2.2L OHV head too... . It has been 5 years since I've worked on a LN2.
ZlineDavid wrote:Weebel wrote:2.4 blocks are cast iron? sweet. Are the heads on them Iron too, or aluminum? Kinda wondering since I own one.
Aluminum.
Hell, I can't even think of the last iron headed engine GM produced. The RWD 2.8L from the late 80s-early 90s comes to mind, but I can't say it's that one for sure.
LoL @ GM. On Chevy Vega's "Durabuilt" had Iron head and aluminum block.
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The 3800 workhorse still uses iron heads and can be found in cars like the Monte Carlo, Grand Prix, Impala, etc. Not sure why an aluminum head was never developed for it in it's many years of use, but they are finally killing it off in the next few years.
ZlineDavid wrote:Weebel wrote:2.4 blocks are cast iron? sweet. Are the heads on them Iron too, or aluminum? Kinda wondering since I own one.
Aluminum.
Hell, I can't even think of the last iron headed engine GM produced. The RWD 2.8L from the late 80s-early 90s comes to mind, but I can't say it's that one for sure.
Tom Farris wrote:The 3800 workhorse still uses iron heads and can be found in cars like the Monte Carlo, Grand Prix, Impala, etc. Not sure why an aluminum head was never developed for it in it's many years of use, but they are finally killing it off in the next few years.
ZlineDavid wrote:Weebel wrote:2.4 blocks are cast iron? sweet. Are the heads on them Iron too, or aluminum? Kinda wondering since I own one.
Aluminum.
Hell, I can't even think of the last iron headed engine GM produced. The RWD 2.8L from the late 80s-early 90s comes to mind, but I can't say it's that one for sure.
Doh! Can't believe I missed that. *turns in "car guy" card*
1989 Z24 Convertible - Dust Covered
2006 tC - Dust Covered, but driven more
the early 6.0 trucks used a cast iron head also
id love a set of aluminum heads for a 3800
