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out of work hair dresser
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Worst lobe shown in pics. Others are following suit. Lifter rollers appear as if the "chrome" is flaking off as it's the polished hardened surface actually leaving the scene.

Why?
 

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out of work hair dresser
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Discussion Starter #3
All new, less than 2000 miles.
 

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All new, less than 2000 miles.
Have seen similar in racing applications where there was not enough seat pressure. It caused valve bounce at closing and hammered the lobe up the ramp an over the nose. Loose axles were always and indicator that this was the problem. You may have something else going on.
 

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out of work hair dresser
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Discussion Starter #6
The largest problem is the lack of a definitive answer. This type of cam/lifter fail is abundant and can be seen/found all over the internet. Along with those is lots of different opinions on the cause(s). The most aggravating part of this is more than likely there is, in fact, different causes with the same ending result. This is the first time I've encountered such in a new engine and naturally would like to know "why".

It's an LS2 street engine, Comp Cam XER lobes, OEM LS7 lifters, 150 seat/460ish on the nose. Aftermarket oil pump, good pressure all around, high zinc/phosphorus oil with ZDDP additive to boot. I have my own theories but they are just that.
 

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One thing we have learned from our circle stuff, is that the roller motors dont tend to like the zinc. The roller doesent roll, it kind of slides. I have seen this happen with to small of a cam core(ended up breaking a lifter in half) but other than that I would be inclined to fault the seat pressure. Any other details about the valvetrain? rocker setup, valve weight, stem clearence, etc?
 

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nevermind....I was posting while you posted and see the info up above.

What rpm and what cam specs?

The lifters are what I blame here. Even if it turns out that they werent the problem, they are the weakest link in the equation, which is why I gravitate that way.

The lifter types, such as the OEM LS7 lifters with the captive/encapsulated lifter wheel dont like a heck of a lot of abuse.

thats a fair amount of spring to make them live with, and if the lifters themselves didnt give up....I cant imagine it would have been super long before they did(even without any valve float issues)
 

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The largest problem is the lack of a definitive answer. This type of cam/lifter fail is abundant and can be seen/found all over the internet. Along with those is lots of different opinions on the cause(s). The most aggravating part of this is more than likely there is, in fact, different causes with the same ending result. This is the first time I've encountered such in a new engine and naturally would like to know "why".

It's an LS2 street engine, Comp Cam XER lobes, OEM LS7 lifters, 150 seat/460ish on the nose. Aftermarket oil pump, good pressure all around, high zinc/phosphorus oil with ZDDP additive to boot. I have my own theories but they are just that.
Wow, that sucks. If the lifter's axels are "tight" It's probably material, lubrication, or hardness. In other words, a quality control issue.
 

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The largest problem is the lack of a definitive answer. This type of cam/lifter fail is abundant and can be seen/found all over the internet. Along with those is lots of different opinions on the cause(s). The most aggravating part of this is more than likely there is, in fact, different causes with the same ending result. This is the first time I've encountered such in a new engine and naturally would like to know "why".

It's an LS2 street engine, Comp Cam XER lobes, OEM LS7 lifters, 150 seat/460ish on the nose. Aftermarket oil pump, good pressure all around, high zinc/phosphorus oil with ZDDP additive to boot. I have my own theories but they are just that.
I had this happen to a hydraulic roller on me one time. Sent cam back to manufacture and they sent me new cam. I didn't change anything including lifters and this new cam was fine! Mine was a hardness issue! You shouldn't need ZDDP additives with that spring pressure. I had 200 on the seat with emission 10w30 oil.
 

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Wow, that sucks. If the lifter's axels are "tight" It's probably material, lubrication, or hardness. In other words, a quality control issue.
That was my thought.... check out the case depth
 

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Butch
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I had an issue with a 8660 core, the cam grinder stated there are 2 lobes which are the "master lobes" and the dowel key is off, enough to make the intake center line be 8° to 12° off, and at that time a guy did a big block on another forum and it was 13° off and hit the valves and messed up his new AFR heads (Didn't degree it)

I asked why they were off, the dowel is placed incorrectly, and if they ground the camshaft so it was accurate off the dowel, many grinds would leave minimal hardness or grind through the hardness, so they grind off the master lobes thus the dowel being off 5° or a more, making the intake center line way off

They took the camshaft back from me, and ground it on an 8620 core I had, was perfect. Since the issues with those cores, and Crane had just closed around that time thus hard to get the 8620 core, I started using the SA Gear timing set as it has an adjustable cam gear that adjusts like a Jesel belt drive

That was my thought.... check out the case depth
X2, I believe he will find an issue here
 

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The issue with this case is going to be with the lifter, not the camshaft. I think it's either a hardness issue with the roller, or incorrect alignment of the lifters due to the lifter
retainers/guides. I have a pile of LS camshafts and lifters that look just like this. Some I related to the lifter guides, and others had no apparent root cause.
 

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Billy, I'd almost want to have our heat treaters cut that puppy in half and see what the problem is on the cam. I kinda relate this to a eggshell getting crushed...

Otherwise what does the lifter look like?
 

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Butch
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Excellent suggestion Bret, You do that or you know someone who can do an analysis on it?
 

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Yeah... they do us favors time to time... considering that our machine shop business and the heat treater went back generations we have a good relationship. It's nice to be able to check the metallurgy of a failure to see what the root cause is... it doesn't help you get the motor fixed but lets you know WHY it happened or if QC down the line is at fault. The heat treating world is not easy and there aren't a LOT of people who are good at it.

Bret
 

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Butch
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Yeah... they do us favors time to time... considering that our machine shop business and the heat treater went back generations we have a good relationship. It's nice to be able to check the metallurgy of a failure to see what the root cause is... it doesn't help you get the motor fixed but lets you know WHY it happened or if QC down the line is at fault. The heat treating world is not easy and there aren't a LOT of people who are good at it.

Bret
I know a guy who did heat treating and he always claimed the cool down method/consistency is important (Some times he called it "quenching"), but he was old school and not sure if that applies now or not
 

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The largest problem is the lack of a definitive answer. This type of cam/lifter fail is abundant and can be seen/found all over the internet. Along with those is lots of different opinions on the cause(s). The most aggravating part of this is more than likely there is, in fact, different causes with the same ending result. This is the first time I've encountered such in a new engine and naturally would like to know "why".

It's an LS2 street engine, Comp Cam XER lobes, OEM LS7 lifters, 150 seat/460ish on the nose. Aftermarket oil pump, good pressure all around, high zinc/phosphorus oil with ZDDP additive to boot. I have my own theories but they are just that.
Send the cam out for testing, it'll usually turn up shallow heat treatment.
 
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