Closed Deck V. Open Deck
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Hijacker
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Closed Deck V. Open Deck
I hear these terms thrown around all the time, and I act like I know what they really are, but that's a lie. What's the difference?
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Hijacker
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well, what really got me thinking about the differences was this article by mike kojima i was reading. He was talking about block boring and honing. And when boring a block, it's best to do it with a deck plate on it, because it simulates having the head installed. But on an open deck block it's not necessary because of "the free standing cylinders".
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MaineExport
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BuudWeizErr
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Megaseth wrote:head design. the new QR uses a closed deck design, while the SR used an open deck. if im not mistaken, it deals with how they are cast. they're cast differently, and perform different because of it.
Umm, I was always under the impression that SR had closed deck design, and that honda b/d series engines had open deck designs:
SR:
B16:
ok, its simple.
when you pull the head on an open deck motor, the cylinder liners are free standing. another words, the cylinders are attached to the bottom of the block, and the coolant circulates around the cylinder liners. the top of the liners are not attached to the deck of the block. they seal against the head/headgasket directly.
a closed deck motor has the cylinder bores and block deck "closed" with just passages for the water and oil, not just free cylinder liners.
open deck blocks are almost always made out of aluminum or an alloy.
an american iron V8 will be closed deck.
when you pull the head on an open deck motor, the cylinder liners are free standing. another words, the cylinders are attached to the bottom of the block, and the coolant circulates around the cylinder liners. the top of the liners are not attached to the deck of the block. they seal against the head/headgasket directly.
a closed deck motor has the cylinder bores and block deck "closed" with just passages for the water and oil, not just free cylinder liners.
open deck blocks are almost always made out of aluminum or an alloy.
an american iron V8 will be closed deck.
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BuudWeizErr
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IvoryJ30t wrote:when you pull the head on an open deck motor, the cylinder liners are free standing. another words, the cylinders are attached to the bottom of the block, and the coolant circulates around the cylinder liners. the top of the liners are not attached to the deck of the block. they seal against the head/headgasket directly.
Is this why my friends Turbo B18C runs great with a radiator half the size of my stock radiator, and I still have cooling problems with my aluminum Koyo?
Seems taht would be the case if the coolant is able to completely surround the piston wall.. does it come down to open: cools better, closed: stronger ?
as far as the b18 having better cooling, i cant say if it because of the open deck design, or if it because the motor has a relatively small displacement.
my girlfriends old integra would hardly warm up in the winter. maybe its the extra surface area of the jackets in an open deck block, or the motor just doesnt retain heat.
my girlfriends old integra would hardly warm up in the winter. maybe its the extra surface area of the jackets in an open deck block, or the motor just doesnt retain heat.
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BuudWeizErr
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C-Kwik
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They each have advantages, but open deck designs are weaker at higher power levels. There are options on many open deck motors to basically close the deck. The advantages are that the cooling towards the top of the piston are better and according to some sources, helps reduce some emissions as well as the knock threshold. And the cylinder bore roundness is not effected by torquing the head down on an open deck block.
The reason for the different design is in the manufacturing process. Open deck designess are the result of die casting as opposed to the sand or foam casting in closed deck designed. In open deck blocks, they use dies and basically the die for the water jacket must be pulled out of the top of the motor. Die cast motors are more precisely cast and can be made smaller overall for the same internal dimensions. This results in a lighter and smaller package. Closed deck designs are a bit more crudely cast so it requires more tolerance is built into the casting so more metal is poured in and this results in an overall larger and heavier casting. Sand casting also creates an issue where sand can be lodged inside a cooling or oil passage and dislodged at a later time. It's a minor concern, but still a concern.
The reason for the different design is in the manufacturing process. Open deck designess are the result of die casting as opposed to the sand or foam casting in closed deck designed. In open deck blocks, they use dies and basically the die for the water jacket must be pulled out of the top of the motor. Die cast motors are more precisely cast and can be made smaller overall for the same internal dimensions. This results in a lighter and smaller package. Closed deck designs are a bit more crudely cast so it requires more tolerance is built into the casting so more metal is poured in and this results in an overall larger and heavier casting. Sand casting also creates an issue where sand can be lodged inside a cooling or oil passage and dislodged at a later time. It's a minor concern, but still a concern.