80 450SEL 116 Timing chain

[JRBrown]

Saw the earlier post on timing chains and hope you all don't mind my asking a question or two along the same lines. I own a 1980 450SEL, 129k miles. I've never changed the chain etc. I have been advised by two very conservative MB mechanics that the weakest link in the chain, tensioner, rails is the tensioner. I will know that it is going when I hear what is basicly chain slap for a few seconds at cold start up and then it goes away. That is suppose to be the chain tensioner, that is normally tensioned one direction hydrauliclly from the oil pressure, now only being tensioned with an operating engine.

Although MB has never officially endorsed the 100k swap out, there are enough horror stories and recommendations from the MBClubA and experienced techs and owners that prudence dictates that a FUD(fear of distruction, not my term but i like it)/PM based R&R is warranted. I've had three different recommendations from three other MB shops:

#1 swap out the chain and tensioner. (least expensive).
#2 Swap out the chain, tensioner and tensioner rail.
#3 swap out chain, tensioner and ALL of the rails (very expensive $2000+, very labor intensive since the front of the engine must be dismantled).

Okay, this is were I can't muster enough neurons to find the answer. What's the best answer? #2 seems to be the most prudent since swapping out the tensioner rail is a no brainer since the chain swap is happening at the same time and it doesn't require tearing the front apart.

I know this is like starting a discussion about oil change intervals, lots of opinions, but thoughts and advice are welcome. Any long term MB mechs want to tackle this one? Tackling this job is within my skills but I'm going to turn it over to the pros. Just not enough time.

S, J.R.
1986 280GE LWB
1980 450 SEL
1981 Volvo