prechambers mods?
prechambers mods?
I have to add, could be wrong here, but if anyone has ever paid attention to the carbon buildup on the piston in relation to pc holes, it seems pretty clear that the different diameters are there to control the pressure expansion in relation to the pc's location in the combustion chamber. As it is off center in the cylinder, the holes get progressively larger relative to distance from the cylinder walls. Look at the score marks. Smallest at the points where the prechamber is closest to the wall. Makes sense, consider how you'd like a pressure wave to behave in an environment where it originates off center, yet uniform expansion is desirable. Want all that extra pressure bouncing of cylinder walls and hammering down on one side of the piston significantly more than the other? Maybe splitting hairs here, but assuming we've more or less accepted that more pc flow is desirable, stands to reason that ideally you'd like to introduce more holes on a spacing and sizing gradient consistent with the existing trends and conically port them on a very slight negative axis (10-15 degrees?). Nice even expansion that way with the added bonus of a little extra downward encouragement. I'd imagine a decent egt drop over just increasing bore because of the theoretical possibility of less work being wasted and mayyyybe even some more love on the low end. I've got my 617a torn up for a rebuild, heads currently on my coffee table(yeehaw) receiving a fairly aggressive port/polish job, and, along with other goodies , I'm gonna go ahead and screw up my pc's while I'm at it. Granted, I have no intention on a dyno run unless both free and unrealistically convenient, who cares lol, but some loud obnoxious videos are guaranteed. Also though, I'd be curious to the idea of adding significantly smaller holes between the others and maybe even a little bit closer to the tip creating something of a "crown" pattern, again sized in gradient but tiny, in an attempt to create a pressure wave that is more centrally energetic/downwardly cuncussive without getting too crazy over the latter one that distributes energy, ideally, pretty much uniformly. Hopefully I get an eyebrow or two lifted with this.
Just to clarify, I noted on every piston head that the carbon buildup was very heavily concentrated in areas where the prechamber was closest to the cylinder wall, and especially in the areas around the smallest prechamber holes exhaust and were subject to the most turbulence. Now, in a perfect world one would think that a properly distributed combustion event would be unlikely to leave consistently localized deposits.
Juuuuust sayin...
PanicButton
08-15-2015, 04:48 AM #126Copied from flame front thread seeing as this seems more current
I have to add, could be wrong here, but if anyone has ever paid attention to the carbon buildup on the piston in relation to pc holes, it seems pretty clear that the different diameters are there to control the pressure expansion in relation to the pc's location in the combustion chamber. As it is off center in the cylinder, the holes get progressively larger relative to distance from the cylinder walls. Look at the score marks. Smallest at the points where the prechamber is closest to the wall. Makes sense, consider how you'd like a pressure wave to behave in an environment where it originates off center, yet uniform expansion is desirable. Want all that extra pressure bouncing of cylinder walls and hammering down on one side of the piston significantly more than the other? Maybe splitting hairs here, but assuming we've more or less accepted that more pc flow is desirable, stands to reason that ideally you'd like to introduce more holes on a spacing and sizing gradient consistent with the existing trends and conically port them on a very slight negative axis (10-15 degrees?). Nice even expansion that way with the added bonus of a little extra downward encouragement. I'd imagine a decent egt drop over just increasing bore because of the theoretical possibility of less work being wasted and mayyyybe even some more love on the low end. I've got my 617a torn up for a rebuild, heads currently on my coffee table(yeehaw) receiving a fairly aggressive port/polish job, and, along with other goodies , I'm gonna go ahead and screw up my pc's while I'm at it. Granted, I have no intention on a dyno run unless both free and unrealistically convenient, who cares lol, but some loud obnoxious videos are guaranteed. Also though, I'd be curious to the idea of adding significantly smaller holes between the others and maybe even a little bit closer to the tip creating something of a "crown" pattern, again sized in gradient but tiny, in an attempt to create a pressure wave that is more centrally energetic/downwardly cuncussive without getting too crazy over the latter one that distributes energy, ideally, pretty much uniformly. Hopefully I get an eyebrow or two lifted with this.
Just to clarify, I noted on every piston head that the carbon buildup was very heavily concentrated in areas where the prechamber was closest to the cylinder wall, and especially in the areas around the smallest prechamber holes exhaust and were subject to the most turbulence. Now, in a perfect world one would think that a properly distributed combustion event would be unlikely to leave consistently localized deposits.
Juuuuust sayin...
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