How To Measure for Compression Ratio Calculations / Vitara Evaluation
Thread Starter
Guest
Joined: Dec 2002
Posts: 1,463
Re: How To Measure for Compression Ratio Calculations / Vitara Evaluation
We used the numbers for a two layer Y8 gasket, which is .025''. After looking at the Y8 gasket, there is not one of the layers that looks like a good candidate for removal. The two outer layers have the embossing and sealing coating, while the single inner layer has specific coolant passages that look rather important for proper head cooling.
The stock Y8 gasket is .037'', the comparable Cometic is .030. This ends up being about .1CR difference. Not enough to really matter in this application. We could move to a .016" copper gasket, but really don't want to perform teh needed O-ring procedure need to properly use a copper plate gasket.
So it looks like the factory Y* gasket is what we are going to run with for now.
We used the A6 block because that is what we had. Our goal was to do a budget build using the cheapest components we could find, or have on hand.
Craig
The stock Y8 gasket is .037'', the comparable Cometic is .030. This ends up being about .1CR difference. Not enough to really matter in this application. We could move to a .016" copper gasket, but really don't want to perform teh needed O-ring procedure need to properly use a copper plate gasket.
So it looks like the factory Y* gasket is what we are going to run with for now.
We used the A6 block because that is what we had. Our goal was to do a budget build using the cheapest components we could find, or have on hand.
Craig
3.0 BAR
Joined: Feb 2003
Posts: 9,089
Re: How To Measure for Compression Ratio Calculations / Vitara Evaluation
i guess this doesnt take into account loses due to valve overlap and when valves open/close (so this is known as mechanical compression or static compression right?)
either way, good stuff.. and where's the next write up!
either way, good stuff.. and where's the next write up!
1.0 BAR
Joined: Jan 2006
Posts: 328
Re: How To Measure for Compression Ratio Calculations / Vitara Evaluation
Originally Posted by TunerToys
We used the TT H-Beams (of course) and had them honed to fit the floating pins on the Vitaras. Our machine shop charged us $40 for this.
For the piston to wall fitment, I was initially that the Vitaras were going to be a bit sloppy in the holes, but they appear to be okay. Since this is my first real hybrid of this type, I wanted a professional to verify my work. We used the same machine shop for milling the head mating surfaces of the block, and I had them hone the cylinders while they had the block. Ray (Basko Machine) stated that the bores were not round, and did a rigid hone, to correct it. He also had me bring down the Vitara pistions, to ensure the fitment, and said there would be no problem.
If the standard size Vitaras had not been usable, I had imagined that I could just get some oversize Vitaras. But once you start down the oversize/boring/machining path ($$$), you might as well buy some forged pistons. On that path, you'll already have a lot of money in machining the block, so why put in bargain basement pistons...
Craig
For the piston to wall fitment, I was initially that the Vitaras were going to be a bit sloppy in the holes, but they appear to be okay. Since this is my first real hybrid of this type, I wanted a professional to verify my work. We used the same machine shop for milling the head mating surfaces of the block, and I had them hone the cylinders while they had the block. Ray (Basko Machine) stated that the bores were not round, and did a rigid hone, to correct it. He also had me bring down the Vitara pistions, to ensure the fitment, and said there would be no problem.
If the standard size Vitaras had not been usable, I had imagined that I could just get some oversize Vitaras. But once you start down the oversize/boring/machining path ($$$), you might as well buy some forged pistons. On that path, you'll already have a lot of money in machining the block, so why put in bargain basement pistons...
Craig
Other than that, they're minty fresh. i only got charged 40$ for all of this work.. and also having them all hung w/ the spiro locks.
0.0 BAR
Joined: Mar 2007
Posts: 2
Re: How To Measure for Compression Ratio Calculations / Vitara Evaluation
Originally Posted by Walter
awesome write up!
i noob question abuot name of that "black box" that support dial indicator..how it's called in english it?
i noob question abuot name of that "black box" that support dial indicator..how it's called in english it?
