w108,107 Parts Hoarder
Date registered: Jun 2010
Vehicle: slc5.0cab 280sl5sp 280se4.5 500sl92 GONE:280sl79 4xW114/5 3x450sl72-3 280slc4sp81 280s69 73,81SLCs
Location: Philadelphia Area
Mentioned: 27 Post(s)
Quoted: 1573 Post(s)
Assuming it is identical to the 1972-73 450sl, you gap the points to 0.014 I believe which is about the thickness of:
- a playing card
- a business card
- a matchbook cover
Or get a set of gauges from your auto parts store.
More importantly, you are looking for somewhere between 20 and 30 degrees of "dwell", to measure you need a dwell meter. (This is one reason lots of folks switch to pertronix and love it. Lots of info on this in the r107 forum, EGv107.)
Since the points rider generally wears down and dwell (period the points are closed and current flows through them, low voltage current due to the use of transistorized ignition, also making the dwell/recharging period not as sensitive) increases as the rider wears down, I believe it's good to have the dwell on the short/small side.
Once you've set the dwell, then you go back and set the timing.
I realized that the AC in a 1973 450sl turns off the vacuum retard. So have the AC turned off when setting the timing. On my 1973 the vacuum is supposed to provide 10 degrees of retard putting it at 5 atdc at 750 (idle) rpm. 5 btdc without vacuum.
My dream car is a classic sporty five speed (stick+overdrive) convertible that seats five. If, you want 70's-80's Mercedes tuner wheels, let me know.