LS1 Block Material
As for the alloy talk...I did a lot of work with GM's castings in school for metallurgy research, but I'm not allowed to talk about them. I can say that they put a LOT of research into the production alloys to save money and have a good product (for their intended use).
Matweb is a pretty good resource to look up properties on the alloys mentioned in this thread.
To each their own.. Everyone has an opinion just like an.......
To each their own.. Everyone has an opinion just like an.......
You brought up a good point yesterday and I didn't see a need to restate that point today. It's time to let this go and move on.
It appears that people in general are just trying to get this thread back on track and I believe that that is the business at hand.
Regards,
Steve
makes sense, cam lobe surfaces need to be hard, but the shaft must not be brittle (even on the surface) or it would crack/split/break.
Yes, carburized 8620 makes an extremely good wear surface (cam lobes). The core hardness even under the Cu masking is high enough to impart very good strength and some ductility to the cam. You get many of the same characteristics by induction hardening the lobes of a 5150 core which is direct hardening and doesn't need many hours in a carburizing furnace. Metallurgists could probably argue which is the better method, but for most applicatons, either is usable.
IOW, with today's outrageous copper prices and the cost of the energy to carburize to the required depth, 8620 cams are becoming rarer. The material cost and machining/grinding costs are pretty much a push for either material, so it is most likely energy (heat treating) and copper costs which are driving steel cam production. It might make cam manufacturers look fondly on the days before rollers, where all flat lifter cores were cast.
I still like built-up cams which some OEMs use. You get to choose different materials and heat treatments for the shaft, gear, bearing journals and lobes. The capital equipment cost is excessive for an aftermarket cam application, but I wouldn't count it out in the future.
This is probably a thread hijack because it doesn't relate to the OP's topic. At least it's technical.

Jon
The Best V8 Stories One Small Block at Time







