Timing Chain

[SonnyA85]

Yes I know it has a tensioner to tighten it up should it become a little slack. However what is the general consensus on when they should be replaced?

We know they are rock solid that's a given. But nothing is built to last forever especially when subjected to wear and tear, heat, etc.

I think 20 years is long enough on the original and a worthwhile change nowadays. Am I right that the car has 2 chains as well an upper and lower.

I think I'll get mine done next year.

 

[Mr Tidy]

I don't know for sure, but it might help to know what engine your car has.

My MC needed a new tensioner at 78K miles because the original was sticking and leaking.

 

[PDJ]

On the S54 engine there are 2 chains

One is the timming chain this is a duplex chain and the other is the oil pump drive chain this is a simplex chain

As shown on Real OEM https://www.realoem.com/bmw/enUS/partgrp?id=BT92-EUR-05-2006-E85-BMW-Z4_M32&mg=11

 

[PDJ]

Here is the old timming chain tensioner follower from my engine

 

[mmm-five]

As far as I understand it, the timing chain shouldn't need changing before the engine gives up the ghost.

The tensioner/guides however can be inspected and replaced as needed - or on a regular basis, say 60-80k miles?

 

[grannyknot]

It is not just the chain that needs replacing but the guides.
To save $ you can get away without replacing #1, #2 will need it, #3 will be worn through or close to it, #4 you don't have to replace as there will be very little wear.
Replacing the tensioner for the main chain and the oil chain is a good idea too.

 

[SonnyA85]

I have a pre face lift 3 litre. I believe it's an M54 engine and circa 230bhp.

It is not just the chain that needs replacing but the guides.
To save $ you can get away without replacing #1, #2 will need it, #3 will be worn through or close to it, #4 you don't have to replace as there will be very little wear.
Replacing the tensioner for the main chain and the oil chain is a good idea too.
Screenshot 2022-07-20 at 16-23-00 RealOEM.com - Online BMW Parts Catalog.png

Okay cool I'll have a look at realoem and get the correct part numbers for my car and speak with my mechanic and see what he says

 

[grannyknot]

I have a pre face lift 3 litre. I believe it's an M54 engine and circa 230bhp.

Seems like 4 guys with S54 engines replied to you so I just assumed, the diagram I posted wont help you.
Since you're going to do the work anyway maybe remove the front timing cover and have a look at the condition of guides before ordering, you will be able to see pretty clearly the tracks the chains make.