Question on M117/350SL timing

[Graham]

I have never adjusted the timing on my 350SL before, so bear with me!

I have been told that the car will run best if the timing is set to about 30 deg BTDC at 3000rpm.

So, I found the markings on the dampener/balancer (?). They are hard to read. Someone had put some red paint to the right of (clockwise from) the 0 deg mark at about 10 deg - assume this is 10 deg BTDC. I then made a white mark at the 30 deg mark, further to the right.

I first rotated the distributor CCW a bit and attached the Sears timing light to #1 cyl wire. Disconnected and plugged vacuum advance tube, then fired up the engine. I could see the white mark stationery well to the right of the pointer.

I tried increasing rpm from idle to 3000+ rpm - the white mark stays in the same place. I expected the centrifugal advance to cause it to move?

I reconnected the vac tube and found that speed now caused the mark to move, but no better than about 15 BTDC at 3000 rpm wit distributor at max position in slot. So it would seem mechanical advance does not work? Car actually is running well with this new setting!

Am I doing this right?

If centrifugal advance is not working , is there a fix?

[Graham]

Previous message updated and corrected.

[Tomguy]

easy way to check if it is: Try rotating the rotor clockwise. It should move clockwise with resistance and then, upon releasing, spring back to the original position.

if it's stiff to move (or doesn't move) you may need to clean the mechanism. It can easily be done by removing the distributor and disassembling the top plate (on which the ignition points ride), then removing the "Circlip" from inside the distributor shaft (where the rotor sits on top of it). The top assembly will come out then, allowing you to clean >35 years worth of crummy old grease out.