Piston Bowls

[Redbowties88]

The narrow width of the oval is as wide as a stock bowl. So the injectors do not spray over the edge any more than stock there. The long way in the oval is ~3/4" longer than stock.

In short, the shape was selected because it provides the best strength. Circular chambers do not.

Hmm, so if you took the most narrow section of the bowl of the pistons you are currently producing and used that as the diameter for a circular bowl it would in fact be weaker then the ones you're currently making? Or just not any stronger?

Again please forgive my ignornace

 

[Fingers]

The bowl is shallower across the narrow section. That puts more material over the pin. That is where the strength comes from.

 

[Redbowties88]

I do understand that, I guess what I'm asking is that is the extra volume of the bowl outside of what the spray pattern needs necessary for efficent combustion or is it more to keep the compression ratios at a near stock level? And would there be any benefits to having that portion of the bowl not cut, or would you just end up with a heavier piston that isn't any stronger?

Again forgive my ignorance becuase I'm just taking shots in the dark at something I'm not familiar with but I do appreciate your efforts in helping me understand.

 

[Fingers]

I do understand that, I guess what I'm asking is that is the extra volume of the bowl outside of what the spray pattern needs necessary for efficent combustion or is it more to keep the compression ratios at a near stock level? And would there be any benefits to having that portion of the bowl not cut, or would you just end up with a heavier piston that isn't any stronger?

Again forgive my ignorance becuase I'm just taking shots in the dark at something I'm not familiar with but I do appreciate your efforts in helping me understand.

I guess I really don't understand what you are asking. You seem to think the chamber is interfering with the spray pattern?

For a given CR you have to remove a given amount of metal. Period. Where to remove it is the trick. I have chosen to remove less over the pin and more away from the pin.

 

[Redbowties88]

I guess I really don't understand what you are asking. You seem to think the chamber is interfering with the spray pattern?

For a given CR you have to remove a given amount of metal. Period. Where to remove it is the trick. I have chosen to remove less over the pin and more away from the pin.

I realize its a hard thing to put into words. What I was saying was that the oval shape of the bowl was to provide enough material where it was needed to provide stregnth and the oval shape was to provide enough airspace to keep the compression ratio manageable.

Now lets pretend that compression ratio wasn't an important part of the equation, would there be an benefit in reguards to piston stregnth to making the piston with a round bowl but small (as wide as the most narrow section of the oval) and shallow enough to maintain the same level of structural metal in key areas? I'm aware that doing so would result in a very high compression ratio.

 

[x MadMAX DIESEL]

Sure it would probably be the strongest, but CR is an important part of the equation you need to keep it in check. Only other way would be to end up with something like a stock piston. Which is a weaker design, because of the pin location and meat around it. Pretty sure this was the only way to put meat where it needed, taking away where he could keeping it all the same weight... If it was about pure piston strength a flattop would be the best idea till you have to accompany injection spray and combustion. Not to answer for Fingers, but I think I know what you were asking and thats my take on it.

 

[Redbowties88]

Sure it would probably be the strongest, but CR is an important part of the equation you need to keep it in check. Only other way would be to end up with something like a stock piston. Which is a weaker design, because of the pin location and meat around it. Pretty sure this was the only way to put meat where it needed, taking away where he could keeping it all the same weight... If it was about pure piston strength a flattop would be the best idea till you have to accompany injection spray and combustion. Not to answer for Fingers, but I think I know what you were asking and thats my take on it.

I'm not concerned with compression ratio. I'm just curious if it would A: be stronger (which one would think but i'm not an engineer). and B: would still have enough of a bowl to facilitate an efficent burn without any harm from the pattern overspraying the bowl...

 

[baggedLB7]

The narrow width of the oval is as wide as a stock bowl.

Hmm, so if you took the most narrow section of the bowl of the pistons you are currently producing and used that as the diameter for a circular bowl it would in fact be weaker then the ones you're currently making?

If im reading right and you were to take the narrow section of the oval piston and use it as the diameter for a circular bowl wouldnt it be the same size as the factory bowl??????
Or am I not reading right?

 

[x MadMAX DIESEL]

Thats what I thought too. Only changed the cut depth in specific areas to keep compression the same, or close.

 

[Fingers]

I realize its a hard thing to put into words. What I was saying was that the oval shape of the bowl was to provide enough material where it was needed to provide stregnth and the oval shape was to provide enough airspace to keep the compression ratio manageable.

Now lets pretend that compression ratio wasn't an important part of the equation, would there be an benefit in reguards to piston stregnth to making the piston with a round bowl but small (as wide as the most narrow section of the oval) and shallow enough to maintain the same level of structural metal in key areas? I'm aware that doing so would result in a very high compression ratio.

Your basically talking about a stock bowl that isn't as deep. The ovals ARE as wide as stock at the narrow.

However, for grins, I did check the CR for a bowl only as deep as the oval over the pins. Comes out to 21.25:1. The additional chamber pressure would eat up the strength increase.

 

[THEFERMANATOR]

Have you considered making a round chamber, but larger in circumference than stock, but stay wit hthe shallower bowl? In essence it would be simliar to a delipped piston, but with a redesigned bowl to help contain the combustion event inside of the bowl better. Or would the larger circumference in the bowl weaken the pistons in the wrist pin area?

 

[Fingers]

I guess people just don't like oval bowls!

Folks, I've been working on this design for over two years now. Heck, this thread is almost two years old. I've looked at designs from the gas, big diesel and even the nitro burner worlds and borrowed what I could from each. I've asked a lot of questions and taken a lot of suggestions. I've cranked it through computer simulations and a couple less than scientific static tests. It is the best I (we) can do with the mechanical envelope that is available to us.

Will someone please break a set of these and shut me up?

 

[MarkBroviak]

I guess people just don't like oval bowls!

Folks, I've been working on this design for over two years now. Heck, this thread is almost two years old. I've looked at designs from the gas, big diesel and even the nitro burner worlds and borrowed what I could from each. I've asked a lot of questions and taken a lot of suggestions. I've cranked it through computer simulations and a couple less than scientific static tests. It is the best I (we) can do with the mechanical envelope that is available to us.

Will someone please break a set of these and shut me up?

I'm trying but we are having issues with other companies parts holding the power we are producing with them. I love the design and the way they run. Hopefully will have mine running at the end of this week! I will be using these pistons in my railcar when I build it also.:hug:

 

[adeso]

I guess people just don't like oval bowls!

Folks, I've been working on this design for over two years now. Heck, this thread is almost two years old. I've looked at designs from the gas, big diesel and even the nitro burner worlds and borrowed what I could from each. I've asked a lot of questions and taken a lot of suggestions. I've cranked it through computer simulations and a couple less than scientific static tests. It is the best I (we) can do with the mechanical envelope that is available to us.

Will someone please break a set of these and shut me up?

I'm going to try! Making plans to pull the engine and put these in, do a 1100 HP street truck that tows and pushes 8000lbs down the track way too fast. Would these weigh more or less than stock cut LB7s?

 

[THEFERMANATOR]

I guess people just don't like oval bowls!

Folks, I've been working on this design for over two years now. Heck, this thread is almost two years old. I've looked at designs from the gas, big diesel and even the nitro burner worlds and borrowed what I could from each. I've asked a lot of questions and taken a lot of suggestions. I've cranked it through computer simulations and a couple less than scientific static tests. It is the best I (we) can do with the mechanical envelope that is available to us.

Will someone please break a set of these and shut me up?

I'm just trying to understand the concept behind the oval bowl VS a round bowl. I don't have the modeling programs to get a 3D image of what is going on, but to me it would seem like a round bowl with a larger diameter would be better for overall performance than the oval bowl. On the other hand though I can see how the oval bowl would help to distribute the combustion force over the strongest area of the piston.

 

[S Phinney]

Does this bowl design facilitate a better flow through the valves than the round configurations? PM me a price on a set at 17.5-18.5 CR. Weight on these pistons?

 

[juddski88]

Why would it matter? The valves are closed when the piston is close to them, no?

 

[adeso]

I would think the shape would be stronger as an oval since the piston is held by a pin and just b/c the force is even on the top, the force is not transferred evenly. Also, flame propagation and what goes on in chamber is very complex, I don’t really understand it. Changing a piston will change how the flame propagates, but I can't tell you what changes, so I'm curious to learn how much they help flow. I’m going to trust Fingers knows a lot more than me, and needs someone to break a set so he can figure out where the weak area is :woott:

 

[malibu795]

Does this bowl design facilitate a better flow through the valves than the round configurations? PM me a price on a set at 17.5-18.5 CR. Weight on these pistons?

Why would it matter? The valves are closed when the piston is close to them, no?

increased flow would net more air in/out of the chamber during the given duration(low lift area) of the said valve open.. basicly unshrouding the valve more at low lift....end result more power

 

[MarkBroviak]

increased flow would net more air in/out of the chamber during the given duration(low lift area) of the said valve open.. basicly unshrouding the valve more at low lift....end result more power

X2, more power is great but more reliability while making more power is a major deal!