Len, how about that Hemi chamber as seen on 356 engines? with the super "domed" pistons? Just curious.
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New combo for the 2316!! 3 bolt 914 heads with a squareport?
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HAM Inc
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Hemi chambers are a whole other deal. Hemi's and pent roofs work much better with domes and partial domes, as a rule, than wedge chambers. Most hemi's require some sort of dome to achieve a decent C.R. In the case of some early 911's power went up with the CIS piston that had a half dome, over piston designs that had more dome and higher C.R.
The problem with domes is that they tend to interfere with the flame front. On a typical wedge head, let's say the typeIV, the plug is aimed toward the intake valve. Well a dome will have to be larger on the intake side because there isn't room for it on the exhaust side due to the fact that the piston chases the exhaust up the bore. This means the dome is squeezing the charge away from the plug.
Since most wedge chambers have a variation of this design, domes, over the years, have given way to aftermarket heads with smaller chambers. Just look at the myriad offerings to the V8 people. I'm not aware of any modern after-market wedge head that is designed to work with a dome.
But hey, maybe Jakes testing will find that there's something to them. I know he has been pretty dissatisfied with the squishy Type I at this early stage of testing. But I believe he plans to try a different cam in the near future.
The problem with domes is that they tend to interfere with the flame front. On a typical wedge head, let's say the typeIV, the plug is aimed toward the intake valve. Well a dome will have to be larger on the intake side because there isn't room for it on the exhaust side due to the fact that the piston chases the exhaust up the bore. This means the dome is squeezing the charge away from the plug.
Since most wedge chambers have a variation of this design, domes, over the years, have given way to aftermarket heads with smaller chambers. Just look at the myriad offerings to the V8 people. I'm not aware of any modern after-market wedge head that is designed to work with a dome.
But hey, maybe Jakes testing will find that there's something to them. I know he has been pretty dissatisfied with the squishy Type I at this early stage of testing. But I believe he plans to try a different cam in the near future.
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HAM Inc
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Perhaps the squishies would work better with a modified chamber shape. But I think its a band-aid where one isn't needed for the 2.0914 chamber.
As for the side plug heads, there is obviously room for improvement, but I'm not sure a piston dome of some sort is going to adequately compensate for the fact that the plug is located in about the worst possible position.
As for the side plug heads, there is obviously room for improvement, but I'm not sure a piston dome of some sort is going to adequately compensate for the fact that the plug is located in about the worst possible position.