[BozoBlaster]

I've started to hear a knocking sound coming from the engine of my 335. Stethoscope probed around the entire engine top to bottom, front to back, and it sounds to be coming from the top end in the back around cylinder 5 or 6. I've checked the oil filter and no copper glitter so I would like to rule out rod knock, I feel like rod knock would sound different than the knock sound in this video.
[u2b ]https://youtu.be/4rVIwGM04RM?si=i8C3_n0UdV-7zeWP
[/u2b]
Removed the cams to inspect lifters, rocker arms, cam lobes and bearing ledges. Just over 107k miles on this engine so there is typical wear on the ledges, cams and rockers. About four of the lifters squish in maybe 1 or 2mm, the rest are very stiff, could this be what is causing the sound from the video above? I'm going to be replacing the rod bearings regardless because I'm going to be replacing the oil pan gasket during my upcoming single turbo conversion, and I also plan on replacing all of the lifters, would appreciate any input on if anyone would think this would fix the knocking. I have video on the condition of cams and lifters if that helps add more context

[Mustafa.e92]

could be lifters swap out the bad ones or all if in budget. Make sure plugs are tight and teflon seals on injectors are sealing. Does not sound like it’s a bottom end issue to me

[BozoBlaster]

I want to replace them all but I might have to settle for just replacing the bad lifters for now since an injector seal kit and seal compression tool is a lot as well. Around 500$ for 24 lifters, 22$ each for the febi bilstein, 92$ for the injector seal kit, and 95$ for the injector seal tool all at ECS tuning. I can find ebay lifters but I don't want to trust those if I'm planning on putting out some serious power after my single turbo conversion. Good to have another opinion though, thanks for the input. I'm learning about these engines as I go and its great to have this forum at our disposal.

[Mustafa.e92]

Join n54 tech and other Facebook forums. These forums is dead compared to those. You will get way more input

[BozoBlaster]

Right on, thanks, that's good to know. I won't have everything buttoned back up until I'm completely done with the build but I will update this thread when its all finished to see if that was truly the issue.

[BozoBlaster]

I also forgot to add to the initial post that I have plugged the headports and have gone external with the pcv system. But I'm assuming that shouldn't have anything to do with the knocking other than maybe exasperating the problem parts. Just a bit of extra context.

[TheMidnightNarwhal]

Doesn't sound like rod knock to me either.

[BozoBlaster]

Got new lifters to replace the bad ones, waiting for my valve cover screws, I had ordered titanium screws since the steel ones provided with the VTT valve cover had two screw heads snap with being torqued to just 8nm, and of course when I got the new ones a week ago vargas sent me the screws for the n55/b58 valve cover not my n54 so its being held up by their slow/terrible customer service.

[Kayden Biwer]

I’m having the same exact thing issue as you are having. My motor has 97k on it and it makes the identical ticking your engine is making. I also believe it is the lifters so I’ll be watching for an update on if that solves your problem.

[BozoBlaster]

I've got the car all torn apart at the moment for the ST conversion so it will be a few weeks at least before it's all back together and running, but its the only thing that makes sense on what is happening. I have a video I can post on YT of my squishy lifters if that helps and I will update as soon as the car starts.

[apexxx6789]

Torque down spark plugs to spec. Had the same issue.

https://youtube.com/shorts/vhzYnnu31PQ?si=3mGK_vpu60bCaKR7

[BozoBlaster]

Could a slightly loose spark plug really make that sound? I did change those like maybe a year ago, and I'm sure I just tightened them down to a reasonable tightness, I'll give them a factory spec torque and see if everything together solves the issue.