High Mile 560SEL: Lifter or Timing Chain Noise?
 

I've recently purchased a lovely black/black '89 560SEL with rather high miles (424k) under the pretense that it needed a timing chain. It has a constant clack that is present on cold starts, hot starts, and during operation. I maintain my belief that the noise is from the timing chain, however a friend mentioned that the issue could be a lifter.

Based on the assumption that the issue is timing chain related, I swapped on a used spare tensioner, to no avail. I assume that either A. the used tensioner was worn also, or B. my chain is so stretched that any normal amount of tension would be insufficient. I'm a bit conflicted with purchasing a new one when I inevitably do the chain, because it seems that the FEBI part is of very inferior quality and a new MB part darn near totals my car haha.

The link below is a video of the engine idling and I assure you there will be no problem hearing the noise.
https://youtu.be/pjyHeQFBVdo

Thanks all for any input!

Can you find an Iwis brand chain?

I've done the timing chain job on the m117s, oh, maybe a 100 times. That isn't going to be timing chain noise in your video. You hear timing chain noise at start up and it's a rattle, not a knock. I'd be willing to bet that's a flat(worn) cam lobe or a worn lifter or both if the noise is coming from the top end.
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That is 100% lifter noise, check your cam or lifter rockers for excessive wear

plastic cam oiler's? did you replace to aluminum?

I think that you're referring to the m119 engine. His is a 117.

I agree that this sounds like a cam was roasted by plugged cam oiler tube(s). And it's probably both cams. Any hydraulic m116 or m117 cam from 3.5 to 5.6 will fit to replace it (may have different timing but worst case is you get a little better performance as most 5.6s are de-tuned), just use either new rockers, or the rockers from the car the replacement cam came from in the same spots.

My m117 sounded just like this when I had roasted a few cam lobes on my passenger-side cam; the driver's side cam was in better shape but only slightly.

Note: Unless the chain was replaced, it would likely be a good idea, the excess stress from cam wear due to lack of lubrication likely stretched it further, so it should be done at the same time.

Thanks all for responses, I will "change gear" and focus on cams and lifters. Just prior to taking that video I had the valve cover off to inspect the chain and I will post some photos below. Being new to this sort of maintenance, I'm curious as to what constitutes major cam wear. I did notice some scoring but I wasn't sure how much would cause issue. I have attached some photos and I will note that the lobes felt largely smooth apart from the dark portion on the lobe I detailed. I suppose cam wear on an engine with well over 400k miles is relatively normal and not indicative of any major issues, or is this a sign of failed cam oilers?
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ba:
Based on the pics of the cam that you have posted, look for a leaking hydraulic compensator, aka, "lifter". If the left side cam lobes look as good as the right, then they are not the problem.

To find a single bad lifter, use a feeler gauge maybe .010 and try to find a "loose " fitting rocker arm might need thicker or thinner gauge, slip it between cam and rocker arm