Mr. Zap, thanks for your continued interest. As I mentioned, my boat did show performance improvement. Keep in mind that the high pressure within the steam chest works in all directions. Since there is low pressure within the adapter cup, the high pressure steam within the steam chest is also pushing this cup and its attached old D valve toward the steam chest cover. Balance? Next season I'll try a gps run with and without the O-rings..Balanced vs unbalanced..Come along if you're in Maine!
That's correct. Before I made the conversion I would normally cruise at 70-80 PSI, a little above the boat's hull speed. Just at the point where the bow starts to rise. The friction between the D valve and the valve face at that pressure uses significant engine output. I can now get to the same cruising speed with about 60-70 psi. This is one reason why piston valves became popular very quickly. Relieving the forces pushing the D and the face does increase output.
I'm sorry that I'm so late in this reply. I haven't really been following comments, lately... Mea culpa! It's probably best to think of the aluminum "balance puck" just like a 2nd reversed "D" valve bolted back to back onto the the orginal "D" valve. The high pressure inside the steam chest pushes the "D" onto the port face. At the same time, the high pressure in the steam chest also forces the puck in the opposite direction toward the steam chest cover, providing significant pressure relief to the D valve.. The valve has been in operation for 3 seasons now without problems...
Could be. But the valve face and the contact area of the D are a water polished, almost "lapped" surface. That's one reason why I prefer a balanced D over a piston valve. An experienced steamgeeza once told me, "D valves wear in, piston valves wear out"
Only the results in the boat. The valve lap and lead were designed for steam so comparing them on compressed are on the bench really isn't fair. See my other comments. By the way, thanks for your interest.
I'm new to this, and I believe I have the grasp to what you "did", I'm struggling with why it helps based on your verbal descriptions in the video. You say it reduces the area (I'm going to assume you mean the total surface area on the high pressure side of the valve) that is exposed to the high pressure, thereby reducing the drag caused by the metal to metal friction between the D valve and the face where the 3 ports are.
I suggest not cover the viewing area when you point out the components. Use a long pointing stick? Yes, I know most of the parts and function so it didn't matter but for those who are new, it'll be different. Your info and what you're trying to explain were appreciated. Dorian
. But really in a 3D perspective, taking all the surfaces into account on the high pressure side of the valve, you are only reducing the top of the posts, as the rest of the area is not airtight. Could it be that the aluminum puck, with exhaust pressure in the inside, sealed by the o-ring being pressurized by the 4 small high pressure holes is physically hold the d valve in a more parallel alignment to the port face?
It is hard to believe you actually reducing the pressure between the two faces with the modifications. Do you have a before and after results? lowest PSI in both modes at what RPM?
Mr. Zap, thanks for your continued interest. As I mentioned, my boat did show performance improvement. Keep in mind that the high pressure within the steam chest works in all directions. Since there is low pressure within the adapter cup, the high pressure steam within the steam chest is also pushing this cup and its attached old D valve toward the steam chest cover. Balance? Next season I'll try a gps run with and without the O-rings..Balanced vs unbalanced..Come along if you're in Maine!
That's correct. Before I made the conversion I would normally cruise at 70-80 PSI, a little above the boat's hull speed. Just at the point where the bow starts to rise. The friction between the D valve and the valve face at that pressure uses significant engine output. I can now get to the same cruising speed with about 60-70 psi. This is one reason why piston valves became popular very quickly. Relieving the forces pushing the D and the face does increase output.
I'm sorry that I'm so late in this reply. I haven't really been following comments, lately... Mea culpa!
It's probably best to think of the aluminum "balance puck" just like a 2nd reversed "D" valve bolted back to back onto the the orginal "D" valve. The high pressure inside the steam chest pushes the "D" onto the port face. At the same time, the high pressure in the steam chest also forces the puck in the opposite direction toward the steam chest cover, providing significant pressure relief to the D valve.. The valve has been in operation for 3 seasons now without problems...
Could be. But the valve face and the contact area of the D are a water polished, almost "lapped" surface. That's one reason why I prefer a balanced D over a piston valve. An experienced steamgeeza once told me, "D valves wear in, piston valves wear out"
Only the results in the boat. The valve lap and lead were designed for steam so comparing them on compressed are on the bench really isn't fair. See my other comments. By the way, thanks for your interest.
I'm new to this, and I believe I have the grasp to what you "did", I'm struggling with why it helps based on your verbal descriptions in the video. You say it reduces the area (I'm going to assume you mean the total surface area on the high pressure side of the valve) that is exposed to the high pressure, thereby reducing the drag caused by the metal to metal friction between the D valve and the face where the 3 ports are.
I suggest not cover the viewing area when you point out the components.
Use a long pointing stick? Yes, I know most of the parts and function so
it didn't matter but for those who are new, it'll be different.
Your info and what you're trying to explain were appreciated.
Dorian
. But really in a 3D perspective, taking all the surfaces into account on the high pressure side of the valve, you are only reducing the top of the posts, as the rest of the area is not airtight. Could it be that the aluminum puck, with exhaust pressure in the inside, sealed by the o-ring being pressurized by the 4 small high pressure holes is physically hold the d valve in a more parallel alignment to the port face?
It is hard to believe you actually reducing the pressure between the two faces with the modifications. Do you have a before and after results? lowest PSI in both modes at what RPM?
use some steam oil, check out Keith Appletons vids
+Zach27 It already DOES use steam oil !! It's a compound marine engine!! Think before commenting!