Iron vs Aluminum blocks
09-20-2004, 07:10 AM
#21
Originally posted by Chi-TownWarrior
GQ
Do you have a idea on the cost of having darton install sleevs?.
GQ
Do you have a idea on the cost of having darton install sleevs?.
Hey...what part of SC do you live in? I am in Charlotte, NC.
09-20-2004, 09:46 AM
#22
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Similar to the Darton MID sleeves, I believe AEBS has sleeving technology that braces the sleeves while allowing for water circulation, yielding all the benefits of a closed deck as well as the cooling benefits of an open deck. Then again, I'm under the impression that they have some steep pricing. I'm not sure.
Phunk, would you care to share what you know about the major block sleeving companies (Darton, AEBS, Golden Eagle, etc) ?
Phunk, would you care to share what you know about the major block sleeving companies (Darton, AEBS, Golden Eagle, etc) ?
09-20-2004, 09:54 AM
#23
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[QUOTE]Originally posted by gq_626
Shopdog, unless my high school physics is failing me, iron is a much better conducter of heat than aluminum. That is why...for instance, if you put a piece of aluminum foil in the oven and touch it, it is hot...but not super hot. Do the same thing with a case iron skillet and you will have a 3rd degree burn in about 2 seconds.
Your high school physics is failing you. The thermal conductivity of aluminum is more than 4 times greater than iron. 205 watts per meter per degree Kelvin for aluminum and only 50 W/mK for iron. The reasons that aluminum foil removed from the oven cools so rapidly to the touch is that it has a *much smaller* mass than the iron skillet. This means it can hold much less heat in the first place. Its temperature is a function of how rapidly it transfers the heat away from itself to the air. Since it has a much higher ratio of surface area to mass, it transfers what little heat it holds to the surrounding air much quicker when you remove it from the oven.
Regarding the closed deck. Darton sells a closed deck that has some cooling jackets in it...I forgot what it's called...mid design or semi closed..or whatever. Point is that coolant can still circulate around the sleeve, and that is the design I prefer.
Any interposition of an intermediate material between the hot sleeve and the cooling water reduces the cooling rate of the engine, and causes the sleeves to be hotter.
Second, there is signficant lateral force on the cylinder walls as RPM and pressure increase. The pistons are not moving perfectly up and down inside the cylinders, they are actuallly rocking slightly side by side, caused by the force of the rods moving around the crank. This can cause the cylinders to walk and wooble...and with enough force..break.
Again, the thing which restrains and locates the sleeve is the clamping force applied between the head and the sleeve locating recess at the bottom of the block. The iron sleeve has to be thick enough to resist bending forces on its own. Consider a VW bug engine or a radial aircraft engine. They don't even have any block material surrounding the cylinders, yet they hold together fine. Or consider a CAT D9 diesel, or any large John Deere diesel engine. They all use wet sleeves that are located and held in place solely by the clamping force between head and the lower block. The combustion pressures, and lateral forces, of those big engines are much larger than are reached in an engine like ours.
The only examples I know where the cylinders must have lateral support are in Top Fuel engines, where the water passages are filled with cement, or omitted completely when the race block is cast. The conditions are *so extreme* in such engines that the cylinder walls aren't sufficiently strong to contain the pressure. Even then, the reason for the extra bracing is not to prevent the cylinders from "walking". It is to prevent them from *bursting* because of the extreme forces. They don't need to worry about cooling since the engine never runs for more than a quarter mile. We don't have that luxury.
Shopdog, unless my high school physics is failing me, iron is a much better conducter of heat than aluminum. That is why...for instance, if you put a piece of aluminum foil in the oven and touch it, it is hot...but not super hot. Do the same thing with a case iron skillet and you will have a 3rd degree burn in about 2 seconds.
Your high school physics is failing you. The thermal conductivity of aluminum is more than 4 times greater than iron. 205 watts per meter per degree Kelvin for aluminum and only 50 W/mK for iron. The reasons that aluminum foil removed from the oven cools so rapidly to the touch is that it has a *much smaller* mass than the iron skillet. This means it can hold much less heat in the first place. Its temperature is a function of how rapidly it transfers the heat away from itself to the air. Since it has a much higher ratio of surface area to mass, it transfers what little heat it holds to the surrounding air much quicker when you remove it from the oven.
Regarding the closed deck. Darton sells a closed deck that has some cooling jackets in it...I forgot what it's called...mid design or semi closed..or whatever. Point is that coolant can still circulate around the sleeve, and that is the design I prefer.
Any interposition of an intermediate material between the hot sleeve and the cooling water reduces the cooling rate of the engine, and causes the sleeves to be hotter.
Second, there is signficant lateral force on the cylinder walls as RPM and pressure increase. The pistons are not moving perfectly up and down inside the cylinders, they are actuallly rocking slightly side by side, caused by the force of the rods moving around the crank. This can cause the cylinders to walk and wooble...and with enough force..break.
Again, the thing which restrains and locates the sleeve is the clamping force applied between the head and the sleeve locating recess at the bottom of the block. The iron sleeve has to be thick enough to resist bending forces on its own. Consider a VW bug engine or a radial aircraft engine. They don't even have any block material surrounding the cylinders, yet they hold together fine. Or consider a CAT D9 diesel, or any large John Deere diesel engine. They all use wet sleeves that are located and held in place solely by the clamping force between head and the lower block. The combustion pressures, and lateral forces, of those big engines are much larger than are reached in an engine like ours.
The only examples I know where the cylinders must have lateral support are in Top Fuel engines, where the water passages are filled with cement, or omitted completely when the race block is cast. The conditions are *so extreme* in such engines that the cylinder walls aren't sufficiently strong to contain the pressure. Even then, the reason for the extra bracing is not to prevent the cylinders from "walking". It is to prevent them from *bursting* because of the extreme forces. They don't need to worry about cooling since the engine never runs for more than a quarter mile. We don't have that luxury.
09-20-2004, 10:06 AM
#24
The mid sleeve design essentially has a ring at the top that seals the sleeve against the block. But below that ring, the coolant is free to circulate as it would, similar to an open deck design.
Your analogies to John Deere diesel engines may or may not be accurate...I am certainly not an expert in engine building (or HS physics,for that matter). But a 3.5L engine running 25psi of boost and 700whp/1000crankHP may generate much more pressure and lateral stress than a John Deere diesel motor. They are two entirely different beasts. One revs to 7000rpm, the other to 3000rpm??? Same thing for an aircraft engine...very low operating RPM.
Your analogies to John Deere diesel engines may or may not be accurate...I am certainly not an expert in engine building (or HS physics,for that matter). But a 3.5L engine running 25psi of boost and 700whp/1000crankHP may generate much more pressure and lateral stress than a John Deere diesel motor. They are two entirely different beasts. One revs to 7000rpm, the other to 3000rpm??? Same thing for an aircraft engine...very low operating RPM.
09-20-2004, 10:20 AM
#25
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Originally posted by Chi-TownWarrior
GQ, Shopdog
Say the temp of the oven is 230 both elements approach the temperature at some exponential rate, Al's line is slower than Fe so as the both level out trying to reach 230 both at t= infinity. But since Fe (iron) is faster it will always be hotter, more at first less at the end. Iron would be less likely to warp also because it has a much higher melting point so it would warp a lot less at those high temps.
GQ, Shopdog
Say the temp of the oven is 230 both elements approach the temperature at some exponential rate, Al's line is slower than Fe so as the both level out trying to reach 230 both at t= infinity. But since Fe (iron) is faster it will always be hotter, more at first less at the end. Iron would be less likely to warp also because it has a much higher melting point so it would warp a lot less at those high temps.
Thermal conductivity and electrical conductivity are directly proportional in metals. That's why car radiators and electronic heatsinks are made of copper or aluminum instead of iron.
On the subject of warping, aluminum doesn't become hot short until heated to about 800F. Because of its good thermal conductivity, if sufficient cooling water is flowing, it won't reach that temperature in an engine. Iron doesn't become hot short until 1800 degrees, which is one reason it works better as a sleeve in direct contact with combustion gases. (The other reason is that cast iron is a better bearing material than aluminum, so wear is also less.)
Last edited by shopdog; 09-20-2004 at 10:24 AM.
09-20-2004, 10:45 AM
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Don't shoot the messenger, however did any of you catch this last months issue of Import Tuner?
Basically, the NISMO 350Z car runs a VQ30DETT(same bore/stroke as my car
) vs. the VQ35 in some kind of turbo form for durability during endurance racing in the GT500 class of the JGTC Touring car championships. Just some food for thought, since they're running 460ish HP/520ish TQ.
Stats: http://www.jgtcusa.net/GT500/cars_500_1.html
More info on the JGTC series COMING TO THE US Dec. 18,19 in Fontana, CA, http://www.jgtcusa.net.
Basically, the NISMO 350Z car runs a VQ30DETT(same bore/stroke as my car
) vs. the VQ35 in some kind of turbo form for durability during endurance racing in the GT500 class of the JGTC Touring car championships. Just some food for thought, since they're running 460ish HP/520ish TQ.Stats: http://www.jgtcusa.net/GT500/cars_500_1.html
More info on the JGTC series COMING TO THE US Dec. 18,19 in Fontana, CA, http://www.jgtcusa.net.
09-20-2004, 11:36 AM
#27
Originally posted by shopdog
Your grasp of thermodynamics is as bad as GQs. Try this simple high school physics experiment. Take an aluminum wire or rod about 6 inches long, and an iron rod of the same length and diamenter. Hold each one by an end in a hand. Now put the far ends in a flame. Which one do you have to drop first? It will be the aluminum one, because it conducts heat so much better than iron.
Thermal conductivity and electrical conductivity are directly proportional in metals. That's why car radiators and electronic heatsinks are made of copper or aluminum instead of iron.
On the subject of warping, aluminum doesn't become hot short until heated to about 800F. Because of its good thermal conductivity, if sufficient cooling water is flowing, it won't reach that temperature in an engine. Iron doesn't become hot short until 1800 degrees, which is one reason it works better as a sleeve in direct contact with combustion gases. (The other reason is that cast iron is a better bearing material than aluminum, so wear is also less.)
Your grasp of thermodynamics is as bad as GQs. Try this simple high school physics experiment. Take an aluminum wire or rod about 6 inches long, and an iron rod of the same length and diamenter. Hold each one by an end in a hand. Now put the far ends in a flame. Which one do you have to drop first? It will be the aluminum one, because it conducts heat so much better than iron.
Thermal conductivity and electrical conductivity are directly proportional in metals. That's why car radiators and electronic heatsinks are made of copper or aluminum instead of iron.
On the subject of warping, aluminum doesn't become hot short until heated to about 800F. Because of its good thermal conductivity, if sufficient cooling water is flowing, it won't reach that temperature in an engine. Iron doesn't become hot short until 1800 degrees, which is one reason it works better as a sleeve in direct contact with combustion gases. (The other reason is that cast iron is a better bearing material than aluminum, so wear is also less.)
Shopdog......
Electric conductivity is proportional to the free motion of outter shell electrons, since Fe has more it allows for better conduction. You use copper like it is substitutable for Al, but in truth coppers elemental properties are more closely related to Fe. Look at a simple periodic table. Atomic weight and even the idea that d electrons are involved make those properties so. Do your simple experiment with electricity instead of heat and find out what one has the higher conductivity that way. Your heat way does not prove your point for many reasons. First is the fact that the better conductor will also conduct better to the air. The worse one will hold heat and give you a longer amount of dissapation time not meaning a lower temp. Those things depend not only on conduction but surface area. The surface area will determain the amount of heat dissapated to the air and you. Take the heat capacity of the metals, Al's is way too high meaning it will store up heat and heat up way too fast making it warp.
09-20-2004, 12:15 PM
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Looks like there are a couple different discussions going on in here... As for the idea of sleeving a VQ, it's not going to be necessary. I don't know how many of you guys have seen the VQ motors torn down, but there is a "partition" if you will, about halfway down the sleeve. Think of it like the Block Guard for a Honda motor, but pushed halfway down into the water jacket, instead of up at the deck. You don't need to worry about sleeve walk, and you really don't need to worry about bursting sleeves, since even the Honda engines don't burst their factory sleeves...
Most motors need to be resleeved for one of two reasons:
A Horrendous detonation cracks a sleeve, or
B The sleeve walks, usually due to extremely high side loads, caused by high RPM
Power does not kill them, detonation does.
Most motors need to be resleeved for one of two reasons:
A Horrendous detonation cracks a sleeve, or
B The sleeve walks, usually due to extremely high side loads, caused by high RPM
Power does not kill them, detonation does.
09-20-2004, 01:34 PM
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Well I'm new to the import world, but this is more an FI/Metalergy problem. From our side Aluminum blocks are still used, but a common practice to build big boost in aluminum blocks is to resleeve them. Darton makes a really strong mid sleeve that's used by domestics and imports alike. It's not nearly as cost effective as an Iron block, but you will save weight and have a stronger final product. For a price comparision, a Darton resleeved Aluminum LS1 would cost you around $4K w/o the cost of the motor. An iron block can be purchased new for ~$600. The Darton block will have superior weight, strength, and cooling, while the Iron block has far superior bang for the buck. But this is in our world, not sure how it works for the VQ35. I'm just learning.
Mike
Mike
09-20-2004, 08:03 PM
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I believe Iron blocks will retain more hp per cylinder than Al blocks, due to the fact that some of the energy is lost in the form of heat through the Al block.
09-20-2004, 08:17 PM
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Originally posted by G35sDriver
I believe Iron blocks will retain more hp per cylinder than Al blocks, due to the fact that some of the energy is lost in the form of heat through the Al block.
I believe Iron blocks will retain more hp per cylinder than Al blocks, due to the fact that some of the energy is lost in the form of heat through the Al block.
09-20-2004, 08:45 PM
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Originally posted by Enron Exec
That made absolutely no sense at all. Im sorry but im using that as a sig.
That made absolutely no sense at all. Im sorry but im using that as a sig.
Accepted cylinder-head theory contends that iron heads do not conduct as much heat away from the cylinder as aluminum does, so the iron heads should make more power—everything else being equal.
That was my point (though the website i posted shows exactly the opposite). Now you mind taking that quote out of your sig please? I was only trying to help.
Just in case your still having trouble following me (this is all in theory):
Aluminum heads dissipate (get rid of) heat much faster than iron heads. The rapid heat loss from the combustion chamber results in reduced combustion chamber pressures (heat equals pressure); similar to the effect that lowering the compression ratio lowers cylinder pressure.
Last edited by G35sDriver; 09-20-2004 at 08:49 PM.
09-20-2004, 09:00 PM
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Originally posted by G35sDriver
That was my point (though the website i posted shows exactly the opposite). Now you mind taking that quote out of your sig please? I was only trying to help.
That was my point (though the website i posted shows exactly the opposite). Now you mind taking that quote out of your sig please? I was only trying to help.
You said iron blocks, as in the bottom end, aka short block.
quote:
--------------------------------------------------------------------------------
Originally posted by G35sDriver
I believe Iron blocks will retain more hp per cylinder than Al blocks, due to the fact that some of the energy is lost in the form of heat through the Al block.
--------------------------------------------------------------------------------
[i]Originally posted by G35sDriver
http://www.chevyhiperformance.com/te...38/index3.html
Just in case your still having trouble following me (this is all in theory):
http://www.hughesengines.com/general..._head_tech.asp [/B]
http://www.chevyhiperformance.com/te...38/index3.html
Just in case your still having trouble following me (this is all in theory):
http://www.hughesengines.com/general..._head_tech.asp [/B]
09-20-2004, 09:02 PM
#35
Originally posted by G35sDriver
http://www.chevyhiperformance.com/te...38/index3.html
That was my point (though the website i posted shows exactly the opposite). Now you mind taking that quote out of your sig please? I was only trying to help.
Just in case your still having trouble following me (this is all in theory):
http://www.hughesengines.com/general..._head_tech.asp
http://www.chevyhiperformance.com/te...38/index3.html
That was my point (though the website i posted shows exactly the opposite). Now you mind taking that quote out of your sig please? I was only trying to help.
Just in case your still having trouble following me (this is all in theory):
http://www.hughesengines.com/general..._head_tech.asp
In the second link they didn't seem to run any test just give off a bunch of theorys, then admit that they like AL better. What is the point you are trying to get across?
09-20-2004, 09:05 PM
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Originally posted by Enron Exec
You said iron blocks, as in the bottom end, aka short block.
quote:
--------------------------------------------------------------------------------
Originally posted by G35sDriver
I believe Iron blocks will retain more hp per cylinder than Al blocks, due to the fact that some of the energy is lost in the form of heat through the Al block.
--------------------------------------------------------------------------------
You said iron blocks, as in the bottom end, aka short block.
quote:
--------------------------------------------------------------------------------
Originally posted by G35sDriver
I believe Iron blocks will retain more hp per cylinder than Al blocks, due to the fact that some of the energy is lost in the form of heat through the Al block.
--------------------------------------------------------------------------------
Ahhh in that case your going to have to exuse me. Im still learning about engines, and dont know all of the terminology (or how to use it properly for that matter/I never knew a short block was an iron block).
Those ar NA engines they are discussing. And aluminum heads make more power because they disapate heat better then iron heads. Lower temperture intake temps allow for denser air to enter the cylinders. Swain tech has a coating for the heads and valves to reflect heat away from the heads for just that reason.
09-20-2004, 09:05 PM
#37
Originally posted by Enron Exec
You said iron blocks, as in the bottom end, aka short block.
quote:
--------------------------------------------------------------------------------
Originally posted by G35sDriver
I believe Iron blocks will retain more hp per cylinder than Al blocks, due to the fact that some of the energy is lost in the form of heat through the Al block.
--------------------------------------------------------------------------------
Those ar NA engines they are discussing. And aluminum heads make more power because they disapate heat better then iron heads. Lower temperture intake temps allow for denser air to enter the cylinders. Swain tech has a coating for the heads and valves to reflect heat away from the heads for just that reason.
You said iron blocks, as in the bottom end, aka short block.
quote:
--------------------------------------------------------------------------------
Originally posted by G35sDriver
I believe Iron blocks will retain more hp per cylinder than Al blocks, due to the fact that some of the energy is lost in the form of heat through the Al block.
--------------------------------------------------------------------------------
Those ar NA engines they are discussing. And aluminum heads make more power because they disapate heat better then iron heads. Lower temperture intake temps allow for denser air to enter the cylinders. Swain tech has a coating for the heads and valves to reflect heat away from the heads for just that reason.
09-20-2004, 09:09 PM
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Originally posted by G35sDriver
Ahhh in that case your going to have to exuse me. Im still learning about engines, and dont know all of the terminology (or how to use it properly for that matter/I never knew a short block was an iron block).
Never thought of it that way (al heads reducing intake temp, and increase air density). Well you learn something new everyday.
Ahhh in that case your going to have to exuse me. Im still learning about engines, and dont know all of the terminology (or how to use it properly for that matter/I never knew a short block was an iron block).
Never thought of it that way (al heads reducing intake temp, and increase air density). Well you learn something new everyday.
09-20-2004, 09:09 PM
#39
Originally posted by G35sDriver
Ahhh in that case your going to have to exuse me. Im still learning about engines, and dont know all of the terminology (or how to use it properly for that matter/I never knew a short block was an iron block).
Never thought of it that way (al heads reducing intake temp, and increase air density). Well you learn something new everyday.
Ahhh in that case your going to have to exuse me. Im still learning about engines, and dont know all of the terminology (or how to use it properly for that matter/I never knew a short block was an iron block).
Never thought of it that way (al heads reducing intake temp, and increase air density). Well you learn something new everyday.
09-20-2004, 09:10 PM
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My point is long gone. I just wish he would take down that sig (really is that to much to ask?).
edit: Thanks Enron, that is VERY MUCH appreciated.
Now for some clarification on my part. Do remeber this is a)all theory no facts, b) im a super-newb.
Since Al dissipates more heat than Iron (not even sure how true this is), energy is lost at a higher rate, since heat is a form of energy (waste energy I believe its called). Kinetic energy is lost in the form of heat. Since Iron doesnt soak up as much heat, it wont soak up as much power. And thus, ceteris paribus (all things being equal), Iron cylinders should retain more of the kinetic energy.
Ehh Im not sure I explained it clearly. Maybe someone with a bit more automotive/physics knowledge can explain it better?
edit: Thanks Enron, that is VERY MUCH appreciated.
Now for some clarification on my part. Do remeber this is a)all theory no facts, b) im a super-newb.
Since Al dissipates more heat than Iron (not even sure how true this is), energy is lost at a higher rate, since heat is a form of energy (waste energy I believe its called). Kinetic energy is lost in the form of heat. Since Iron doesnt soak up as much heat, it wont soak up as much power. And thus, ceteris paribus (all things being equal), Iron cylinders should retain more of the kinetic energy.
Ehh Im not sure I explained it clearly. Maybe someone with a bit more automotive/physics knowledge can explain it better?
Last edited by G35sDriver; 09-20-2004 at 09:18 PM.