Do you know what the process is and what it does?

TIA

 

People often do this to change the combustion characteristics (speed or completion of burn), or to increase compression. You don't need to to it, especially on a turbo car. In most cases these days, people choose to get different pistons to change compression, rather than have to weld up and machine a head that could crack while welding. There may be other reasons somebody may chime in with though.

 

Thanks for the quick reply!!!

How does this process compare to polishing the cobustion chambers (as far as flow and combustion characteristics go, not raising the comopressoin)?

TIA

 

I guess that polishing the chambers will have some effect on the burn, but personally, I'm not going to work my *** off for hours trying to get that last .05hp out of my engine. There's better ways to spend your time.

 

I had this done on my KA24E (nissan) sohc head to raise compression, as it's a 3 valve per cyl head and the spark plug is offset next to the exhaust valve, i had the extra material added in behind the plug.

IMHO it really wasn't worth it, you are only better off reshaping the chamber in a 4 valve per cyl head to give it a more pronounced clover leaf shape to increase the "squish" area; both to raise CR slightly and help reduce detonation.