What is a "safe" CR?
#31
02-11-2011, 12:10 AM
Ah, I am getting it! Cool.
That separation angle though, I don't see that anywhere on the sheet I posted about the cam, is that Lobe Centerline Angle on my sheet?
And what's that overlap on my sheet that's only 66.6 degrees?
I think I do understand the concept though. A wiiiider overlap actually means more pressure built up, because on the other side of the circle, that overlap, is both valves closed time, so a longer more pressurized stroke, equaling more torque. The smaller overlap, means that something is open for more time, and so either through correct direction flow, or reversion, pressure is lost for more of the stroke.
That separation angle though, I don't see that anywhere on the sheet I posted about the cam, is that Lobe Centerline Angle on my sheet?
And what's that overlap on my sheet that's only 66.6 degrees?
I think I do understand the concept though. A wiiiider overlap actually means more pressure built up, because on the other side of the circle, that overlap, is both valves closed time, so a longer more pressurized stroke, equaling more torque. The smaller overlap, means that something is open for more time, and so either through correct direction flow, or reversion, pressure is lost for more of the stroke.
Hmmm... I thought I was reading it stated 114 degree, but that is for exhaust, and it is stating the Lobe Seperation or "Centerline" is 110. That's fairly tight and should bleed some pressure at low rpm, moreso than the 114 I kept re-stating.
What manufacturer is this cam? Their cam specs don't read like the typical Crane or Comp.
Josh
#32
02-11-2011, 12:15 AM
Ya, I just read up on timing in the past hour or so, and I get the basics now (confirmed by your explanation of course).
I was thinking the springs attached the pick up base to the shaft, meaning that of course as the engine rotated faster, the shaft would put more and more tension on the springs, lengthening them, and letting the base sort of lag in relation to the pointer/contactor, retarding the timing.
I was thinking the springs attached the pick up base to the shaft, meaning that of course as the engine rotated faster, the shaft would put more and more tension on the springs, lengthening them, and letting the base sort of lag in relation to the pointer/contactor, retarding the timing.
#33
02-11-2011, 12:24 AM
All I know is what it says at the top of this sheet, which is that it is a "Preditor" cam. There is a company "Predator" cams I see just from a google, but I'm not sure if this one is just misspelled or what.
This info, as it sits here though, is from a DynoSim spreadsheet, but I didn't make it, the builder did.
This info, as it sits here though, is from a DynoSim spreadsheet, but I didn't make it, the builder did.
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