VALVE GUIDE BOSS

thanks, i plan on doing a little step by step diy..with pics

If you shape the guide like a fat airfoil facing into the flow through the port you can direct the flow through the center of the port for better flow. If you remove it or leave it round you will have turbulence that will reduce the flow. Just thin it down to a sharp edge on the back side and smooth the rounded front side. I don't have pictures either.

Here Is What I Have Done...sorry About The Late Pics.. I Have Ported A Few E7 With Great Outcome....if Anyone Needs Any Help Or Pics I Will Be More Than Glad To Help brandonhamrick2020@yahoo.com

With A Ported Set Of My Heads And Cam I Picked Up 55hp To The Wheels...base Line Pull Was 188 To The Ground Now 243 Rwhp
Tq Was 233 Baseline And Now 304 Rwtq With Said Heads And Cam..not Bad For A Bone Stock 5.0l Oh It Has Longtubes Too

A quick tip:
Get a couple of allen headed bolts long enough to go through the guide and put nuts on them. That way, you lessen the risk of nicking the tip of the guide when profiling them.
Saw that tip in a book I read a while back on performance engine rebuilding.

The reason why the valve guide boss is like the way it is in the first place to to help draw heat out of the valves and into the water jacket. The less material there is on the boss, the less heat will transfer out of the valves. Too much heat in the valves ( especially the exhaust valve) and they will have a short life.

It works exactly the same way hot/cold spark plugs work. A short plug will run cooler, since more of the plug is in the water jacket. A long plug runs hotter, since most of the plug is in the chamber, and the heat does not transfer out of the plug as quickly.

Shaping the boss is OK, but removing too much material will start effecting the life of the valves.

If your only strip racing, should not be too much of a problem, since the engine block does not saturate with heat, nor does it run for extended periods of time.

Street Strip, your exhaust valves will be burt quickly, depending on how much of the boss is removed.

Also, there is a mechanical stability of the valve perfomance you will loose, and may get end deflection when the valve is not seated.

This will show up on the valve seat in the heads as a mashed appearance on the chamber side of the valve seat surface. Cause the valve is litterally not traveling in a straight line, because of the deflection.

Remember, just cause the boss is removed, you still have the valve shaft itself in the center of the port. The most gain from porting is the de-shrouding of the valve on the chamber side of the heads, and the short turn radius. Port matching is another place where some of the gains are made.

Looking at your photos again. It seems you have not de-shrouded your valves at all. Though you may have, I can not see it in the photos. Big gains there.....

i did not.. that was the first set i did.... i have deshrouded the last five or so sets i have done. it helps alot !

Dont bother to remove the guide boss. It wiill only gain one or two cfm and your valve job wont last long without the support of the guide. There is very little flow in the guide area anyway.

JOE SHERMAN RACING ENGIINES

I know this is an old thread, but I have to comment on one entry. Golf balls are not dimpled to "increase the air flow". They are dimpled to increase lift. The angled club face imparts backspin, the dimples entrain pockets of air that cause the air to move faster over the top of the ball relative to the bottom, creating a pressure differential -- lift. The longer the ball stays up, the further it goes. If you were to suspend a golf ball in a duct (an intake port, perhaps?), and measure flow, it would be worse than if you suspended a smooth ball of the same diameter. Dimpling the internal surface of the port would similarly slow the flow. Surface roughness always increases flow resistance (although in ports, it can have other, positive, effects.) Sorry... I'm a picky nerd.

Originally Posted by DocHawk

I know this is an old thread, but I have to comment on one entry. Golf balls are not dimpled to "increase the air flow". They are dimpled to increase lift. The angled club face imparts backspin, the dimples entrain pockets of air that cause the air to move faster over the top of the ball relative to the bottom, creating a pressure differential -- lift. The longer the ball stays up, the further it goes. If you were to suspend a golf ball in a duct (an intake port, perhaps?), and measure flow, it would be worse than if you suspended a smooth ball of the same diameter. Dimpling the internal surface of the port would similarly slow the flow. Surface roughness always increases flow resistance (although in ports, it can have other, positive, effects.) Sorry... I'm a picky nerd.

OK picky nerd...

You mean to tell me the ball spinning backwards will in effect throw a trail of air over the top of the ball, thus giving it essentially more lift from the increased flow over the top (like a tire flinging water behind it and it will throw the water forward also)? Is that how the dimples work? They grab the air with it's spin and fling it over the top?

I gotta learn to control my Gate! I leave it open too much and I slice right. But when I close it too much i go straight... But closing my gate feels funny and my swing is inconsistent...


Never mind I got off topic...