How to make a windowed piston

[Diamond Back]

I Have gotten a OZ DUAL CARBON Pedal Reed Block.. I need to window my piston,,,has any one done this before and have dimensions. I have a DREMEL and every bit posible,,,is two window slot or drilled holes better than large one window round or square shape ???

 

[butre]

in general the bigger the hole the better. I cut a square about one inch wide from roughly a quarter inch from the bottom ring groove all the way down to the bottom of the skirt. I make no effort to make it pretty, nobody's gonna see the piston anyway. just make it smooth with no sharp corners so chunks don't fall off and wreck your engine. mine is similar to the one in the photo, but without the section of skirt that extends below the skirt on the sides. be careful not to remove so much material that the piston rocks in the bore, that's a recipe for disaster.

 

[Diamond Back]

in general the bigger the hole the better. I cut a square about one inch wide from roughly a quarter inch from the bottom ring groove all the way down to the bottom of the skirt. I make no effort to make it pretty, nobody's gonna see the piston anyway. just make it smooth with no sharp corners so chunks don't fall off and wreck your engine. mine is similar to the one in the photo, but without the section of skirt that extends below the skirt on the sides. be careful not to remove so much material that the piston rocks in the bore, that's a recipe for disaster.

Did you notice an improvement in your motors performance, ? Exspecialy in the LOW END ?
I have heard both yes and no using a reed Block.. I was going to use the RSE 32mm Reed block,, But I THINK the OZ ZEDA DUAL CARBON FIBER PEDEL REED BLOCK 40mm is bigger and better,,, what you think.. The Engine Builder from ZEDA said dont worry about 3rd cylinder transfer port it dont do s**t with a good windowed piston,, and I will port the rest of the cylinder like always just widen things a little,,, I have extra base gaskets to mess around with port timing (height),,,Thank you Please write Back

 

[butre]

reed valves don't improve any one area, but rather broaden and smooth out the power band. that is to say you'll have less peak power but more usable power across the rev range. I have no personal experience with the zeda oz reed, but it's an improved clone of the RSE reed valve, which I can tell you is very good, if a little small. the biggest difference between the 32mm and 40mm reed block is the intake stud spacing. most engines these days are 40mm but 32mm intake spacing is still around. if you need a 32mm a 40mm won't work, and if you need a 40mm a 32mm won't work. measure your intake stud spacing center to center before buying either.

third transfer doesn't matter with a windowed piston, but a boost port is absolutely essential. that is linking the intake port with the combustion chamber by way of a milled out section. just match the height of the transfers. I find a rounded triangular shape to work best.

 

[Rusty_S85]

reed valves don't improve any one area, but rather broaden and smooth out the power band. that is to say you'll have less peak power but more usable power across the rev range. I have no personal experience with the zeda oz reed, but it's an improved clone of the RSE reed valve, which I can tell you is very good, if a little small. the biggest difference between the 32mm and 40mm reed block is the intake stud spacing. most engines these days are 40mm but 32mm intake spacing is still around. if you need a 32mm a 40mm won't work, and if you need a 40mm a 32mm won't work. measure your intake stud spacing center to center before buying either.

third transfer doesn't matter with a windowed piston, but a boost port is absolutely essential. that is linking the intake port with the combustion chamber by way of a milled out section. just match the height of the transfers. I find a rounded triangular shape to work best.

Don't want to hijack but this is somewhat on topic. You said that with a windowed piston transfer ports don't matter but a boost port is absolutely essential. How so?

I am curious because I have been doing some reading and from the reading I am seeing the boost port is said to be required if you don't run a windowed piston but if you run a windowed piston you do not need the boost port. That the boost port is only to allow more air volume in the engine that wouldn't be allowed in without. But with a windowed piston you get the extra air flow volume that makes the boost port not useful.

I am curious on this because I ordered the OZ reed valve and will be ordering at a later date a Zeda windowed piston for my build and want to understand fully what work I need to do to the cylinder jug in preparation for assembly.

 

[Deleted member 27811]

Don't want to hijack but this is somewhat on topic. You said that with a windowed piston transfer ports don't matter but a boost port is absolutely essential. How so?

I am curious because I have been doing some reading and from the reading I am seeing the boost port is said to be required if you don't run a windowed piston but if you run a windowed piston you do not need the boost port. That the boost port is only to allow more air volume in the engine that wouldn't be allowed in without. But with a windowed piston you get the extra air flow volume that makes the boost port not useful.

I am curious on this because I ordered the OZ reed valve and will be ordering at a later date a Zeda windowed piston for my build and want to understand fully what work I need to do to the cylinder jug in preparation for assembly.

W/ carbon fiber reeds both from BMW

 

[Guest-894844]

Did you notice an improvement in your motors performance, ? Exspecialy in the LOW END ?
I have heard both yes and no using a reed Block.. I was going to use the RSE 32mm Reed block,, But I THINK the OZ ZEDA DUAL CARBON FIBER PEDEL REED BLOCK 40mm is bigger and better,,, what you think.. The Engine Builder from ZEDA said dont worry about 3rd cylinder transfer port it dont do sh*t with a good windowed piston,, and I will port the rest of the cylinder like always just widen things a little,,, I have extra base gaskets to mess around with port timing (height),,,Thank you Please write Back

My performance got way worse once I installed the reeds. I still need a windowed piston tho. That's my next step

 

[Alex.G86]

My performance got way worse once I installed the reeds. I still need a windowed piston tho. That's my next step

because you can't run a windowed piston without reeds

 

[Jaycee604]

because you can't run a windowed piston without reeds

I still dont get why ppl think a windowed piston and reed valve can work solo lol

 

[Karl Snarl]

You don't need a windowed piston with a reed. You can always go case induction. No need to cut up the piston then. Just the case.