Lunati reground the cam? I thought you bought a new one from Kip?

 

well the new replacement cam showed up today from Comp Cams. Im not really motivated enough to install it quite yet.

 

I did, but they still reground/repolished the cams as part of the warranty, so now I can at least sell them to recoup some of my $.

 

Yes they said it was within spec.

 

What exactly did they check?

I know Lunati had to do extensive testing to find what was wrong. it wasn't just a simple measurement.

 

He mentioned surface finish spec. I'm guessing the smoothness of the lobes. They repolished the cam no questions maybe there was a problem and trying to keep it quiet.

 

So apart from having a slight/minimal blower type whine, what damage to anything are these cams doing.
I have a Tick sns stg 3 & it has this whine

 

how long has your cam been doing this?

 

The company who grinded my noisy cams said it shouldn't cause an issue.
However, if you research Futral cams from 2006, they all had the same issue and were trashing lifters after 10-15k.

 

So they're all saying the surface finish of your used cams weren't up to par?

 

The cams whined since first start, it has nothing to do with mileage or them being used.

At the very least, the cams should be refinished free of charge and free of shipping (and they are being done so). I personally asked for a refund since my 2nd cam only had 25 miles on it when I pulled it right back out after the whining issue wasn't resolved. I did not get said refund though.

All of us in here taking our cams out have very low mileage on them. I would have taken mine right back out after first start, but I had to drive my car home from a friend's shop and I didn't want to tow it.

 

So you're sayings it's impossible that another factor could have caused the surface irregularities? Say its a "bad lobe design" as Kip mentioned earlier or even maybe the trays were old and worn and allowed the lifters to turn ever so slightly, causing the noises and even immediate wear so slight and undetectable to the naked eye that only "extensive testing" could identify.

If you swap the reground Lunati cam back in, and it is the exact same lobe profile, then that would be proof as it would eliminate more variables. But since it wasn't true A-B-A back to back testing, it leaves the door open to other possibilities still.

 

It's not a bad lobe design. I already mentioned Lunati found and admitted to the issue being on their end. If there wasn't an issue, they would have sent the cams right back.

My trays are not old and worn. My trays have 10k miles on them, same as the lifters.

I had two other cams before the Lunatis with no whine and one cam after the Lunatis with no whine with the same exact setup. I know it's the cam already.

I'm not arguing it with you anymore. I already resolved my issue by swapping to a different manufacturer. I only kept responding to help the others out.

Be skeptical all you want, I don't really care. The proof is already there. Choose to acknowledge that there is a problem or not, it won't make a damn difference to me.

 

I doubt the lifter trays are bad on all of our cars. My car has 34k the lifter trays are not bad. And my cam looked the same as it did new, when I pulled it out after 300 miles.

 

If by "not bad" you mean "not broken", there's a huge window in there for what is considered proper function and what isn't. The lifter trays are made of plastic. They're not some infinitely stiff material. New or not they're not going to be 100% effective at keeping the lifters from rotating in their bores somewhat if something is not right - if your cam has excessive end play or if the lobes have taper for example.

KCS has a point - there are an awful lot of variables to eliminate here. Blaming it all on the lobes when half the guys here won't bother to measure pushrod length, check camshaft endplay, measure bearing clearances, and invest money to have their valvetrain built properly is ignoring a large part, if not lion's share of the problem.

What were the bearing clearances with each cam installed? Were there any tight spots rotating it by hand? What was the endplay for each cam? Was lifter preload checked to compensate for potential differences in base circle diameter?

 

You only said that Lunati found an issue and it was too technical for you to understand and it was over your head, but you summize it's a "lobe surface problem". I'm not really trying to argue, but the "proof" that you claim is there is very muddy.

I'm just pointing out holes in some of the arguments made here before everyone grabs their pitchforks and torches and try to lynch Scooter Brothers or Billy Godbold. I've installed dozens, if not over a hundred of cams, both Comp and Cam Motion over the last 8 years or so. I have a Comp cam in my car. I've never seen or heard of this problem from any of the customers or shops that I built engines for, so I personally cannot offer any experience or explanation, but honestly my first thought is, "what did the installer do wrong?"

I can understand your frustration and I am not trying to add to it. It sucks to do all that and have problems, we've all been there. I machined and built an engine from scratch only to have my clutch slip when I put it on the dyno. If I wanted 400whp, I would have kept my LS1 in my car. I know that frustration, however, in that frustration, everyone wants someone or something to blame and will be looking for the first explanation that makes any bit of sense, without really carefully examining all of the variables or neglecting some altogether. I feel like there are still a lot of variables that could cause problems that have yet to be eliminated.

 

KCS, it was over my head. I do still have the email excerpt. David @ Lunati was very thorough in the investigation with his engineers.

I'm not trying to bust out the pitch forks, just trying to help people acknowledge there is an issue here, because before this thread blew up, we were all stuck with zero answers. I was really stuck, in that I had two cams that were noisy and over $800 into them, so I really spent a lot of time trying to get to the bottom of this.


Excerpt below from Lunati

Michael,

To further in the discussion on the phone we also checked the same lobes on another cam and it checked fine. In conclusion it looks like that UPR spike in amplitude on the 3 lobes could have been caused by an undressed wheel as it was not consistent in the rest of the lobes. This makes me curious to see the other cam too because I haven’t had this problem with these designs.

The cam had a slight amplitude spike in UPR (undulations per revolution) around the 150-200 range. The measured amplitude spike and frequency range was, in our experience, not in a range where we have observed audible noise issues and was within GM’s spec.

Keep in mind that a bad cam design can have zero audible noise if that spike is in a high frequency (not heard by a human ear). Vise versa you could have noise and it be a well-designed profile but if grind speed or wheel dress is wrong this can occur. Where it actually becomes a problem is when the spike is in the higher frequency; example 400 to 500 frequency range.

Kip made a good analogy to driving down the road; Let me make another. You hit one speed bump at 5mph it wasn’t that bad. Now you hit 10 of them right in row it’s a bit more noticeable. Increase speed (i.e. RPM) even more now. The speed bump is your UPR spike. The number of speed bumps is the frequency.

Hope this information helps. I know I have learned a few new things in the past week.

Best Regards,

 

Have you seen the videos? If each of us had something different causing the issue, the sound would not be 100% identical.

Also, if it was a lifter eating into a cam causing the whine, the whine would not occur right from first start. Furthermore, new cams from other manufacturers would whine as well, and they don't.

 

So you're saying that everyone in here has worn trays or turning lifters? But magically it was ok right before the cam swap? I don't mean to sound like a dick but it honestly sounds like you're a rep for one or both of the cam companies. Who really cares if its the lobe profile or a bad QC either way I wouldn't want one of those cams in my car. At every turn it looks like you're trying to lay blame on all these consumers. With one person there may be an issue but with multiple people and multiple cams there's no denying a company problem. No matter if its lobe design or surface finish the fact still remains that there is an issue that needs to be corrected and as of now its hard to even get comp to recognize there's an issue.

I'll try to take a crack at this but again this is pure speculation as I dont know what lunati said. I'm graduating this semester with a Mechanical Engineering degree and have taken a few classes on vibrations and harmonics so lets see if this makes sense. During grinding of the cams the tooling can leave very small ridges or tooling cuts on the lobes almost like the edge of a file would be. The ridges or tooling marks cause tiny changes in the velocity and harmonics of the roller on the lifter as it rides over the tiny "dips" on the cam. The higher springs rates, fast jerk and ramp rates of the cam profile exacerbate these conditions. Imagine taking that shop file and running a metal rod up and down it. The whine that is produced is a much more exaggerated condition of what is happening but the principle should be the same. If I missed something maybe one of the cam grinders would chime in but thats how I see the problem from an engineering standpoint lol

With that all said I'm happy to see people getting their cams fixed. My buddy has a NOS EPS comp cam going in his 6.0 this weekend so we'll see how she sounds.

 

Here may as well have a post linking all of them.

The sound is 100% identical, even between different makes of vehicles! We have PLENTY of circumstantial evidence as well as evidence directly from Lunati and Kip @ cam motion to definitively determine it is the cams causing the problem!

My first Lunati:

My 2nd Lunati:

Col45's Comp

00_MMM_Z28 Comp

C5 guy's comp

Joshua022 comp

Dodge Durango Hemi - Comp (not even an LSX car)

Different Hemi - comp (not even an LSX car)