Chain Replacements

[Andrew 06M3Cab]

Well, I just picked up my car after replacing the con rod bearing shells and all power steering components. My mechanic, who I have used for years and trust implicitly, told me my chains (timing chain and oil pump chain) need to be replaced. I can't hear it in the car yet, but he said he could hear it rattling when the car was cold and he turned the steering rack completely in either direction. There is no scoring of aluminium that he could see. What surprised me was that he said he couldn't remember exactly, but thought it was between 20-30 hours. He is always fair, only charged me 9 hours labour to do the connecting rods and whole power steering refresh. I had been planning on a complete cooling refresh this fall and i suppose it would make sense to do it at the same time. But the 20-30 hours seemed high. Perhaps because he said he usually ends up doing the VANOS at the same time. Anyone have thoughts?

[jet_dogg]

Tangentially, has anyone directly compared timing chain lengths with new and high mileage s54s?

I'm not sure if I buy the lifetime chain story, other models have had stretch over the miles.

[Tbonem3]

How many miles?

I've been in this S54 world for 12 years, and I can't really remember anyone having issues with chain stretch.

I just did a valve adjust on my 123k car, and for fun, pulled on the chain and I couldn't get even lift them off the sprocket at all. They also seem more robust than motorcycle chains that I'm used to.

For perspective, in motocross, you pull the chain off the back of the big (rear) sprocket and if you see light coming through(teeth to chain), you replace.

So did your mechanic pull the chain off the sprocket or measure the length of stretch?

If he's just going off of noise, there could be other culprits, other moving parts in the valvetrain that he may have heard (broken chain guide?)

[lemoose]

Hot take: sounds line a competent mechanic but possibly not proficient with the s54 specifically. Cant speak for your case specifically but the chains themselves arent known to fail on these motors- but plenty of parts that the chain interact with do.

[Andrew 06M3Cab]

How many miles?

I've been in this S54 world for 12 years, and I can't really remember anyone having issues with chain stretch.

I just did a valve adjust on my 123k car, and for fun, pulled on the chain and I couldn't get even lift them off the sprocket at all. They also seem more robust than motorcycle chains that I'm used to.

For perspective, in motocross, you pull the chain off the back of the big (rear) sprocket and if you see light coming through(teeth to chain), you replace.

So did your mechanic pull the chain off the sprocket or measure the length of stretch?

If he's just going off of noise, there could be other culprits, other moving parts in the valvetrain that he may have heard (broken chain guide?)

I'm at 215k km (132k miles). He said that he was just going off the noise at this point, which he said was faint. I specifically asked about the chain guide but he would have to get into it to determine. Like I said I plan on doing a complete cooling refresh, and VANOS later this year. So that would be the time to do it all. I was just curious about his off the cuff hours estimate.

He is quite knowledgable on the s54. He owns an M3, and there is usually at least one other in the lot when I take my car in. He said chain stretch is not common, but he has seen it, usually over 250k km (150k miles).

[terra]

IIrc, SliM3 did have some visible chain stretch which he showed on the old forum. But I haven’t heard of anyone having a problem due to chain failure.

[sapote]

For perspective, in motocross, you pull the chain off the back of the big (rear) sprocket and if you see light coming through(teeth to chain), you replace.

I don't think motorcycles use a chain tensioner, which takes most of the chain slash out in our car.

[sapote]

I was just curious about his off the cuff hours estimate.

This chain has no open-link, so to loop it around the crank sprocket, the timing cover might need to be removed. Then the vanos has to be re-timed again. The timing cover removal takes a long time.

If the tensioner has not bottomed out of range, then I would leave the chain alone.

[Darbshaw]

Tangentially, has anyone directly compared timing chain lengths with new and high mileage s54s?

I'm not sure if I buy the lifetime chain story, other models have had stretch over the miles.

I had to rebuild my engine around 160k miles or so and have little to no chain stretch compared to a brand new chain. It was so little that it could have been a testing error. Wish I had a picture but unfortunately I didn’t take one.


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[jet_dogg]

I had to rebuild my engine around 160k miles or so and have little to no chain stretch compared to a brand new chain. It was so little that it could have been a testing error. Wish I had a picture but unfortunately I didn’t take one.


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How did you compare the two, suspend them or lay on top of each other on a flat surface? A proper method would be a gauge of sorts I imagine.

I'm thinking they're cheap enough to do while I'm in there might as well.

[sapote]

The big problem with stretched chain is that the chain doesn't mesh well with the sprockets, and so sprocket teeth causing the chain to vibrate too much -- leading to a harmonic oscillation which can damage the guides.

[Cubieman]

One must pull the head to replace the chain on an S54 correct?
I thought I had read online about a shop that had come up with some method of replacing the timing chain without pulling the head and thus saving many hours of labor, maybe I'll come up with the link.

[jet_dogg]

I believe it was dr vanos who had said that, in that case not worth changing.

[George Hill]

To remove the lower timing chain cover you are supposed to pull the head.

[Andrew 06M3Cab]

Thanks for the input. Having to pull the head makes more sense of the hours estimate.