Valve job

[GT2GT4]

I dont know if this is a basic question or advanced because its not a bolt-on..um...thing. oh yea part

anywho, I have noticed that people say 3 Angle Valve job often. what does that mean? what does it do? whats involved?

 

[92redman]

This is probably more of, an uhhhh....newbie question.

An x-angle valve job is just that. X different angles are cut on the top of the valve. It changes the flow characteristics of the head, more angles cut= more power. The most I have heard of is a 5-angle which comes stock on the Viper SRT-10. Apparently they had a few that only got 3-angle jobs and they claimed that made 40hp difference.

 

[1fast97gsx]

I've been thinking about having this done while the head is off ... however I'm hearing some crazy prices ... whats a decent price for a 3 angle and one for a 5 angle? Thanks.

 

[greathuskie]

dont our heads come stock with a 3 angle valve job

 

[zac83]

little secret tip... If you get a valve job - DONT tell the machine shop you want a 3 angle valve job... thats STANDARD at EVERY machine shop in america. They will most likely charge you 50-150 extra simply because you asked for it. If your after a 5 angle or 7 angle job, you better be making some CRAZY power to see any major difference. It's a mod for people with 600+ horsepower with 2000 bucks to spend on a race head.

Long story short: the angel valve thing is a bandwagon, if you jump on it- they'll charge you... if you just say you want a port/polish and valve job, they'll do the same work for cheaper.

 

[Defiant]

^ ^ ^ Bingo. The "best" valve seat has no angles, it's radiused. You get the valves and head away from the machinist before he assembles it, and use Clover Valve Grinding Compound to hand-lap the seats. Then, you _very_very_ carefully smooth back the seat where the valve's not seating, usually using a flapper wheel if you've done it enough before, or just by hand if you've not.
Grinding more angles is an automated move in this direction, without so much hand work and time.
Meanwhile, back here on Earth, three-angle jobs work just fine, and _especially_ on a blown engine. You're forcing the charge in already, it's kinda redundant to "make its path smoother".
But I still recommend hand-lapping. That contact face is the primary path for your valve heads to cool themselves.

Oh, and back to the first question, duh, "3-angle" refers to grinding (or, cutting if it's a nice, modern shop) the valve seat with 3 different stones (cutters): first to cut the actual seat face (45°), then with a more tapered one (30° or so), and finally with a less-tapered one (60° or so). The valves themselves will be ground similarly, but on a valve refacing machine.

 

[JoeZ]

How does the 1g head respond to head work such as vavle jobs and porting? Are there any serious notable gains? Are there any dyno charts or further reading out there?

 

[Suparata]

^^DON'T tell the machine shop you want a 3 angle valve job... that's STANDARD at EVERY machine shop in America^^

You would be surprised to see how many "machine shops" are not doing it right so your post should be "That should be standard" because multiple angles are the only way to locate that .031"of a seat width where it is supposed to be on the face of the valve. http://www.engintecs.com/gallery/album09/5Angles_1
Now how and what those angles/radius are machined does make a difference in performance.

^^How does the 1g head respond to head work such as valve jobs and porting? Are there any serious notable gains?^^

First thing you will see , even after a standard rebuilt that has been done right, is that all the ponies(whatever your engine has) will come back home . For others to join them you will need a performance job done. How many others? Depends on how the job is done and on "What's in your wallet" if you know what I mean.