Join Date: Apr 2010
Location: KY, OH, MICH, FLA, IND
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Swirl aims the intake charge toward / around the cylinder wall, washing the wall down with fuel. Tumble aims the intake charge hitting the top of the piston which churns the charge in a more violent motion. More like an explosion instead of like flushing a toilet.
Depending on combution chamber design valve angles port shape enhances as to how much tumble vs swirl is produced.
Engine like a certian amount of both. Chevy in the past had a bit more swirl than Ford. At one point the early Vortec heads and early Modular Ford engines were designed with high swirl buth had excessive cylinder wall and ring wear. Saw evidence of this in tear down displays in Fords tear down room. Also had a friend the had a engine reman business that was seeing evedence of excessive wear in the swirl port engines.
Ford went almost 100% swirl after that Chevy stepped back to more of a combo in the newer Vortec heads.
On a side note most diesel 4 valve engines one intake valve in connected to a purely (as possible) tumble port the other a dedicated swirl port. Very important as a diesel as there is no plug to fire the mixture.
At one point in a somke break room discussing this with an engineer that was responcible for tear down inspections. I told him he could tell the valve configuration by cylinder wall wear 2 valve ,3 valve, 4 valve. Explaned the patterns our Ford heads made. He thought about it a minite all of a sudden his face lit up and said your right.