[BillyGman]

These are both BBC solid roller camshafts, and both were purchased between 2012 and 2016, (if that matters). The one on the left hand side is from Lunati and the one on the right is from Bullet. The one on the right looks to be made with two different alloys, as though it's a two piece core. But I don't see why it would be, nor how it could be. Can anyone shed any light on this for me? Is the different appearance of the Bullet roller cam on the right any indication that it's made from a different core material? And if so, is that better, worse, or just different?

 

[vortec710]

Is the Bullet cam 2 piece or is the “core” piece just a pressed-insert which could possibly vary by timing gear configuration, etc. Does the “core” piece go all the way thru to the back of the cam ?

 

[1975TypeS-3]

Some roller cams have a cast iron gear pressed on so you can run a normal distributor gear on a steel cam

 

[BillyGman]

Is the Bullet cam 2 piece or is the “core” piece just a pressed-insert which could possibly vary by timing gear configuration, etc. Does the “core” piece go all the way thru to the back of the cam ?

Well that's the back of the camshafts in the pic that you see. But it doesn't look like that in the front, so perhaps it IS just a pressed on iron piece on the outside for the distributor gear like Tom said in post #3

 

[Malibu ss 64]

I guess the bullet is a billet with pressed on cast gear. So no need for bronze distributor gear.
Cant you post a picture of the whole cams showing the journals, lobes and how the cam looks in between.

 

[BillyGman]

I guess the bullet is a billet with pressed on cast gear. So no need for bronze distributor gear.
Cant you post a picture of the whole cams showing the journals, lobes and how the cam looks in between.

Here ya go. The Lunati cam on bottom, Bullet cam on top. The base circle of the Lunati cam is .030" larger, and the the Lunati lobes are also .070" wider than the lobes on the Bullet cam, (I was a little surprised about that. I thought that all the BBC cams would have the exact same lobe width). The lobe width is .550" (Bullet) and .620" (Lunati). As you can see in the first pic, the chamfer on the leading edge of the distributor teeth of the Lunati cam is a little wider. The Bullet cam is slightly used, (about 50 miles and a few runs down the drag strip) while the Lunati cam is new in the box.

In this second pic here below, the Lunati cam is on the right hand side....

 

[Malibu ss 64]

Here ya go. The Lunati cam on bottom, Bullet cam on top. The base circle of the Lunati cam is .030" larger, and the the Lunati lobes are also .070" wider than the lobes on the Bullet cam, (I was a little surprised about that. I thought that all the BBC cams would have the exact same lobe width). The lobe width is .550" (Bullet) and .620" (Lunati). As you can see in the first pic, the chamfer on the leading edge of the distributor teeth of the Lunati cam is a little wider. The Bullet cam is slightly used, (about 50 miles and a few runs down the drag strip) while the Lunati cam is new in the box.

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In this second pic here below, the Lunati cam is on the right hand side....
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The bullet looks like a 8660 billet with cast gear. It has some tracking marks, can you feel them.
Hard to see on the lunati? Is it shiny between the lobes? Almost looks like its not.
maybe 5150 or similar? Do you have the card it may have more info.

 

[BillyGman]

The bullet looks like a 8660 billet with cast gear. It has some tracking marks, can you feel them.
Hard to see on the lunati? Is it shiny between the lobes? Almost looks like its not.
maybe 5150 or similar? Do you have the card it may have more info.

Thanks Marcus. The marks cannot be felt on the Bullet cam. The Lunati isn't shiny between the lobes and neither of the two cam cards have any info about the material. I was just curious and wanting to know how to recognize the signs of certain cam alloy materials. Like I said, both of these cams were purchased over 5 years ago. The way things are now with there being a big shortage on cam cores, I don't even think the cam companies can even offer us any choice of cam core materials. It seems to be you get what you get, ad that's after waiting for at least 6 weeks, unless you choose to pick a generic off-the-shelf catalog camshaft that they've had in stock for some time.

So I kinda doubt that we can even get 8660 billet camshafts anymore. One guy at Howards told me that there's some island off the shore of CA where many thousands of cam cores are just sitting and waiting to arrive at the main land. I asked him why that is, and he said it has to do with all of this covid nonsense and how it has effected manufacturing businesses. I wondered if that Island he was talking about might be Coronado Island,(although that one might only have a military base on it, and not much more).

 

[Malibu ss 64]

Thanks Marcus. The marks cannot be felt on the Bullet cam. The Lunati isn't shiny between the lobes and neither of the two cam cards have any info about the material. I was just curious and wanting to know how to recognize the signs of certain cam alloy materials. Like I said, both of these cams were purchased over 5 years ago. The way things are now with there being a big shortage on cam cores, I don't even think the cam companies can even offer us any choice of cam core materials. It seems to be you get what you get, ad that's after waiting for at least 6 weeks, unless you choose to pick a generic off-the-shelf catalog camshaft that they've had in stock for some time.

So I kinda doubt that we can even get 8660 billet camshafts anymore. One guy at Howards told me that there's some island off the shore of CA where many thousands of cam cores are just sitting and waiting to arrive at the main land. I asked him why that is, and he said it has to do with all of this covid nonsense and how it has effected manufacturing businesses. I wondered if that Island he was talking about might be Coronado Island,(although that one might only have a military base on it, and not much more).

If its not shiny probably not a billet.
I ordered a cam early last year before the covid shit had started. At that time cores was in stock. Talked earlier this year with lunati 8-12 weeks for a 8660 billet with everweargear.

 

[BillyGman]

If its not shiny probably not a billet.
I ordered a cam early last year before the covid shit had started. At that time cores was in stock. Talked earlier this year with lunati 8-12 weeks for a 8660 billet with everweargear.

I could be wrong, but I don't think that Howards is even offering 8660 billet cores at this time. One guy there told me there are no options, and I'd need to use a polymer distributor gear or a brass one. In fact, when I called there to order a custom cam, they took my name and number and had to call me back the next day just so they could "find out if there are any cam cores available"

 

[Malibu ss 64]

I could be wrong, but I don't think that Howards is even offering 8660 billet cores at this time. One guy there told me there are no options, and I'd need to use a polymer distributor gear or a brass one. In fact, when I called there to order a custom cam, they took my name and number and had to call me back the next day just so they could "find out if there are any cam cores available"

I havnt used howard so not sure? Comp, bullet and lunati you can get or atleast could get 8660 core with cast gear/everwear gear.

 

[BillyGman]

OK, yes Marcus, you're correct. I checked with Howards, and from what the guy told me, it sounds like they don't give you the choice of choosing a cam core alloy, but they make that choice. They said that with with the larger solid roller cams which use lobes with respectable durations and higher lifts where they know some heftier spring pressures will be used, ( such as in the 700 to 800 LB open pressure neighborhood) they use a billet core without the customer requesting that. But they also told me that there are two or three different alloys that can be used for a billet core. And it depends on the application as to what alloy will be used.

The example the guy gave me was that a 9310 alloy billet core would only be used for a top fuel engine camshaft where the open valve spring pressures will be in the 1,500 LB neighborhood, but a cam like I ordered which typically be used with an open spring pressure of 800 LBS doesn't need a cam core made with that 9310 alloy. But in that case another alloy would be used for the billet core. Perhaps the 8660 alloy that you mentioned.