Billet Roller camshafts?

la360 · Post by **la360** » Fri Dec 17, 2004 4:46 pm

Does anyone know what materials are used to make the billets for Roller camshafts? I am also curious about what hardening is done, and the process they are machined in, e.g - Are the profiles rough ground before hardening etc. I have been a CNC Machinist for the last coming up to 10 years, so it's more so to satisfy my own curiousity, I am not planning on making any anytime soon, lol
Whilst we're on the subject, generally speaking, how deep in the hardening on a Comp Cams Roller? I have one here I would like to reprofile, and about 20-30 degree's of duration @ 0.050" needs to come off it.
Thanks guys
AL...

CNC BLOCKS · Post by **CNC BLOCKS** » Fri Dec 17, 2004 5:34 pm

Most rollers are built out of 8620 billet material and I beleive that the cores are heat treated before finish grinding as to save time and some cores that comp cams has for flat tappet use are rough ground and heat treated. To grind a roller core for flat tappet use you would go through the heat treating.

bill jones · Post by **bill jones** » Fri Dec 17, 2004 6:11 pm

-I've had a variety of roller cams reground and from my experiences I wouldn't regrind more than just a few degrees.
-Typically the cores are something like 60rc and I've checked every cam before and sfter regrinding and they lose about 5 points of hardness so that means they end up around 55 or so.
-I had a stock GM hydraulic roller reground to get 10 more intake duration and to narrow up the lobe spread from 115 to 111 and that thing went from 58rc to 52, but it didn't appear to be a problem in a 5000 max rpm marine application.
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-If you were to widen the lobe spread (and reduce the duration at the same time) during regrinding you could take metal off the "down" side of the intake lobe so that would be quite so bad having the softness there as apposed to taking the precious metal of the "UP" ramp.
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-The way I hear it, the cams are preground to pretty close to the final specs, left just a little large so that the cam can be straightened after the heattreat process, then they are finished ground to size.
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-I have had one new cam that was too soft to start with, had it heat treated and then just retouched up the existing lobe profiles slightly and the surfaces show surface cracks sort of like a dry lake bed.
-I chose to not use that cam because of that, unless I could run it in an engine of my own where I could keep track of what happens.

la360 · Post by **la360** » Sun Dec 19, 2004 6:44 am

From what I have been told, if you try to remove too much material too quickly when grinding the camshaft, cracks like you are refferring too can result. I will have to speak to my local camshaft grinder regarding reprofiling and rehardening my Roller. I have had no luck in trying to sell it over here in Oz, so it's my only real option , other than using it for a door stop. Thanks for the replies guys, you have all been quite helpful.
AL...