Can any one tell me what is the purpose of swirl polishing Valves?
Should the swirls be the same for each Valve, or swirl to suit the way the port is entering the combustion chamber?
Should the Exhaust valve be swirl polished?

If you have ever seen the backside of a valve, with it's sharp edge and other impediments to flow you will see how swirl polishing improves flow. I do not think it matters which direction the swirl is.

Vince

Swirl polishing is just the most efficient mass production method to produce a smooth surface on the backside of the valve, personally I turn them on the lathe to cut the backlip. The swirl is just a result of the method and gives no added flow other than sound real nice when you say it.

You can accomplish the same effect with a die grinder and a flat disc against the backside of the valve.

__________________
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But it sound good, so you gotta pay more.

The primary reason for swirl polishing is that it reduces (or eliminates - depending upon who you talk to) the rough surface on the back side of the valve. Rough surface may lead to stress risers and eventually cracks. Therefore, a swirl polished valve is actually stronger that a non-polished valve. The direction of swirl has no bearing at all, just the way the part is manufactured.
A secondary result of swirl polish on the valve is a very slight increase in the flow around the valve. This is a very, very slight increase and probably not even measurable on most flow benches.
As mentioned in an earlier post, most flow improvements relative to the valves themselves are the result of proper (and tedious) blending of the backside of the valve, the seat contact area and the margin (side of the face).

Thanks for clearing that up for me, I thought it might swirl the mixture into the port but if that were the case the swirl should be matched for each port.
The way i see it the Ex back should be polished right up and the In left a little rough.
When back cutting the valve what works best one 30 deg cut or a series of cuts then blending them all together right around to the back face?
I ended up doing that back cut nearly to the margin leaving a little as i read the valve head expands a little pushing the margin back down towards the port.
Then back cut right around to the back of the valve until it was curved then polished it right up.
Any other areas on the valve that should get some attention?

slr6000,
You might be a little confused by the valve terminology, or maybe I am reading your post wrong. The valve margin is the part of the valve head, between the outer edge of the seat and the face.
I only grind one backcut angle and keep the backcut width the same on all of the valves, then blend it with some emery cloth. There are probably some guys who grind more than one backcut angle on the valve, but I haven't seen any flow improvements in doing so. I also grind a very slight break (about .020" wide and 45 degrees) on the face edge of the valve. This gives a suprising increase in flow, especially then the valves are shrouded.

"玉环正祺发动机气门有限公司，玉环正祺动力机械有限公司，发动机气门，气门，汽门 ，进气门，排气门，進氣閥，排氣閥"
I was just gonna say that....

Took the words right out of my mouth. Does that sentence have the word "break" in it somewhere?

No, but I see "stupid Americans" and "profit" several times.

aspirazione，valvole di scarico，エンジン用排気弁，エンジン用排吸気弁，swirl polished valve
yep that clears that up for me, who would have know what goes into designing a vavle for true performance. these guys know there stuff.

What about dimpled valves? Like a golf ball.

"The way i see it the Ex back should be polished right up "

something about exhaust gas reversion back into the cylinder kills performance, might look pretty but I don't think it's worth the work.

"yep that clears that up for me, who would have know what goes into designing a vavle for true performance."

Ford, hollow stems, sodium filled, tuliped heads, too bad they stopped making them.

Interesting, but I would think the labor and time involved wouldn't give you a good return. I don't know of anyone who has done this. Might be like tripping over dollars to pick up dimes. Then again, I might be full of it.

http://www.gofastnews.com/board/eng...dyno-graph.html

http://www.williamsmotowerx.net/valves.htm

Came across this, something to ponder.