N52 Exhaust cam ledge/box issue

[80stech]

I'm starting to think a little more about trying to solve the lifter tick on my N52. By the way it's acting I am pretty sure it's a problem with loss of oiling due to the cam/ledge wear. There is some Chinesium replacement parts at a fraction of the price that look like they might even be an option if needed. If they are up there on quality with the metal valve covers then could be a good deal. Anyone have any experience either way with the cam ledge/box seal ring wear issue ??

[andrewwynn]

Looks like BMW has a new one piece recangring that alone might resolve the issue.

https://help.fcpeuro.com/hc/en-us/ar...wear-explained

The one n52 i worked on would get significant "lifter" (literally "follower") tick but resolved from enough constant drive eg. 30 minutes @ 65 following the TIS bulletin. Always came back when just short drives. (In my case just the lifters)

When rebuilding m62 we replaced the rectangring and the originals were measurably smaller with digital mic.

If you have other cars so you can down time the X, i think you can open it up and measure the parts and determine how bad the ledge v the rings are worn before deciding what parts to replace.

I wonder if anybody makes a "lifter" that's not as slow to adjust as the OE lifters that are famously noisy on the n52 motor.

Are you getting any vanos codes or just the noise?

It's not a terrible tear down to get the vanos gear off, if you have good measure tools to confirm the 3rd party vanos distributor are within spec, it feels like a worthy consideration. It's not electronic so i wouldn't put it in the same class of "mission critical" even though it technically is of course.

It sucks that you'd have to tear down, rebuild and set timing just to try the Teflon seal but if you can buy the distribution part where you can return that's the route I'd take (get the new seals and the distributor, if old ledges not too badly worn just use the seals, else install the China part with the new seals).

[80stech]

I have no codes and car is running fine, just trying to wrap my head around what I might be up against and have some options. I have only seen pictures but I don't really understand how the wear happens, the rings should be stationary in the ledge bore unless there is back and forth movement of the cam maybe when the vanos is operating ??

[andrewwynn]

I'm betting the ring gets pushed fore/aft from the oil going through it causing wear on the edge. It was five years ago i can't recall exactly how the parts overlap. Does the tapping get worse or better when the oil is thick/cold or hot/thin?

The vanos uses a helix gear set inside which could convert rotation to linear force like you're suggesting but i don't think it does that said, the rectangring may be what holds the cam in place fore/aft and just the weight of the cam would push against the rings from braking/accelerating.

A thought: the injectors can sound like lifter tick i was caught off guard be that but it's much more subtle like using steel brush on a symbol tshh vs tck. (lifter definitely louder)

[80stech]

Maybe the seal ring gets spun at times like when the oil is thick or even gets stuck to the cam if the car is sitting for a long time and causes the wear especially since the lock portion could have sharp ends. The seal rings can't be holding the cam in place or the teflon ones would never stand up.

[andrewwynn]

Originally Posted by 80stech

Maybe the seal ring gets spun at times like when the oil is thick or even gets stuck to the cam if the car is sitting for a long time and causes the wear especially since the lock portion could have sharp ends. The seal rings can't be holding the cam in place or the teflon ones would never stand up.

Good call on both points. I looked at a tear down video but not enough detail to see where the axial thrust is held.

On closer look, thrust looks like it's held in place from the inside between the two recangring seals.

https://youtu.be/Y8tUIiiza1A?si=z90fuA2TN0tWfPXy

From an e90 but i think n52 and very detailed video will give you good heads up on solving your noise. He replaced his lifters which four were soft on initial exam.

I think the recangring are always locked to the cam and spin in place and logically you're correct that the gap will be where it wants to cause wear.

On the video he replaced the intake can shell from boneyard.

With no vanos errors I'd bet lifters are your noise source.

If you copy this video and discover no cam ledge problem just replace the seals with Teflon and change the lifters which are stupid easy compared to most where you need to release the valve spring.

[80stech]

What I would really like is to get some feedback about the quality of the chinese cam and box, it seems that the used ones are competing with the price of the aftermarket ones which they really could charge double and still be a third of the cost of new OE so maybe the aftermarket new are fairly decent. If the new ones aren't good then I might buy a used set ahead of time when there is one available. If the chinese are good then I can order new anytime if I need it. I really can't afford the cost of a new OE cam and ledge.

[andrewwynn]

Ouch that's right: cam and casing would be a matched set when used!

Is the China set the shell/ledge and the camshaft? Or you use your cam inside the China shell?

Are they on eBay/Amazon etc where there might be some reviews post install?

Did you post a link i missed?

[80stech]

I just checked E-Bay, I think the new cam and ledge are sold separate and used can be either way. Normally I wouldn't even consider the cheap aftermarket parts but I have changed to the metal valve covers on both the N52 and my wifes X3 with the M54 and the quality is really impressive.

[andrewwynn]

I saw those metal VC and almost switched on my N55 when the vacuum reservoir failed.

The cam is a whole lot less critical than the crank i think you cold use an old cam in a new cam shell but I've not done before you should just end up with a little tighter tolerance around the "bearing shells" which should help with the oil pressure and lifter tick.