Kip Fabre

5150, 8660 & 8620 cam cores, what is the difference and which is best? We will break it down with this simple explanation.

5150 Induction Hardened Chromium
5150 is the standard camshaft that most all of our competitors sell. This alloy is induction hardened. While it is not the best available, it is perfectly fine for most applications if proper care is taken to finish the lobes properly.

8660 Induction Hardened Nickel-Chromium-Molybdenum
8660 cam cores have a superior alloy to the 5150 and are induction hardened. This is a step up over the 5150 cam cores.

8620 Carburized Nickel-Chromium-Molybdenum
Our 8620 camshafts are made of a superior alloy to the 5150 and these cores also endure a more involved oven hardening process. This hardening process creates more durable wear surfaces on the lobes while maintaining the desirable ductility characteristics of the the 8620 alloy. The final product is a camshaft that is stronger with a more durable wear surface. Our 8620 cams are a superior product.



Because we know that, for some enthusiasts, pricing is a major factor in choosing parts, we now offer all 3 cam core options. This is an extension of our commitment to make sure that our LS customers can get exactly what they want in a camshaft.

Our pricing for these 3 different cam core choices from Cam Motion is as follows:
5150 $399.00
8660 $425.00
8620 $449.00

atljar

A touch over 10% difference in cost, sign me up for the good ones

[Cerberus]

Is the only way to tell the copper coloring between the lobes and the price?

My cam card print out said core 3310108, which I just assumed to be just a rough machined blank to make final grinding faster for customers.

Kip Fabre

The copper cores are 8620. The 3310108 is one of the 25 different cores we make for the LS. This core would be the closest to your finish grind so only a small amount will be taken off that core for finishing. Maintaining maximum hardness depth.

SHovV

What kind of cam determines the core you guys use?

Martin spec'd me a solid roller for my LS7 through you guys and it appears to be the 8620 core. I also noticed it's a solid core, unlike the hollow core I got from Comp.

Is this to keep the cam stiffer and reduce flex with higher spring pressures?

Kip Fabre

The 5150 hollow core are fine for street performance and some track use. GM made the core hollow to save little weight. One of the problems with these cores is they will only take about a .440 lobe lift and that is pushing it because you get close to the barrel of the cam with the base circle when grinding for higher lifts. The 8620 cores( Aircraft Quality Steel) we make are solid so we can put up to a .505 lobe lift on the core without going into the barrel. The heat treating process with 8620 is a better process than the induction harding process for the 5150 cores. As for the stiffness they are the same because one is hollow with a larger diameter barrel and the other is solid with the smaller barrel. They are the same stiffness.

double06

So since we have a 1.8 rocker on LS7 and usually a max .660 lift (most of which is limited by spring) results in like a .370 cam lift which is below the .440 number we should be OK. If we wanted like 800 or 900 lift that is where the problem arises. The hollow core is the same a driveshaft principal, the large the diameter of the tube the greater the strength and thus less need for metal thickness.

Kip Fabre

That is correct.