If I'm reading this all right he's taking his current LS7 Lifters and measuring them to the new Johnson Lifters so he can figure out his Pushrods. .095" preload on the LS7 Lifters is the upper extreme of the proper threshold of .060"-.100", however if his target is the same for them Johnson Lifters with the above info that you both posted there's going to be problems. Way over spec.

Hey that's that advice on the Forums that some people come here for, back in the old days and all that sappy **** that apparently doesn't exist anymore.

However, we all clearly don't know what we are talking about since we don't have a shop of precision measuring equipment to measure everything outside of the Engine unassembled with precision accuracy and throw it all together when it's go time.

This is why it's comical to me at this point. Parts failure due to worn parts and exceeding the mechanical limits of those parts, but the hardness of the Camshaft is the sole problem here.

Upper end preload numbers on the Lifters combined with most likely wore out Valve Springs, ontop of wanting to install the new ones without actually measuring correctly for their proper spec.
Yup the failure is due to not knowing the actual **** needed to know and doing things RIGHT.

But we aren't 70 years old with all this high end experience so we don't know what we are talking about. Literally me right now...

 

The more you post, and OFF TOPIC, I might add, the farther behind you get. I never asked for advice. I asked for people WHO HAD PREMATURE WEAR ON CM CAMS. EVERY Cam manufacturer has had premature cam lobe wear to some degree, and AGAIN, I'm not saying it's CMs fault. So far, I've had damn few comments on topic. As for my way of comparing lifter preload, there's nothing wrong with that. I never said I'm not going to double check it when it's assembled. Sheesh, one guy even posted that I'm bored!! WTFF has THAT got to do with cam lobes???? I don't profess to know it all. There are guys on here smarter than me-And YOU. If you have nothing to contribute here, leave.

 

My whole post was literally on topic, addressing every damn thing you posted here.
The thing is, you just don't want to hear it.

You come in here talking about how forums are for community help and advice, there's some really awesome advice in this whole post yet you're stuck in your ways on your path and won't deviate. That's the polite way of saying your head is up your ***.

You came in here posting a tore up Camshaft, several of us said investigate the problem further it's not the Cam. Eventually we've collectively narrowed it down to possibly what it is as well as some errors in your methods (you REALLY don't like that one) and now we are here.

Can't take the criticism, don't make the posts. We are here giving advice but it's falling on deaf ears.

God forbid people chime in with something other than your prefferd conversation of Cam Lobes, in that case you're guilty yourself since you've talked about other stuff. Do as I say, not as I do eh?

Let us know the next time it breaks. We'll be here.

 

Hello,
Great you have your heads back. Pray tell me what are the guides made of? Iron or that funny yellow looking stuff?

 

Sir, this this thread is about Cam Motion Cams only, stated by the person posting it. You may be chastised.

 

[QUOTE=the_merv;20571012]Sir, this this thread is about Cam Motion Cams only, stated by the person posting it. You may be chastised.

Well, I understand your point, in my humble defense..........

The OP original problem and discussion started out with worn valve guides.

https://ls1tech.com/forums/generatio...after-fix.html

Which seems to be forgotten in the "What to blame" discussion.

I am attempting to bring the possible guide wear problem into the discussion about the cam wear, as that has been neglected in this current thread.


Below is my first of three in that above thread, the response to the above guide wear post.

Talking iron guides?
Hello,
This is the short reply,
So this my thinking, tell me if I am wrong. The chrome plating on the after market valves is too thin or soft so after the plating is worn off the stainless steel and cast iron guides gall and wear out out the guides. So the Manganese Bronze guides is necessary to prevent the galling between the stainless steel and iron guides. The OE valves must be a better quality so the chrome does not wear out.
So let me know if this correct or not.
The longer version is here
https://ls1tech.com/forums/generatio...-part-two.html

Hope that helps
__________________

So either I am guilty of bringing up irrelevant questions which should be and are ignored, or just maybe, the galling of the valves stems should be consitered in the problem of the cam wear. One would think that sticking valves would increase the opening pressure on the valve train...lifters and cam. In which the pitting would spread to the other lobes by the debris flying around.

In asking what type of guide now installed in the heads by Tony would be a clue of what a professional builder uses.

Yes, I am using Grinder's posts to get an answer about iron guides causing galling with stainless steel valve stems.

Thanks for not spanking me right off the bat!
Let me know what you think.

 

So improper lifter preload specs used and guide wear are two things the op didn’t mention. Hmm. Just the facts lol

 

Guides wear to a point the valvetrain becomes unstable thus causing wear on valvetrain parts. That's impossible!

 

I know 2 people with LS7's that dropped Valves and did the Piston Delete Mod while on the highway, fault was determined to be the Guides.

Damn, we forgot to keep it related to the topic..

Cam.

 

Merv here must have thought I was being serious.. I was being very serious right up to the point until I said "that's impossible"

 

Trust me I got the sarcasm haha.. Why I added mine.

Cam..

 

UPDATE: Will be sending the springs to Tony by the end of the business day Friday. Will also check hardness on the Rockwell tester the same day. Will post the results of hardness testing either later Friday, or Saturday. Unfortunately, Tony is around 2,500 miles away, so springs will take roughly 6 or 7 days to reach him. I'm certain he'll post the spring results as soon as he can. He's a busy guy....

 

Hardness results are in. First, we tested the 3 middle cam bearing journals as a baseline. All measured between 59 and 62RC. All the lobes we could check, except the bad one, were 56-58RC, which is fine. You'd think the lobes would be harder than the bearings, but they were not. That surprised me. Now for the bad one. It came in at 51RC, which, IMHO, is marginal, at best. How they all wouldn't be the same within 1 or 2 numbers, I have no idea. I'm certain they heat treat the entire cam in a furnace at once, so temps should be uniform. Perhaps uneven carburizing somehow?? Now for the biggest red flag of all. We tested all the base circles/heels that we could. All measured the same hardness as the lobes, in the mid 50s, EXCEPT the bad lobe. It came in at just over 30RC! This is about the same as pre-hardened steel!!! So, IMHO, that lobe is somewhat suspect. We tested, and re-tested that heel in at least 3 or 4 different places. We never saw over 32RC. That doesn't cut it. I suppose that lobe could've possibly work hardened to the 51RC, which may be why it was only 51RC. To those who doubt the results, go for it. I'm done with the thread. Most of the posts here could be posted in an off topic section. Some of you guys act like NOBODY ever got a bad cam. Nothing is perfect, you, or me included. These are my results, as tested in a QS9000 inspection department, by a qualified inspector. They are what they are. I have an engine to build. Later........

 

Oh, BTW-The new cam and the damaged old cam BOTH have the same distance from the bearing to the base circle/heel, which narrows down some of the PR length. It'll be interesting (to me) if my Trend 7.800"lg. PRs will be in the ballpark somewhere, which is why I checked the heels. Good starting point.....

 

No you're not homie, there's Valve Spring results to be posted.

We'll be here when you have future problems.

 

Great tech results Mike. I suspected you might have a soft lobe set there. This is the best TECH I’ve seen on LS1TECH in a looong time. I certainly don’t understand all the roasting and craziness going on here in this thread. You simply asked if anyone out there had any odd CM issues. Then the circus started…

 

Circus came to town when there was talk of Valve Springs that were good to 75k+ miles with .600 lift Cams, and how to gauge Pushrod length measuring the Cam ramp angle off the light refraction from the 3rd Ring of the Planet Saturn.

I'm not impressed by posting the Rockwell Hardness numbers of a Cam. I can literally do that where I work. Can take a whole Cam and test all 16 Lobes every 1/8" along them if I wanted to.

There's other things that have been proven to be the incorrect methods as well, us as the criticized community forum that are supposed to collectively offer advice and all that have chimed in, and been chastised for doing so. That's why it's entertaining. Not one of us is clearly going to change the mindset of 70yr old hard headed fool so we will sit back and watch when something else blows up because they "think" they know the method and don't want to pay attention to actual specs things need to be built to. Just the truth of what happened here. Truth hurts nowadays. Deal with it.

Not my money, not my car, not my problem. Carry on and blow the **** out of it, full send. Impress us.

 

I disagree. The ls7 has a .590 lift cam. Call it .600 if you will. Those engines go 100k+ on stock springs. Only about 10% have valve drop issues. I could easily see Mikes car going 75k miles on these springs. Really doesn’t matter if they turn out to be weak springs after Tony tests them…Mike drives this car SUPER easy. we all drive around on used, weak, valve springs. Heck…my wife has put over 300K on her last 4 Alimas. No problems with valvesprings on any of them… Know what I mean?
Regarding the pushrod measuring deal…if the heel of the new cam measures the same as the old cam, the math is super simple to figure for new cam regarding pushrods. Don’t worry…Mike is a trooper and WILL measure for new pushrods regardless…he’s simply using an old trick we use to get in the ballpark for pushrods. You guys jumped all over him about this..I was rolling…I guess it’s an old method that some of you guys haven’t used before.
Doesn’t really matter if your impressed about the Rockwell hardness testing or not. It’s legit and it’s actual TECH….very seldom on here do we see actual tech. Bravo Mike for testing this stuff, both cam hardness AND springs. That’s going WAAAAAAY farther than anyone here lately.
Mike never chastised anyone here. I don’t follow what your getting at. In fact…you did most of the chastising here. A couple others jumped in because it’s an Internet forum and that’s simply what humans do. They look smart behind a keyboard…ok.
FWIW, Mike is a recently retired tool and die guy who can use instruments with his eyes closed. I’ve talked with him one the phone a few times over the last couple years and he’s a really smart guy, WHOS STILL WRENCHING ON A C5 CORVETTE. You own a C5, so you can relate to this. It’s a chore to tear the front off of those engines. He’s still at it at 70. I tip my hat to him for that. He doesn’t have a lift either, so that’s bonus points for him right there. I’ve got a lift and I HATE digging in to my C5. I’m about to pull the rear cradle/torque tube out of my C5Z for the 3rd time…and I have a lift. Still sucks.
Mike knows and COMPLETELY understands specs things are supposed to be built to. He put an LS7 in that car along with Gen4 electronics and made the swap work flawlessly for the last several years. Mike would…AND SHOULD HAVE SPOKEN UP FIR HIMSELF…but he’s not that type of guy. He just laughs at all the antics here. Very thick skin, he has. Must be a 70 year old deal….anyhoo…carry on.

 

Does the heel have a lot of wear? Further below the surface, it'll start to read softer. So if there's significant enough wear, that could be the reason for a low value, not necessarily the other way around.

When you're referring to work hardening, are you talking about during the grinding process? Machining can increase hardness if done improperly, but in correct practice shouldn't. As far as the use goes, there's not enough heat and pressure to add any significant hardness (especially if the valvetrain was setup properly).

I don't recall if all the other responses in detail. But I believe intended messages regardless of the delivery are centered around a couple key points:

1. There are a ton of critical factors involved that can influence premature wear in the case of a valvetrain.
2. Failure of the part, doesn't necessarily mean the part itself is incorrectly designed or defective. Often people make the connection that way, but it can be incorrect more often than not, especially as you add factors of a system.

So it's not to dismiss the camshaft being defective, but rather be open to the idea the root cause may lie somewhere else. Yes bad cams happen. But so does bad valvetrain setup, bad oil, bad rollers, weak rocker arms, weak springs, etc. etc. etc. also.

Anyway I wish you well in your build. And I hope you do find your root cause whether it's the cam itself, the valvetrain setup, or another defective component causing the cam to go bad.

 

So, him not disclosing that his heads previously had valve guide issues and that he was running 95 thousandths lifter preload with johnson lifters were nonfactors and those of us asking about those details are bad people? LOL. Just trying to understand why asking details about the build and previous issues with the combination to help understand possible root causes makes us bad members here?

Odd that I was insulted for asking these questions like what was the lifter preload and how did you measure it? Those seem like legit questions to ask when there is a valve train failure no? When I ask those things I'm compared to a 5 year old because he doesn't want to be asked about details because it might be discovered that he had previous valve guide failure through no fault of his, but it did happen and might be discovered he was running lifter preload 50 thousandths beyond the upper spec limit of the lifters.

Instead of dismissing anyone who asked questions specific to the engine build and valve train setup and comparing them to 5 year olds he could have simply stated I did have a previous valve guide failure on my ls7 heads, but I don't believe that impacted the cam. Right or wrong that would be a better answer than attacking anyone who questioned him. When asked if lifter preload was checked and what preload was he running he could of simply stated how he checked and that when he switched from ls7 lifters to johnson lifters he had the lifters measured on precision equipment to make sure the same pushrod length would result in the same lifter preload for both lifters. This is probably satisfactory if you ignore the fact that ls7 lifters and johnson lifters require different preload. Instead he attacked anyone that questioned him.

The facts are he started multiple threads on the same topic which is a red flag in my opinion. Then would not answer questions about the build and attacked those that would question him. Some things were eventually answered and then showed some incorrect specs were used. The valve guide issue was never disclosed by the op and was only known because another member remembered that thread. Most of us know nothing about the op's engine combo so these types of questions seemed very reasonable to me, but we were attacked and compared to children for asking these types of questions. No one really said the op was at fault just asked questions about specifics of the build. After some of those facts did come out then that is when a few members started getting sarcastic. They got sarcastic because their questions were dismissed and they were compared to children how dare anyone ask the op any questions and when they did the OP immediately started making claims that his credentials were better than anyone else here how dare you question me...LOL.

Yep the rest of us caused this and the OP couldn't have done anything different to not send his multiple threads in an ugly direction...LOL