By placing the dish directly over the combustion chamber of a wedge-type head, the quench area is maximized and the flame front may have less distance to travel than if a round dish piston were used. But this is generally only used if the compression ratio would be too high if flat top pistons were used. Also, instead of machining flat tops into an inverted dome piston, a D-shaped dished piston is usually used. Not quite as good as a true mirrored dish, but close.I have heard of people doing this on their pistons. What is the bennefit of this modification? How much do they mill out of the piston. (Depth)
Pistons have been custom machined like this since the beginning. The main caveat is the thickness of the piston deck has to be sufficient and the balance needs to be corrected.You cant modify pistons in this manor you need to buy them forged or cast in the proper shape.
Polishing the chambers and piston tops is a waste of time on a street engine, the chambers and piston gets a carbon coating the first five minutes the engine runs.Maybe I missed something but exactly how do you get the "mirorred" finish?
I'm getting a bit tired of correcting you. Have you ever even opened up an engine?? There is carbon almost the second you start the engine the first time- polishing chambers is a total waste of time for him.You polish the pistons with a bench grinder that has longer shafts for a large polishing cloth wheel. Heads can be done with a diegrinder/dremel but it will take forever.
Polishing on the street is not needed. But is not effected by carbon for two reasons. One the carbon does not stick to the polished surfaces, two the polished surface still reflects heat even if it cant be seen. This is way home insulation has reflective foil backing and is never going to see any light because its buried in the ceiling and under the roof of the house but still reflects heat back into the house.
This will help on any engine street or race but usally time consuming and if your not doing the work your self you will have to pay way to much to have it done. If you got the time it doesnt hurt.
Only forged pistons can be machined with little impact on the strength. This is only becasue they are way stronger than most apps can use. But if they are borderline in strength and they are cut they will fail for sure. Also cutting the piston head tends to allow the head to collapse and expand at different rates from heat and casues issues that buying pistons cast in the correct shape is always the way to go.
Hyper, and cast iron pistons can not be but they will fail. They are sometimes cut to reduce compression but this is done to engines that make 200hp not 500. So once you think about your goals and you will be buying the correct pistons and go no need to cut them at all.
A LOT of misinformation gets repeated by people w/no real experience. They google something, and then repeat it thinking that no one realizes they're not speaking from experience. But resisting carbon build up isn't the issue, anyway. The issue is whether there's any real benefit or not to YOU.Cobalt327 you might want to go scroll on some other forums, cause I believe there is some schooling needed to take place. Haha a few others are under the impression that a polish will resist carbon aswell.