the clip has jumped off the chain

[Peter]

On my 4 years ago fully restored engine (280SL-1969) with 10,000 miles,
the clip has jumped off the chain link. (see picture).

1) Has this ever happened to anyone?
2) What could causing this to happen after 4 years and 10,000 miles (and not much sooner)?

Thanks for help, Peter

[Cees Klumper]

One of the key things is that the clip that secures this connecting link has to be fitted against the (clockwise) direction of travel, meaning it will naturally be 'kept in place' by the movement of the sprocket. Assuming that was indeed done, the only thing I can think of is that it wasn't seated properly when fitted - not 'clicked' into place tightly as it where. The other possibility is a manufacturing defect, that the clip was just too loose from the start.

(Last possibility that comes to my mind, but remote, is that the engine backfired/somehow 'shuddered', which unseated the clip.)

[Pawel66]

Was this chain connected by:

1. One clip?
2. Two clips?
3. Pressed?

Scary...

[JohnnyC]

Did you find the Clip?

Cheers and God Bless,
John

[Peter]

I will go down into the engine to find the clip and also hopefully the reason.

Apparently this is the first time this has happened to a club member's pagoda.

[stickandrudderman]

In the 42 years I've been working on these cars I've never seen a chain shed a clip. The closest I've come is on a M100 engine where the clip was worn 90% of the way through as a result of fouling something along its route. The owner refused to allow me to strip the engine to find the cause; rather he told me to fit a new clip and he sold the car. 

[Benz Dr.]

Master link  should point towards the back of the engine.

 I've seen a couple of chain links in the bottom of oil pans while doing rebuilds and I'm sure this was from being dropped into the chain case. None of them looked damaged but I can imagine that part could land in between the chain and crank gear.

[Peter]

Master link  should point towards the back of the engine.

If I understand "master link" correctly, it was done correctly? See the photo.

[ja17]

Yep, master link should be on the backside of the cam sprocket and the round end should be first in the direction of travel. Most new timing chains are using the two "c" clips instead of the one double clip.