What's a reverse dome piston (small block)?
- Thread starter dibbons
- Start date
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A reverse dome piston(aka dish piston) is concave into the surface of the piston. Literally the opposite of the dome. This can be for valve clearance or to keep compression manageable on a small chamber head.
Note that many piston mfg's "incorrectly" identify positive or negative cc's.
A dome should be negative cc's because it makes the compression chamber smaller.
A dish (aka reverse dome) adds cc's to tje combustion chamber
dibbons
Well-Known Member
Thanks, I wonder why the just don't call it dish, like they used to.
mguner
How many is too many?
Technically because many are not a uniform shape. Some wordsmith decided to be more precise in description that "reverse dome" would better describe a "D" or heart shape indention rather than "dish"....
Closed Chamber Dish with 2 valve ReliefsTechnically because many are not a uniform shape. Some wordsmith decided to be more precise in description that "reverse dome" would better describe a "D" or heart shape indention rather than "dish"....
lol
340demon72
Well-Known Member
Boy those pistons (Bore Size: 4.030") ought to rattle around nice in a standard bore 340 (4.040")...............
Piston slap?lol
mguner
How many is too many?
My Wisecos in a 318...
Generous valve reliefs.
Seems no one knows what a reverse dome piston is. I do, so here it is.
Unlike a traditional dished piston, a reverse dome is exactly what it implies. The DIRECT opposite of a domed piston if that particular piston had a dome.
Here is where the two differ. The reverse dome retains the quench area of the piston, while a traditional dished piston does not.
The reverse dome is good in applications that otherwise would have too much compression, but still can benefit from some quench, such as long stroke, long rod strokers with small chamber heads.
Also some forced induction applications can benefit from reverse dome pistons during their low or no boost times, helping to keep the burn more efficient. Generally speaking, quench is a moot point in forced induction, but it can be used to help keep combustion cool and keep the burn even, which also of course helps fight detonation.
Reverse dome and dish pistons are NOT the same thing.
Unlike a traditional dished piston, a reverse dome is exactly what it implies. The DIRECT opposite of a domed piston if that particular piston had a dome.
Here is where the two differ. The reverse dome retains the quench area of the piston, while a traditional dished piston does not.
The reverse dome is good in applications that otherwise would have too much compression, but still can benefit from some quench, such as long stroke, long rod strokers with small chamber heads.
Also some forced induction applications can benefit from reverse dome pistons during their low or no boost times, helping to keep the burn more efficient. Generally speaking, quench is a moot point in forced induction, but it can be used to help keep combustion cool and keep the burn even, which also of course helps fight detonation.
Reverse dome and dish pistons are NOT the same thing.
Show'em a picture.
If I must. These are both 302 Ford pistons. First is the stock dished piston. No quench here. Next is the reverse dome. Clearly two completely different piston designs.
mguner
How many is too many?
Looks like a "D" shape to me..... Hemi pistons are also domed but have no quench...
That's true of the Hemi until about the 12:1 area. Then, the top of the dome becomes the quench area because it is nearing the head.
Here's a reverse dome in my stroker. They are almost zero deck, valve reliefs for clearance and the dish for quench and to control compression.
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