7cc valve relief looks like this?
01-01-2005, 07:03 PM
#1
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7cc valve relief looks like this? Changes on quench? Is this what it should look like? I would have just expected a big/deeper valve relief. This looks like a blower piston. Won't this effect how the fuel/air is burned in a NA motor over just a valve relief?
Last edited by BB; 01-02-2005 at 12:01 AM.
01-01-2005, 10:02 PM
#3
Yep, that's the same pistons I got. It's not a -7cc valve relief, it's a -2cc relief with a -5 dish. It caught me by surprise at first to. If you could actually see a-7cc relief, you'd be amazed. My buddies reliefs measured out at -4cc's and they are massivlly deep. About .370" to be exact. -7's would be crazy.
01-01-2005, 11:58 PM
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While this is the piston for a 382 stroker, 57cc heads, for a ~12:1 compression doesn't this dish change allot. For example, what about the quench area now? For this calculation you have to take the dish depth into account. So, the quench won't be right now.
Am I getting this right? The whole point of the 7 cc valve relief was for P/V clearance and CR. But, now I am concern of the physics of the combsution area that are no completely different.
Am I getting this right? The whole point of the 7 cc valve relief was for P/V clearance and CR. But, now I am concern of the physics of the combsution area that are no completely different.
01-02-2005, 12:16 AM
#5
It's not going to effect your quench area. If that was the case, you would never get the right quench, even without a gasket. The piston edges are still at the normal height, so that is where you measure from. The relief on that piston is .150" deep. My 244/.612" +2 Intake lobe cleared with .110" clearence, which means I only used .040" of the relief. I'm not sure how big a cam you are looking to run, but if you need a deeper relief, then you might want to send the pistons back and talk to Diamond about a -4cc relief. If you have a cam that will fill up that relief, it would be outrageous. My exaust lobe never hit the clay on the P/V check with a 248/.615" +2 lobe. Your combustion phiysics shouldn't be altered.
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01-02-2005, 11:42 AM
#8
4.060 diamond radial gas ported .043, 1/16, 3/16, they were pretty thick nitrous pistons so there was enough room to cut that big of relief.
I wouldnt worry about yours as long as you have enough piston the valve clearance. You can look as yours pistons more as 'reverse dome' pistons then dished, not going to really affect power output.
I wouldnt worry about yours as long as you have enough piston the valve clearance. You can look as yours pistons more as 'reverse dome' pistons then dished, not going to really affect power output.
