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8620 or 5150 or 5160 Camshaft Steel?

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11K views 8 replies 4 participants last post by  CamKing  
#1 ·
8620 or 5150 or 5160 camshaft blank steel? This drew a blank in the Tech Section, so I'm trying it here
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This is a technical question that will require the metallurgists around here to answer.

Crane cams suggested 8620 alloy steel for my camshaft, another vendor suggested the more common 5150 or 5160. I was told the 8620 is better, but when I look at the properties of each steel the 51xx looks better.

What is anyone's background experience with these?
Application is a GM LS2-430 CI road race engine with Jesel 1.8 solid roller lifters and rocker arms. 7/16" pushrods. Manley 221424 NexTex 1.650" Springs at 647 lbs. on All-Pro LSW-1 heads with Titanium intake and stainless exhaust valves.

The camshaft is: 256/270 .738”/.711” 113 LSA +4 advance (with 1.8 ratio rockers)

Give me your insight.
 
#2 ·
In a nut shell the 8620 has a copper coating around the lobes and baked to achieve a even heat treat to all the cam lobes. The others cores are induction hardened which can have a uneven heat treat and possibly make the lobes to hard or to soft. IMO the copper coated 8620 cores is the only way to go. LSM, Cam Motion, and Crane are all good sources for 8620 cam cores for Ls motors. I hope this helps.
 
#4 ·
Both are fine, as long as the heat treat is done correctly.
For our LSx cams, we use either 8660(quench and tempered), or 8620(carborized).
The other key is to make sure you use a core that was roughed in close to the shape you're going to grind on it, so you don't take too much heat treat off of any part of the lobe. Some core companies only have a few roughed in shapes to chose from, so you can really get in to trouble if you have to grind something different. As an example, one of the 8620 core manufacturers only offers one shape for the LSx. It's 245/245 @.050" with .338"/.338" Lobe Lift, om a 114 LSA. If someone tried to grind the cam you want on this core, they would be removing way too much heat treat, and you'd have tracking problems. If I was going to grind the cam, I'd be going with an 8660 core that's roughed at 260/260 @.050" with .400"/400" Lobe Lift.
 
#8 ·
Thank you gentlemen, and especially Mr. Mike Jones. I didn't know about the two heating methods for the two different metals. "8660(quench and tempered) or 8620(carborized)." I would hope all the manufactures follow these rules.