BigBake

It comes stock on a factory LS1 style head, I don't know how much more street you can get than that. You are correct that the airflow dictates the use of such small details.

ritz

We all know LS1 heads > *

Hell LS1's in general > *

Corey

They did it on nearly all their heads. The shop was not a performance shop. The did do some performance work (porting and sleeving)

It had been open for 80 years when I started working. Two of the machinists had been there for nearly 40 years.

MGBRaceman

Something interesting that I've never seen before, Z1 motorsports offers a rediculous 14 angle radius cut valve job on their stage 4 motors, here's the link... http://www.z1motorsports.com/product...products_id=58

HatefulMechanic

GM started using it on production heads on the Vortech's in 94+, i figured they would use it on the LS's.


damn. my shop does a standard one angle on most unless i ask

unless they have changed their machine shop, which i think they did when they went to their new facility, i have seen quite a few problems with their engine work. again, i think they changed though, so i might be wrong on it.

mike93108

Royalty,
Since no one really answered your question properly, I joined this site to help out.
This is what a 3-angle valve job is....

A 3 angle valve job is the process of machining the contact area of the underside of the valve, so that the mating surface is smaller or sharper, and making the seat angle greater. This allows the valve to seal faster and more tightly. This also increases port turbulence, which increases air speed, allowing more air into the mix.

One reason why it is important to have a good machinist is that by changing the angles and size of the valve contact patches, you can change the “agressivenes” of the valve job. A more drastic valve job will have higher gains, but at a cost. Valves dissipate heat during their closed state. When the valve is closed, it is in contact with the cylinder head, and the heat is transfered. This issue with heat transfer is why titanium valves were introduced. Titanium valves provide ultimate thermal protection, and decreased maliability under stress.

Another thing to consider when doing any kind of cylinder head modifications is that entire valve train is designed to work as a system. The tolerances, valve lashes, spring tensions, etc, are all designed so that everything runs on harmony. When changing any part, you need to be careful and make sure that everything is compatible. I personally recommend the all or nothing approach. Many street cars will be just fine with stock head work. If you’ve got a spare head, and want to bring your car to the next level, i say go for it. But you can’t just throw in super aggressive cams, or get a 3 angle valve job by itself.

The best thing to do is make friends with a local machine shop. They will have more knowledge than you will know what to do with!

Hope this helps.

Be fast and true,

Mike

Fabrik8

I know this is a thread bump from 2005, so I'm closing the thread but leaving the post intact for now if someone can get some knowledge from it. Normally that would get an infraction or warning for bumping a 7 year old thread.

Fabrik8

Oh, and titanium valves aren't used for their "ultimate thermal protection". They're used for their low mass. There are much better alloys for difficult thermal problems. There are special high temp Ti alloys, but they're used for the combination of weight and decent temp characteristics, not temp characteristics alone. There are a lot of nickel-based alloys with higher temp resistance.