I know I have posted about this before so I apologize I am just desperate to find an answer as it is driving me crazy. Does anyone else have this particular pecking noise on their cammed C6? I don’t know where to go from here. This is a newly installed stage 2 cam with supporting valve train. CHE trunnions and initially new LS7 lifters. The noise was there immediately after the install. I thought maybe I had a bad lifter, so I had the lifters changed to Morel 7717’s. Cam lobes inspected at the time with no damage. Pushrod length was measured and is correct. All of the rockers have been inspected as well. I have ruled out everything from an exhaust leak, loose spark plug, lifters, rockers, and bad cam lobe. So what else could this be?? The only other thing I could think of is that maybe it is a valve guide is slightly out of tolerance and is causing a valve to seat improperly. Other than being noisy, the car runs excellent and I have not noticed any smoke from the exhaust. What do you guys think? Send it or keep digging?

https://youtu.be/IYu3jSes1Yk

 

Send it!You have checked about everything possible.When and if anything happens.then you can worry about it.I realize your concern but sometimes you just gotta go with it!

 

yeah, that’s kind of where I’m at with it. I’ve been driving it every day and just turning up the stereo. I’ve thrown a lot of money at it with no change, so really the next step if I were going to do anything is probably replace the head but that’s a gamble of course. I think I’m going to keep driving it and as long is it runs fine in the sound doesn’t get worse I’ll hold off on replacing anything else.

 

 

Watched the video .... I don't really hear any clattering sound.

Maybe if your exhaust system was not so loud, I would hear it.

 

I’ll make another video later with the exhaust on quiet mode and you’ll better able to hear it much better. Didn’t think of that

 

I think your car sounds perfectly normal for cammed with headers. The headers magnify the valve train noise and the sounds are being reflected around the engine bay. Can easily make you lose your mind thinking something is wrong when there is not.

Something you could try (but it would take a little bit of work and a little cash), is to take the headers out and then wrap them in some header wrap. I bet you would not hear what your are hearing anymore as header wrap significantly dampens the header sounds.

I removed the titanium header wrap I had on my Kooks when I recently replaced my lifters (I had actual bad, likely counterfeit lifters). In the process, I found that the the wrap on my headers was deteriorating, so took all of that off and have been running just bare headers. The lifter noise from the headers and the reflected sounds from the headers are much louder now. I hear the sound much more now especially if my car is near a wall or thick foliage cover on the side of the road.

 

I hope you’re right buddy!
The headers definitely amplify valve train noises, I’ve had long tubes on all four LS cars Ive owned and they all four had much louder motors with headers. The sewing machine noise on this car is very noticeable especially when near a wall or guard rail and that is expected. It’s worse, im sure, because my headers aren’t coated nor wrapped. Im okay with that I know that’s just an inherent LS sound but the noise im concerned about is a very isolated pecking/tapping noise only on the driver side. The videos don’t reveal it as much as in person and is only on one side. It stands out pretty bad between 1500-3000 rpm’s. This could be a normal noise for some cars but I’ve not heard one in person yet that sounded similar. I guess where the car left me stranded recently while out of town has me paranoid of something happening again. I’ve been driving it everyday and just turning the stereo up a bit louder.I hadn’t considered pulling the headers off and wrapping them but I think I’ll do that one day soon. If nothing else it will quiten down the sewing machine chatter a bit. If it helps with the other noise it will be a win/win.

 

Same issue here ever since I did this BTR stage 2, I dunno if its a noisy lifter or what, (all brand new caddy lifters). Sounds like a damn exhaust leak and it drives me insane but everything checks out. I've just learned to live with it until I find the time to go back into it and redo my lifter setup. Curious has anyone gone to a solid roller setup on a street car for this issue? Anyway I feel your pain OP

 

I don't remember if you mentioned this or not but are you running single or dual valve springs?

Duals will have more valve train noise.

 

Yea they are duals. And I know the duels make a lot more noise than singles, but mainly just the springy sewing machine noise. This noise I’m concerned about is a very isolated peck only in one spot of the motor.

 

yea man it sucks. Does yours sound like this?

 

I will try to remember to get a video of mine.... Cammed through STOCK manifolds. Pretty damn quite under there.

 

Not so bad sound for me. What was the oil temperature for video take ? What is the oil in ? My LS7 is quiter with some ester 5w40. Motul 300V here in France but i would have take Redline in USA (RL price is horrible here).

 

The oil temperature was probably 205 or 210 in the video. It’s fresh AC Delco 5W-30 oil. I’ve tried a couple of different oils and the sound is the same. I found a brand new stock head for sale for a good deal so I think I’m going to try changing it out and see if that helps.

 

Why not send the heads to be worked is some good shop. AHP, WCCH, Katech,...?

 

yeah, that’s an option too. I don’t know if I really want to go through the whole process of having both heads pulled and sent off and then having to re-tune and all of that but that’s certainly an option. I have not been able to drive the car for the past year cause it’s been in the shop so it sucks having to go through this already but I just want it to be right. I found a brand new head for a really good deal and could have it swapped out pretty quickly.

 

I got mine from AHP to Paris in 3 weeks. No CNC flowing work either milling asked for however.

 

If you have any questions feel free to shoot us an email HP@americanheritageperformance.com
Always glad to answer any questions

https://americanheritageperformance.com/

 

Walk in the park, and either you don't have enough preload on the tappets via the push rods, or you need to pull the tappets to install limiters on them, since the problem is the tappets are not being pumped up high enough to keep up with the cam lobs.

As for new lifters, until you do them bleed correctly, going to be a rattling mess as well.

Standard lifter, and note that you have a void area under the check ball/piston in the body that no amount of oil in the side body channel is going to get oil down to that lower section, until the pistons has been pumped a few times to allow the air to release out of the lower section around the piston and fill with oil to begin with.


Also, on the up stroke of the tappet, the top cap lower plate does block off the push rod passage so the tappet can stay pumped up as its being forced up, but if not enough preload, or lower spring not strong enough, then your piston is going to be drive back down to allow valve train lash above.

The last one is check the bottom of the push rod cap, since it will have a U grove milled into it, to allow some of the oil to get past the push cap. Depending on the application if the tappets as not staying pumped up enough with high radical cams during idle, you have have to lessen the depth of U groove bleed by as well.

Really, what you are looking for is Johnson GM slow leak down, axle oiling lifters with limiters. The pistons will be tighter to the OD of the body to slow down the amount of fluid that can get past the piston body back to the top, the piston springs are a bit stronger, the U groove in the bottom of the push rod cap will be reduced, will help to oil the rollers better, and with limters in place, piston only has half the room for over all travel so you don't have to add longer push rods to get more preload on the lifters..

https://www.tickperformance.com/john...-part-2126lsr/,
And since they are tied together, don't need to run the plastic trays to keep the lifters from rotating and taking out the cam lobs.

Here is the travel limiters for the lifters as well.
https://larrysmcymachineinc.square.s...rue&cst=custom