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Another Comp Cam eats it...

Old May 13, 2015 | 04:02 AM
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I will add, the picture doesn't show the disturbing part. A lot of the 90 degree edges on the cam (the lobes in particular) have random pitting/chipping. These are non-contact surfaces, so this indicates corrosion or stress fractures. There's no rust and it looks like a crappy machining job, except when the cam was new all the edges were razor clean.

So I will hold to my original assessment, the cam was a crap blank from Comp when it was made. I don't have the $$$ to get it sent through a metallurgical analysis right now, but I can't imagine the results would be much different from what I know now.
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Old May 13, 2015 | 10:31 AM
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Originally Posted by TX Tahoe Z71
Man. I have 30-40k miles on my cam, makes me nervous. But I have to think this is a 1 in 500+ occurrence, I'd speculate that if it were more, it would be all over the forums (this is the first I've come across it in my years on the forums).
This has been all over Ls1tech for the last couple of years. Seems like every month another couple come up.
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Old May 13, 2015 | 10:59 AM
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Do you know which lobes you had and which springs you were running?
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Old May 13, 2015 | 03:57 PM
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Originally Posted by gagliano7
This has been all over Ls1tech for the last couple of years. Seems like every month another couple come up.
You're right, did some reading, seems not to be so uncommon
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Old May 13, 2015 | 09:14 PM
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The thing that really has me wondering is that the cam wears and the lifters don't. There is much more surface area to the cam than there is the lifter, and the lifters never wear and the cam always does. There is just as much pressure up on the lifter as there is down on the cam. I can't believe that they are properly heat treating the cams before they leave.
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Old May 13, 2015 | 09:33 PM
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Originally Posted by Gadgetized
The thing that really has me wondering is that the cam wears and the lifters don't. There is much more surface area to the cam than there is the lifter, and the lifters never wear and the cam always does. There is just as much pressure up on the lifter as there is down on the cam. I can't believe that they are properly heat treating the cams before they leave.
The cores are already heat treated prior to grinding them to spec.
The main journals are ground after heat treating.

If you heat treat again after grinding the lobes, it will distort the cam shaft.

Comp does not stock the LS cores. They buy them from other vendors in the industry who do depending on demand and grind as needed.
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Old May 14, 2015 | 04:05 PM
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I didn't know that, I assumed they were heat treated after they were cut. Good info.
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Old May 14, 2015 | 04:52 PM
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Originally Posted by Vortec350ss
Do you know which lobes you had and which springs you were running?

I was running TEA dual valve springs
for .650 lift. Here's one that broke a while back:


Here's the cam sheet:


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Old May 15, 2015 | 12:30 AM
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That lift looks pretty aggressive for the duration. How much open spring pressure was it running? Could be a hardening problem, too much spring, too aggressive of lobe, or combination of the 3. Just pulled down my Nova engine to freshen after 3 years and my 218/.570 JFR/Isky is in perfect shape.
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Old May 15, 2015 | 12:46 AM
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Those look like the EPS lobes... Oy...

The EPS lobe is fairly similar to the comp LSL from what I can tell. For what its worth Tooley loves the LSL. Its the intake lobe on almost all of his cams.
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