Heads Question

[Gauvin007]

Just a quick question. I was looking in to Porting and polishing my heads over the Winter. And i was reading up on it and i saw something about 3 angle Valve job. What exactly is that? Also If i do heads intakes and a cam how much HP do u think i can gain?

[malice10985]

The 3 angle valve job helps the valves seal better.

Normally, a small amount of your combustion charge leaks out of the valves and goes into the intake/exhaust tract.

The 3 angle job prevents this.

Why didn't they do it from the factory? It requires precision machining and our heads are mass produced. It is not cost effective for GM to do this type of headwork for such marginal gains in power.

[jonny985]

Stock heads already have a 3-angle valve job. Almost every company nowadays does this from the factory. However, they don't pay as much attention to detail as a performance company would if you were to have one done at a quality machine shop.

The valve seat also gets messed up over time and a valve job is often necessary to return the heads to good flowing condition.

[WickEdSix9838]

<blockquote>quote:</font><hr> The 3 angle valve job helps the valves seal better.
Normally, a small amount of your combustion charge leaks out of the valves and goes into the intake/exhaust tract.

The 3 angle job prevents this.

<hr></blockquote>

both of your guys replys are a little off, the 3 angle valve job has no more sealing than a stock valve job, the 3 angles make the heads flow more, if the angles, length of hte angles, etc are right, most of the serious race head shops have 5 angle valve jobs, and a radiused exhaust valve job, my dad has been R&Ding on valve job angles for a long time(being that he ports head for a living) and has one that has picked the flow of heads up as much at 15 cfm w/a valve job alone...and you have to re-valve job a set of run heads because the seats get beat up overtime adn need to be re-trued up so they can seal properly...

[ October 29, 2003: Message edited by: WickEdSix9838 ]</p>