Welding pistons
- Thread starter SoDak24valve
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Fahlin Racing
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Yeah, don't doubt it. Renopker, whats your view on this subject?
renopker
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I stay out of these theory debates because looking threw a microscope wont always give you the full picture.Combinations no two the same yet still the same results. We have welded pistons changed bowl design but this on Super Stock tractors were max fuel and air and timing are more of a bulk issue. SS tractors are more of a top fuel thing then a Pro stock car thing. However I do like to follow COMP461 views.
SoDak24valve
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I don't have a set cc's for the bowls yet, there are lots of factors like which have all been stated in this thread that I will need to figure in I know. I am still looking at the shallow and wide bowl design which seems to be overall the best design so far. So I guess I am still just waiting to decide on what's going to get me the most out of my set up.
Fahlin Racing
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True, in depth pieces should be discussed in more than one area though when needed then we backup and adjust things to mold what we have. Any engine out there, if we don't get a good performing head there is still a chance that we have power on the table regardless of boost or N/A.
COMP461
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I have been involved in process engineering of high performance engines for the last 30 years.
The secret to this is to never believe any part of your programs is total right, or totally wrong. Think outside the box, and look at every component as changeable. Never say “that will not work “.
Just because something didn’t work in the past doesn’t mean you had it right back then. When you change components go back and revisit you past hunches and failed ideals
I can name many examples of this. The gains we are now making in advances valvetrain components, were not even possible 10 years ago, or even 5 years ago.
Now to another part of engine development, you are not going to get it entirely right, or wrong the first time. It’s a slow and methodical move that never ends .
Now to my beliefs on pistons.
First the flatter the pistons and higher the compression the more you will exchange exhaust gasses for incoming charge air. There is a limit to compressing, but I see it is somewhere north of 20 to 1.
You cannot just raise compression in itself. First you must have active control of timing and fuel delivery, so as to get around the destructive lower RPM torque curve.
Torque is easy to make, ask any first time diesel truck owner with a tuner. You can make enough torque to destroy a engine and drive line with just the push of a button.
Hp is and always will be the only goal of engine development program from Indy car to 2.6 sled pulling. This is set in stone, and if you don’t understand this, please stay out of this discussion.
With higher compression you must look at the effects on turbine wheel and exhaust housing selections. Higher compression allows looser selections and allows the chargers to work more efficiently.
Cam design . I have been working with racing cam development for most of my 30 years in racing engine development. The first thing you need to forget in cam design is forget these words Duration, Overlap, Centerline, and Lobe separation angle. We open the exhaust valve at a given point, in turbo diesels, we look and more than just cylinder blow down, but its effect on the turbine wheel.
Second we look at where we close the exhaust valve. In turbo diesels where you have pressure in both exhaust and intake track, you do not want both valves open at the same time. There is no cross flow scavenges, repeat there is zero cross flow scavenge. If you have both valves open at the same time, and the piston is receding down the bore you have created a low pressure area and exhaust gasses will reinter the combustion chamber
Anyone that believes that a 106, or 108 LSA will work no matter what the size of the intake and exhaust events is just horribly misinformed.
The intake valve in this deal needs to open as soon as possible after the exhaust valve is closed , simple
Not to the most critical and most controversial part of cam timing event design , where to close the intake valve.
I have been deeply involved in finding the place to close the valve. All of this is taking in to count the RPM level you are running the particular engine program Close the intake valve too soon and you stop the flow of air charge in to the chamber. Close it too late and you get reversion.
None of this takes in to count the design of the lobe itself, the lift, ramp rates, jerk and many other aspects that make me work my math skills every day.
The secret to this is to never believe any part of your programs is total right, or totally wrong. Think outside the box, and look at every component as changeable. Never say “that will not work “.
Just because something didn’t work in the past doesn’t mean you had it right back then. When you change components go back and revisit you past hunches and failed ideals
I can name many examples of this. The gains we are now making in advances valvetrain components, were not even possible 10 years ago, or even 5 years ago.
Now to another part of engine development, you are not going to get it entirely right, or wrong the first time. It’s a slow and methodical move that never ends .
Now to my beliefs on pistons.
First the flatter the pistons and higher the compression the more you will exchange exhaust gasses for incoming charge air. There is a limit to compressing, but I see it is somewhere north of 20 to 1.
You cannot just raise compression in itself. First you must have active control of timing and fuel delivery, so as to get around the destructive lower RPM torque curve.
Torque is easy to make, ask any first time diesel truck owner with a tuner. You can make enough torque to destroy a engine and drive line with just the push of a button.
Hp is and always will be the only goal of engine development program from Indy car to 2.6 sled pulling. This is set in stone, and if you don’t understand this, please stay out of this discussion.
With higher compression you must look at the effects on turbine wheel and exhaust housing selections. Higher compression allows looser selections and allows the chargers to work more efficiently.
Cam design . I have been working with racing cam development for most of my 30 years in racing engine development. The first thing you need to forget in cam design is forget these words Duration, Overlap, Centerline, and Lobe separation angle. We open the exhaust valve at a given point, in turbo diesels, we look and more than just cylinder blow down, but its effect on the turbine wheel.
Second we look at where we close the exhaust valve. In turbo diesels where you have pressure in both exhaust and intake track, you do not want both valves open at the same time. There is no cross flow scavenges, repeat there is zero cross flow scavenge. If you have both valves open at the same time, and the piston is receding down the bore you have created a low pressure area and exhaust gasses will reinter the combustion chamber
Anyone that believes that a 106, or 108 LSA will work no matter what the size of the intake and exhaust events is just horribly misinformed.
The intake valve in this deal needs to open as soon as possible after the exhaust valve is closed , simple
Not to the most critical and most controversial part of cam timing event design , where to close the intake valve.
I have been deeply involved in finding the place to close the valve. All of this is taking in to count the RPM level you are running the particular engine program Close the intake valve too soon and you stop the flow of air charge in to the chamber. Close it too late and you get reversion.
None of this takes in to count the design of the lobe itself, the lift, ramp rates, jerk and many other aspects that make me work my math skills every day.
Last edited:
Fahlin Racing
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Snap, crackel, pop and jerk. Never understood those slang terms and probably never will but am aware. Can;t recall if that was Crane or Isky who used those. Seems the crown will be working with not just the valve pockets but the portions a bore shrouded valve just so happens to have. With a deep bowl it could be said the crown design hinders (to a point) or works against fluent flow patterns to allow thorough combustion, where which you have stated flat crown with shallow setups employ a more direct path allowing the blowdown to drive our turbine wheel more easily I suppose Greg.