1flyingyogi
Well Known Member
Sorry if I'm using the wrong words, but if I heard correctly, Lycon said that my case was probably "decked" - meaning that someone in the past milled down the area of the case where the base of the cylinder sits with the purpose of increasing compression.
I had my cylinders ported and flow balanced and then installed high compression pistons (9.5:1 from Combustion Tech). When we put the cylinders back on (even before installing the pushrods), the prop would NOT turn all the way around. It gets stuck when any of the pistons moves to the top of the cylinder. (like the cylinder height is too short to allow the piston top to move any further)
I called Lycon and sent them some photos and took some approximate measurements and they think my case has been decked so these high compression pistons, although only .06" taller than the stock pistons, will top out because they're too tall for the cylinder. And the reason why is because the cylinder sits on a shorter base because it was milled down (decked).
So my question is, how do I verify? Is there some published dimension somewhere that I can look at and compare with mine? Would it be the distance from one side to the other where the cylinder base sits? (sorry I don't know what that's called).
Look at the photo attached and you can see a "lip" at the base of cylinder #3. It is raised a little bit. According to Lycon, that's where the face height originally was and it was milled down from there to effectively increase compression. Does that sound right to you guys?
At first we thought maybe we were sent the wrong pistons or that something was wrong with the cylinders or maybe they might have switched up my cylinders and sent the wrong ones. But I verified with Combustion Tech that it's the right pistons and Lycon said they definitely did not send me the wrong cylinders. So this is the only explanation. Or is it??
https://drive.google.com/open?id=106jJoV5f-DijA1PboIimnD-FYW98tNyO
I had my cylinders ported and flow balanced and then installed high compression pistons (9.5:1 from Combustion Tech). When we put the cylinders back on (even before installing the pushrods), the prop would NOT turn all the way around. It gets stuck when any of the pistons moves to the top of the cylinder. (like the cylinder height is too short to allow the piston top to move any further)
I called Lycon and sent them some photos and took some approximate measurements and they think my case has been decked so these high compression pistons, although only .06" taller than the stock pistons, will top out because they're too tall for the cylinder. And the reason why is because the cylinder sits on a shorter base because it was milled down (decked).
So my question is, how do I verify? Is there some published dimension somewhere that I can look at and compare with mine? Would it be the distance from one side to the other where the cylinder base sits? (sorry I don't know what that's called).
Look at the photo attached and you can see a "lip" at the base of cylinder #3. It is raised a little bit. According to Lycon, that's where the face height originally was and it was milled down from there to effectively increase compression. Does that sound right to you guys?
At first we thought maybe we were sent the wrong pistons or that something was wrong with the cylinders or maybe they might have switched up my cylinders and sent the wrong ones. But I verified with Combustion Tech that it's the right pistons and Lycon said they definitely did not send me the wrong cylinders. So this is the only explanation. Or is it??
https://drive.google.com/open?id=106jJoV5f-DijA1PboIimnD-FYW98tNyO