Piston Bowls
- Thread starter Fingers
- Start date
I think you need to look alot at what type of builds go on. Not everyone uses stock cut and coated pistons. I am talking high compression. Not stock compression.
jon, sorry for this bit off OT but how do you feel about
lb7 pistons
stock (not delipped) coated V.S. delipped and coated?
lb7 pistons
stock (not delipped) coated V.S. delipped and coated?
The oval shape is still worrying me if your injector sprays a circle wont 1/3 of your fuel miss the bowl completely and just spray on top during compression I hope it works out and you do something amazing but diesel pistons have had a round bowl for many years for a reason
He said the smallest dimension of the oval is still the same diam as the stock diam iirc. So, it will spray into the bowl as much as it would on a stock piston on the short side & have even more bowl to spray into on the long side.
That's my understanding of his explanation. Hopefully he'll clarify that detail.
That's my understanding of his explanation. Hopefully he'll clarify that detail.
That's what I thought he said as well. Should be interesting to see how it works.
I hope it works 18.1 will be awesome if it will hold up it gets my vote on making more power I will gamble on the bottom end.
This is a spin off from another thread.
I am nearly done with my piston bowl design and hope to cut the first one this weekend. I have used a FEA program to try and refine what I think is a reasonable compromise that does not require a significant reduction in compression ratio.
For background, here is the analysis of a stock LLY piston showing where the stress exceeds the strength of the material.
And here is a delipped piston under the same load. Note that it is NOT stronger than the stock piston.
Here is my latest design:
This maintains the stock compression ratio leaving some room for valve relief cuts if need be.
IF the FEA can me trusted, the design is 50% stronger than the stock configuration.
The cast pistons have a steel band embedded in them which I need to miss for the new design. So wish me luck when I cut the first one since I don't know exactly where it is on the blanks I have bought for this project.
Besides the "fea" saying so, How do you explain the oval being stronger
Vs a circle?
Is it just making it stronger in the weakest part of the bowl? Or what is your thought on this?
not dissn just always under the impression that circles would be stonger?
thanks simon
I'm fighting the CAM program I'm using to generate decent NC code for the mill. I'm thinking I might have to go back and hand code the mill paths.
The minor axis of the bowl is the same as the stock piston's chamber diameter. Shouldn't piss over the top more than the Stockers. The major axis is a lot bigger and should be an improvement.
The load being transfered to the pin is not circular.
All the oval does is allow me to put more material where there is more stress.
On the bright side, the block is about ready to go to the machine shop.
The minor axis of the bowl is the same as the stock piston's chamber diameter. Shouldn't piss over the top more than the Stockers. The major axis is a lot bigger and should be an improvement.
The load being transfered to the pin is not circular.
All the oval does is allow me to put more material where there is more stress.
On the bright side, the block is about ready to go to the machine shop.
I'm fighting the CAM program I'm using to generate decent NC code for the mill. I'm thinking I might have to go back and hand code the mill paths.
The minor axis of the bowl is the same as the stock piston's chamber diameter. Shouldn't piss over the top more than the Stockers. The major axis is a lot bigger and should be an improvement.
The load being transfered to the pin is not circular.
All the oval does is allow me to put more material where there is more stress.
On the bright side, the block is about ready to go to the machine shop.
If you'd like, I can help?
What Cad are you using I cant see why it would be hard? maybe time to upgrade to better software.
Yea, time for a new CAM suite.
Been using MasterCAM, but never did much NURBS stuff. I'll see what their latest and greatest has to offer as well as others.
Been using MasterCAM, but never did much NURBS stuff. I'll see what their latest and greatest has to offer as well as others.
thats what the '+' was for. there will be a time when the compression will peak in efficiency and the cons will outweigh the pros.