Open or closed??
15 September 2005, 02:40 PM
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Open or closed??
Guys..this may have been covered before but what exactly is the difference between open, closed and semi-closed deck?
Any1 know the adv/disadv of using a closed deck?
Any1 know the adv/disadv of using a closed deck?
15 September 2005, 02:53 PM
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Originally Posted by joedesi
Guys..this may have been covered before but what exactly is the difference between open, closed and semi-closed deck?
Any1 know the adv/disadv of using a closed deck?
Any1 know the adv/disadv of using a closed deck?
some smug smart **** will tell me so (As has happened once already today!!)
An open deck block has water jackets around the bore keeping it cool, these spaces obviosly make the block weaker than a closed becasue of the machining.
A closed deck block uses oil squiters to cool the bores and is stronger as
it is not machined around the bore (Soild).
A closed deck is stronger than an open deck.
Not sure about a semi closed though !
Rob
15 September 2005, 03:29 PM
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Originally Posted by joedesi
Cheers Rob...that kinda what i thought. if u look at some of the american websites they have huge debates on open vs closed
ps congrats on ur 600!! ive got 10
ps congrats on ur 600!!
ive got 10
And welcome, this is a great site, but you can end up
spending far too much money !!!!
Rob
15 September 2005, 05:01 PM
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mmm..
closed deck has a closed head face (apart from a few cooling holes) the water still flows around the cylinders, it has nothing to do with oil squirters. beacause of the material around the sealing face, its a lot more resistant to higher boost pressures/distortion/head gasket problems. found on some early sti's and RA's etc.
open deck does not have this, but the coolant flow through head and block is the same. found on all the other classics. pic here
http://img.photobucket.com/albums/v3...k/DSC00218.jpg
good explanation here.
http://www.cgperformance.com/subaru_block.htm
semi closed on new age is a halfway house with webs to try and stop the distortion, as in pic below.
http://img.photobucket.com/albums/v3...k/DSC00213.jpg
closed deck has a closed head face (apart from a few cooling holes) the water still flows around the cylinders, it has nothing to do with oil squirters. beacause of the material around the sealing face, its a lot more resistant to higher boost pressures/distortion/head gasket problems. found on some early sti's and RA's etc.
open deck does not have this, but the coolant flow through head and block is the same. found on all the other classics. pic here
http://img.photobucket.com/albums/v3...k/DSC00218.jpg
good explanation here.
http://www.cgperformance.com/subaru_block.htm
semi closed on new age is a halfway house with webs to try and stop the distortion, as in pic below.
http://img.photobucket.com/albums/v3...k/DSC00213.jpg
15 September 2005, 05:01 PM
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oh dear oh dear!
almost there.
Not all closed deck blocks have oil squirters. Oil squirters are small spray jets connecting with galleries in the block which spray oil at the underside of the piston to keep it cool. They only do this above certain oil pressures. They will have the ffect of lubricating and cooling the bore to some degree but this is not what they are for.
The open and closed decking refers to the amount of material between the main block casting and the bore casting which supports the cylinder liners. The cylinder liners themselves are steel sleeves within the aluminum cylinder wall that is part of the block.
Around the outside of the wall at the top of the cylinder (before it is closed by the cylinder head and gasket) there is no support to join it to the rest of the block face that the cylinder head bolts to.
This means the top of the cylinder bore and liner is more capable of walking (moving slightly) at high boost and high revs.
In a closed deck block, the block is cast with a supportive layer of block material connecting the walls of the block with the walls of the cylinder (which hold the liner).
This material does not go all the way down the height of the cylinder, it is several mm thick (not sure how many exactly) from the top down.
The extra material does have holes in it which communicate with the same water jacket below it as the open deck blocks have. Oilo squirters do not replace water jackets. some think that the holes in the closed decking is restrictive on the water system and thus the flow of water through the jacket must be reduced thus the cooling isnt as good with a closed deck.
The semi closed has less closing material than the fully closed, and the open deck has none.
The closed deck blocks are made with a low pressure casting technique which gives a different quality of aluminium havng more air bubbles in it. It is supposedly stronger, but is more brittle.
The semi and open deck blocks are made by mdeium pressure casting.
WRC cars use clsed deck blocks are their starting points before nikasil'ing the bores.
all the very power builds use closed deck blocks, but harvey showed that you could get enough power for most people using an open deck block.
almost there.
Not all closed deck blocks have oil squirters. Oil squirters are small spray jets connecting with galleries in the block which spray oil at the underside of the piston to keep it cool. They only do this above certain oil pressures. They will have the ffect of lubricating and cooling the bore to some degree but this is not what they are for.
The open and closed decking refers to the amount of material between the main block casting and the bore casting which supports the cylinder liners. The cylinder liners themselves are steel sleeves within the aluminum cylinder wall that is part of the block.
Around the outside of the wall at the top of the cylinder (before it is closed by the cylinder head and gasket) there is no support to join it to the rest of the block face that the cylinder head bolts to.
This means the top of the cylinder bore and liner is more capable of walking (moving slightly) at high boost and high revs.
In a closed deck block, the block is cast with a supportive layer of block material connecting the walls of the block with the walls of the cylinder (which hold the liner).
This material does not go all the way down the height of the cylinder, it is several mm thick (not sure how many exactly) from the top down.
The extra material does have holes in it which communicate with the same water jacket below it as the open deck blocks have. Oilo squirters do not replace water jackets. some think that the holes in the closed decking is restrictive on the water system and thus the flow of water through the jacket must be reduced thus the cooling isnt as good with a closed deck.
The semi closed has less closing material than the fully closed, and the open deck has none.
The closed deck blocks are made with a low pressure casting technique which gives a different quality of aluminium havng more air bubbles in it. It is supposedly stronger, but is more brittle.
The semi and open deck blocks are made by mdeium pressure casting.
WRC cars use clsed deck blocks are their starting points before nikasil'ing the bores.
all the very power builds use closed deck blocks, but harvey showed that you could get enough power for most people using an open deck block.
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15 September 2005, 05:09 PM
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Originally Posted by Adam M
oh dear oh dear!
almost there.
Not all closed deck blocks have oil squirters. Oil squirters are small spray jets connecting with galleries in the block which spray oil at the underside of the piston to keep it cool. They only do this above certain oil pressures. They will have the ffect of lubricating and cooling the bore to some degree but this is not what they are for.
The open and closed decking refers to the amount of material between the main block casting and the bore casting which supports the cylinder liners. The cylinder liners themselves are steel sleeves within the aluminum cylinder wall that is part of the block.
Around the outside of the wall at the top of the cylinder (before it is closed by the cylinder head and gasket) there is no support to join it to the rest of the block face that the cylinder head bolts to.
This means the top of the cylinder bore and liner is more capable of walking (moving slightly) at high boost and high revs.
In a closed deck block, the block is cast with a supportive layer of block material connecting the walls of the block with the walls of the cylinder (which hold the liner).
This material does not go all the way down the height of the cylinder, it is several mm thick (not sure how many exactly) from the top down.
The extra material does have holes in it which communicate with the same water jacket below it as the open deck blocks have. Oilo squirters do not replace water jackets. some think that the holes in the closed decking is restrictive on the water system and thus the flow of water through the jacket must be reduced thus the cooling isnt as good with a closed deck.
The semi closed has less closing material than the fully closed, and the open deck has none.
The closed deck blocks are made with a low pressure casting technique which gives a different quality of aluminium havng more air bubbles in it. It is supposedly stronger, but is more brittle.
The semi and open deck blocks are made by mdeium pressure casting.
WRC cars use clsed deck blocks are their starting points before nikasil'ing the bores.
all the very power builds use closed deck blocks, but harvey showed that you could get enough power for most people using an open deck block.
almost there.
Not all closed deck blocks have oil squirters. Oil squirters are small spray jets connecting with galleries in the block which spray oil at the underside of the piston to keep it cool. They only do this above certain oil pressures. They will have the ffect of lubricating and cooling the bore to some degree but this is not what they are for.
The open and closed decking refers to the amount of material between the main block casting and the bore casting which supports the cylinder liners. The cylinder liners themselves are steel sleeves within the aluminum cylinder wall that is part of the block.
Around the outside of the wall at the top of the cylinder (before it is closed by the cylinder head and gasket) there is no support to join it to the rest of the block face that the cylinder head bolts to.
This means the top of the cylinder bore and liner is more capable of walking (moving slightly) at high boost and high revs.
In a closed deck block, the block is cast with a supportive layer of block material connecting the walls of the block with the walls of the cylinder (which hold the liner).
This material does not go all the way down the height of the cylinder, it is several mm thick (not sure how many exactly) from the top down.
The extra material does have holes in it which communicate with the same water jacket below it as the open deck blocks have. Oilo squirters do not replace water jackets. some think that the holes in the closed decking is restrictive on the water system and thus the flow of water through the jacket must be reduced thus the cooling isnt as good with a closed deck.
The semi closed has less closing material than the fully closed, and the open deck has none.
The closed deck blocks are made with a low pressure casting technique which gives a different quality of aluminium havng more air bubbles in it. It is supposedly stronger, but is more brittle.
The semi and open deck blocks are made by mdeium pressure casting.
WRC cars use clsed deck blocks are their starting points before nikasil'ing the bores.
all the very power builds use closed deck blocks, but harvey showed that you could get enough power for most people using an open deck block.
It's to do with the amount of machining around the bore.
Rob
15 September 2005, 05:19 PM
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You were spot on with:
Though
Right, i'm still learning myself but i'll have a go, and if i'm wrong i'm sure
some smug smart **** will tell me so (As has happened once already today!!)
some smug smart **** will tell me so (As has happened once already today!!)
16 September 2005, 01:13 PM
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smart **** yes, smug no! 
oil squirters are removed from many cars if it is felt they place too much load on the oil pump.
manufactures use funky systems for this purpose as over cooling the pistons, especially in diesel engines leads to ineffecient combustion.
Open, closed and semi closed blocks are not machined. they are cast that way in the first place.
There are some companies who offer after market closed decking applied to normally open blocks. This is less popular now as semi closed 2.5s are available, and also because it didnt work very well as the welding process introduces thermal stresses which cause the liners to move when the engine is running hot.
If I can find it, I will dig out a picture to show you the result of mine running at 568bhp and 567lbft.
oil squirters are removed from many cars if it is felt they place too much load on the oil pump.
manufactures use funky systems for this purpose as over cooling the pistons, especially in diesel engines leads to ineffecient combustion.
Open, closed and semi closed blocks are not machined. they are cast that way in the first place.
There are some companies who offer after market closed decking applied to normally open blocks. This is less popular now as semi closed 2.5s are available, and also because it didnt work very well as the welding process introduces thermal stresses which cause the liners to move when the engine is running hot.
If I can find it, I will dig out a picture to show you the result of mine running at 568bhp and 567lbft.
19 June 2006, 11:12 AM
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Originally Posted by Adam M
smart **** yes, smug no!
oil squirters are removed from many cars if it is felt they place too much load on the oil pump.
manufactures use funky systems for this purpose as over cooling the pistons, especially in diesel engines leads to ineffecient combustion.
Open, closed and semi closed blocks are not machined. they are cast that way in the first place.
There are some companies who offer after market closed decking applied to normally open blocks. This is less popular now as semi closed 2.5s are available, and also because it didnt work very well as the welding process introduces thermal stresses which cause the liners to move when the engine is running hot.
If I can find it, I will dig out a picture to show you the result of mine running at 568bhp and 567lbft.
oil squirters are removed from many cars if it is felt they place too much load on the oil pump.
manufactures use funky systems for this purpose as over cooling the pistons, especially in diesel engines leads to ineffecient combustion.
Open, closed and semi closed blocks are not machined. they are cast that way in the first place.
There are some companies who offer after market closed decking applied to normally open blocks. This is less popular now as semi closed 2.5s are available, and also because it didnt work very well as the welding process introduces thermal stresses which cause the liners to move when the engine is running hot.
If I can find it, I will dig out a picture to show you the result of mine running at 568bhp and 567lbft.
So are the squirters good for the ej or not?
I have them with AVCS and they struggle to hold cam timing at low rpm (2500rpm ) and think this might be right when the squirers start squirting, and don't leave enough oil pressure to control the cams, and for that reason happy to leave them out, but not sure if there is a "proformance gain" ?
Thanks
Michael
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