Distributor riding up

[landsea]

Hi all, I've been chasing a problem for a while now. My stock distributor on my 69 280sl left me stranded with no spark. After a lot of nonsense, I finally realized that the whole distributor had actually rose up and out of its groove. Bent the clamp!  I figured its old and worn so I got the 123 tune distributor to cover some bases along with a new clamp.  Ultimately it did the same thing in a short amount of time, I had removed the spring before installing so was feeling confident.  I have a bad feeling the seating groove has damage and is forcing these distributors up like a screw.  I can't find any info on this problem or a fix. Appreciate any help.  Ken

[rwmastel]

Ken,

Welcome to the Group!  Are you new to using the Search feature on our forums?  Keep trying different terms, you're bound to find something.
https://www.sl113.org/forums/index.php?topic=30783.0

Do you understand all the components below the distributor that drive it?  Perhaps there is too much slop/play beneath it (in the washer, or eventhe gear), and the timing gear slams upward?  Just a guess.  Search for timing gear washer or similar.  Probably search the Drivetrain forum as well as electrical forum.

Any idea of actually miles on this engine?

[landsea]

Thanks, I have found a bit of info today searching, "distributor drive gear".  I would not be surprised if this is the problem. Now to learn how to replace it.

[rwmastel]

A new gear is extremely expensive. Hopefully it is not worn.  There is a bushing or washer on top of the gear that wears out.  I believe JA17 shimmed mine years ago.

But, like I said above, I don't know if this is the problem so I look forward to hearing the thoughts of others.

[yves]

May be the 123 shaft is turned by 180 degrees…? If i am not wrong, the tab at the end is not symetrical…

[Runale]

Im not sure if relevant but do check if the damping spring is still there under the distributor dog of the assembly.  It does absorb some uneven movement of the timing gear.

[landsea]

Thanks all, 123 distributor is not 180 out, spring has been removed per 123. The clamp actually gets bent upwards until the rotor shaft dis engages. Probably going to make a stronger clamp,123 clamp is aluminum. otherwise running good, still a bit rough 1700-2300 rpms.  working on 123 tune settings.

[rwmastel]

May be the 123 shaft is turned by 180 degrees…? If i am not wrong, the tab at the end is not symetrical…

True, the slot at the top of the gear shaft is offset.  But remember, OP said the original distributor also pushed up, so swapping in a new 123 didn't help as it did the same.