SL 450 timing question?
 

1980 SL 450 what is the timing spec? Sometimes blows black smoke, loads up any idea?

RE: SL 450 timing question?
 

0 degrees, or Top Dead Center with vacumme advance hose attached.

If this is a US model it should have a sticker in the engine compartment with this information on it. If you find such a stick then go with what it says.

After checking the timing you should have the emissions tested as it seems to be running too rich. The air/fuel ratio could be off but there is no way to get it right without a tailpipe sniffer.

Sam