Digitizing Cylinder Heads Help

[SBillinson]

Originally Posted by Kevin Panzino

Not going to get involved with the side discussions regarding NHRA checking stocker heads with a device, nor the NHRA /IHRA discussion.

But I can tell you from being in industry, the level of detail that the modern laser scanners and/or a 5 axis CNC mounted digitizing probe, and the software that goes with it is at a level that blows your mind. As long as the laser/probe can get to everything, it will create a model of the shape that is within at most .001" and in most cases better than that.

What I always wondered about, is just how repeatable the castings are/core shift etc,

Certainly a major issue on the old factory castings, but just how good are the new approved aftermarket heads on core shift?

I have to think a scanned, max-effort head that someone spent a ton of time on, one port at a time, and checked along the way with a UT device and got to min wall at a few places wouldn't then break into water and create more than a few boat anchors when that program was run on a new head ??

Kp

Core shift on new casting should be much better today than even 20 years ago, but I expect it depends on the foundry and it's location. I typically sonic check before I start grinding. Then again, I've gotten pretty good at heliarcing in confined spaces....

I think material purity and porosity are probably of greater concern. When the Ford D3 Cup heads first came out (early 2000's), they had a tendency to fail at the rocker are pedestal mounts. Those were one-piece pedestals for all 8 valves subjected to relatively low open spring pressure. The top of the head would come undone. They fixed the problem--which I understood as a porosity issue--in later castings.

I've struggle mightily with porosity issues, both aluminum and cast iron (especially the old stuff). It's a nightmare.