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#16
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well to put something in the jacket and not disrupt flow would be a physical impossibility. It's probable to do it with minimal disruptance. And yes Closing the deck is possible. Dunno how reliable it is though.
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#17
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So has anyone been having trouble with headgaskets, blocks or cylinder walls at elevated power levels?
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#18
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I think a better question would be, who is at elevated power levels
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#19
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Quote:
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Collin 1995 L AWD Locker 1987 Porsche 944 turbo 80k miles. MBC + Chips. Relatively Stock |
#20
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Quote:
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Collin 1995 L AWD Locker 1987 Porsche 944 turbo 80k miles. MBC + Chips. Relatively Stock |
#21
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Typically, I believe a deck is closed by welding the gap between the cylinder walls and the exterior of the block. Another method is to cut spacers from a piece of metal and press them into place.
I don't like either of these methods. The welding method seems like it would put enormous stresses on the block due to thermal expansion during the welding process. Perhaps there is a way to relieve these stresses, or perhaps it is welded with the whole block heated to a high temperature. ...or maybe it just isn't a problem. I would think it would be a fairly major concern. The spacer method seems inadequate. Cutting adequately sized spacers accurately enough to provide even support would be very, very challenging. It does however seem like it would result in lower stresses to the block and cylinder walls. To the best of my understanding, the primary (or only) reason to close the deck is because the cylinders tend to vibrate back and forth against the head gasket and this causes head gasket failures. This is the problem the professional Subaru rally teams encounter first. If reducing this vibration is the problem, the spacer method would be fairly straightforward and adequate. Disrupting the coolant flow isn't really an issue unless the coolant/oil ports in the head are blocked. Placing the spacers or welds slightly lower in the block or simply putting holes in them is sufficient. oab_au is right about cylinder sleeves. They can shift and don't have a large effect on strength. In the scenario where vibration is the primary problem, sleeves wouldn't do anything at all. A new sleeve would need to be quite thick to add any strength. You'd probably have to loose quite a bit of displacement to gain anything worthy of the trouble. The solution to preventing the sleeves from walking away from the head is to bore the cylinder a few millimeters shy of the bottom, leaving a lip for the sleeve to set on, (or over-boring the top and leaving a lip on the sleeve to hang from.) Personally, I believe all the fittings between the block and the head should be flare fittings with crushable washers, including the cylinders themselves. Expensive, but bullet-proof. I don't know as much about the methods, consequences, and advantages to closing the deck as I'd like to. From what I've gathered, even the experts really don't know much about it. Many believe it weakens the block or simply does nothing. Some people swear by it, and some just think it helps a little tiny bit or is only important in the most extreme circumstances. If anyone has more input on this, I'm curious. There's a lot a speculation around this subject. Regarding how increasing the bore might affect compression ratio; in the SVX it will, but only by a very small amount. This is directly related to the combustion chamber volume (volume inside when the piston is at TDC.) If this volume does not increase with the increase in bore, the compression ratio will increase. Because the combustion chamber volume is primarily in the cylinder head dome, increasing the cylinder bore will not have a large effect on the combustion chamber volume. If the piston had a concave top and was replaced with a larger piston with a larger concave top, this would tend to keep the compression ratio the same as before. The only way to reduce compression ratio is to increase the combustion chamber volume by increasing the size of the cylinder head dome or making the piston head concave (or just a little shorter.) |
#22
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Re: reducing the swept volume?
Quote:
phil
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~Phil Teal 1992 Subaru SVX Turbo - Sold in May 2011 to peace-frog. |
#23
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Re: Re: reducing the swept volume?
Quote:
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~Phil Teal 1992 Subaru SVX Turbo - Sold in May 2011 to peace-frog. |
#24
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Quote:
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Danny 1994 Silver SVX in hybernation, awaiting for the monsterous awakening (Lebanon) 1967 Mercedes-Benz 250SL Euro Specs, Hard/Softtop, White/Red. Under Complete Restoration 2013 Mercedes-Benz SL350 Euro Specs, White/Red. Mint... Another step into SL Collection. |
#25
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Quote:
__________________
Danny 1994 Silver SVX in hybernation, awaiting for the monsterous awakening (Lebanon) 1967 Mercedes-Benz 250SL Euro Specs, Hard/Softtop, White/Red. Under Complete Restoration 2013 Mercedes-Benz SL350 Euro Specs, White/Red. Mint... Another step into SL Collection. |
#26
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guys I was thinking of something, if stroking an engine will make the metal gap between piston chamber and water passages thinner. this in fact will heat up the engine more than usual and will cause its wear to happen quicker... unless proper cooling is adjusted to this mod.
Is there by any chance a way to upgrade the water pump to spin quicker same as upgrading the turbo bearings to spin more...???
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Danny 1994 Silver SVX in hybernation, awaiting for the monsterous awakening (Lebanon) 1967 Mercedes-Benz 250SL Euro Specs, Hard/Softtop, White/Red. Under Complete Restoration 2013 Mercedes-Benz SL350 Euro Specs, White/Red. Mint... Another step into SL Collection. |
#27
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Quote:
Doug
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1992 LS Touring (6/91) - Currently undergoing a five speed swap Black over Claret with spoiler; 235,000 miles; Mods: 2002 Legacy 5 speed, ACT Pressure Plate, Excedy Clutch, Short Throw Shifter, Aussie Powerchip 1992 LS Touring (6/91) Black over Claret with 2.5" setback spoiler; 202,000 miles; Mods: B&M Cooler 1994 LSi (4/93) Bordeaux Pearl; 198,000 miles; Mods: Weight reduction. 1969 Mustang GT Convertible 1970 Mustang Convertible 2000 Ford Excursion Sola lingua bona est lingua mortua. My Locker |
#28
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Quote:
__________________
Collin 1995 L AWD Locker 1987 Porsche 944 turbo 80k miles. MBC + Chips. Relatively Stock |
#29
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Just a morning coffee thought. Doug
__________________
1992 LS Touring (6/91) - Currently undergoing a five speed swap Black over Claret with spoiler; 235,000 miles; Mods: 2002 Legacy 5 speed, ACT Pressure Plate, Excedy Clutch, Short Throw Shifter, Aussie Powerchip 1992 LS Touring (6/91) Black over Claret with 2.5" setback spoiler; 202,000 miles; Mods: B&M Cooler 1994 LSi (4/93) Bordeaux Pearl; 198,000 miles; Mods: Weight reduction. 1969 Mustang GT Convertible 1970 Mustang Convertible 2000 Ford Excursion Sola lingua bona est lingua mortua. My Locker |
#30
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After looking at the pics of LAN's intake cutting and welding, it looks very difficult to make modifications to the stock intake because of the flowpath and shape of the runners. If you don't want to mess with internals, I think this woould be a great way to do it.
__________________
Collin 1995 L AWD Locker 1987 Porsche 944 turbo 80k miles. MBC + Chips. Relatively Stock |
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