Timing question

[Joern]

I am planning on buying a timing light/gun to check the timing on the car as it runs a little rough.
Now, the timing lights for sale like this one...

DRAPER 52616 XENON STROBE IGNITION TIMING LIGHT | eBay

...doesn't appear to have a way to set the strobe light like show in this video (at around 15 minutes 30 second)

Wheeler Dealers - S01E10 - Mercedes-Benz W123 230E by Ultra86 - Car Videos on StreetFire

So, I am a little confused...

What tool do I need to set the timing like in the video?

And yes, I have a w123 230e too.

 

[Joern]

OK so the mystery is solved... Some lights are adjustable, others are not. So for my w123 it appears I need one that can be adjusted to BTDC.

 

[grober]

Usually there are degree marks on the pulley or associated damper corresponding to say 5 10 15 degrees before top dead centre [ BTDC] WITH EDS TIMING LIGHT you use the TDC top dead centre mark and adjust the timing light. BUT with your non adjustable light you can simply put a mark on the crank pulley that corresponds to say 13 degrees BTDC ie 13 degrees out of 360 before the TDC mark.
You are then timing to the 13 BTDC mark and not the TDC mark he is using.

ps Make sure you disconnect the vacuum advance pipe from the distributor before doing this

pps typing correction fluid such as Tipp-ex works well or any white paint apply with a thin sliver of wood .
Likely timing "Static" 13° BTDC @ 850rpm [ AT IDLE ]
Dynamic 32° BTDC @ 4500rpm vacuum removed, 40-44° BTDC @ 4500rpm vacuum attached.

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[Joern]

I didn't quite understand all of the above…

Anyway, things sometimes take time….I have now finally purchased a timing light which I can set advance degrees on.
So tonight I tried it out.

So… am I understanding it correctly… I set the advance on the strobe gun to 13 degrees?

I tried this at idle.
Firstly the strobe gun 'strobed' erratically… The engine was cold mind…?
But suppose that shouldn't really happen?

Is there something else than 'timing' that could be the issue here?

It did starts strobing regularly eventually though…

 

[grober]

Usually these timing lights have an inductive pickup that clamps to the no 1 cylinder plug lead to trigger it. Any irratic strobing is due to this not always picking up the HT on the lead. If you mean the strobe light was moving about this would mean the timing was varying slightly. This can be caused by the revs varying as the engine warms up or wear in the distributer shaft altering the points gap if its a points type distributor or sticky advance and retard weights. If it settles down I don't think you have much to worry about. The timing is set to a specific set of values at a certain rpm/ with the vacuum advance disconnected/connected.

 

[Joern]

Thanks for this!
How do I disconnect the vacuum advance…?
So basically the guy in the video is not doing it right? Or they just do not mention that particular bit?

 

[Joern]

addition

Just a wee addition to this post in case someone reads it in the future.
For any of the w123 230e models, the vacuum advance should apparently NOT be removed. That is according to a manual I found.