Piston Bowls
- Thread starter Fingers
- Start date
Alll of them so far are going big.
The truck that is coming on line first broke the last set of pistons within 6 hrs of firing the engine for the first time. Ran like hell till......bam.
The truck that is coming on line first broke the last set of pistons within 6 hrs of firing the engine for the first time. Ran like hell till......bam.
I have two sets at this point, first set is going in a sled puller in the 1000hp range and second set is going in Bret's 69 C10 twin turbo LLy that is running 10.7@124mph right now on the stock motor and we are shotting for 9's next season with it and 1000rwhp. I am really impressed with these and can't wait to really show the potential of Jon's work!:thumb:
I'm looking forward to using Jon's pistons. If everything goes good I will have 1000hp with them.
I just like that quote.....
:nothingtoadd:
Except looking forward to seeing how these perform as if they work as expected, being able to take a sane level of abuse (nothing is indestructable) with a large reduction in failures, it will be great for the entire DMax community.
Over 10,000 miles on my set of pistons now. No issues. My transmission, however, is not so happy. 
Something that was bothering me about the FEA was that it showed these, and the stock and the others piston designs failing at lower pressures than I have seen and measured in the real world. I couldn't understand how they were surviving at all. So I used the analysis tool just as a comparative widget so I could see what was better.
Then I stumbled on the issue in my analysis. I was not applying the pressure to the area on the outside of the piston above the fire ring. This turns out to be critical to the piston's strength assessment and, I think, piston longevity in the real world.
Cutting to the chase, this means the pressure differential between the center of the piston and space between the piston head and cylinder wall is THE factor that kills the pistons mechanically. That differential happens when the ignition event is very fast such that pressure does not have a chance to equalize between the center of the piston and the cylinder wall area or when the path is restrictive, like at top dead center when all that quench area is in the way.
Something that was bothering me about the FEA was that it showed these, and the stock and the others piston designs failing at lower pressures than I have seen and measured in the real world. I couldn't understand how they were surviving at all. So I used the analysis tool just as a comparative widget so I could see what was better.
Then I stumbled on the issue in my analysis. I was not applying the pressure to the area on the outside of the piston above the fire ring. This turns out to be critical to the piston's strength assessment and, I think, piston longevity in the real world.
Cutting to the chase, this means the pressure differential between the center of the piston and space between the piston head and cylinder wall is THE factor that kills the pistons mechanically. That differential happens when the ignition event is very fast such that pressure does not have a chance to equalize between the center of the piston and the cylinder wall area or when the path is restrictive, like at top dead center when all that quench area is in the way.
so how did your design and the others do in the FEA with the correct placement of the max pressure?
Mine is still stronger. Not as big a percentage, only 20% -30% Vs 50%.
What I have seen for high end power is about 4,000 to 4,500 Peak PSI Max. I'm sure someone out there has topped that, but that is what I have recorded. The Factor of Safety on stock pistons is about 2.8 to 3.2 or less while with my design it is 3.6 to 4.0 in the same range. That is with an equal pressure between the piston head and cylinder wall. (all stock compression of 17.5:1)
The important thing is how susceptible the stock design becomes to failure if the pressure between the piston and cylinder is not maintained.
Normally, we go out of our way to protect the fire ring from the pressure. As we do that we also increase the pressure differential. What I am seeing is that this will help break the piston.
What I have seen for high end power is about 4,000 to 4,500 Peak PSI Max. I'm sure someone out there has topped that, but that is what I have recorded. The Factor of Safety on stock pistons is about 2.8 to 3.2 or less while with my design it is 3.6 to 4.0 in the same range. That is with an equal pressure between the piston head and cylinder wall. (all stock compression of 17.5:1)
The important thing is how susceptible the stock design becomes to failure if the pressure between the piston and cylinder is not maintained.
Normally, we go out of our way to protect the fire ring from the pressure. As we do that we also increase the pressure differential. What I am seeing is that this will help break the piston.
Just to understand this in a simplier term. Basically the pressure difference between the cylinder and piston vs the the pressure in the piston bowl is a big problem? And that is what is hurting them the most? If so than it would seem delipping is a must to help with it? Because I have seen a few people who don't believe delipping helps.
Sent from my PC36100 using Tapatalk