Ignition Timing Plug

[flyingtech55]

Hi all

Can any of you tell me the correct setting for the rotary plug mounted on the front nearside inner wing of my 1992 190E 2.0L manual. It has only S and N positions. It got accidentally pulled off and as I had never had cause to alter it I don't know the correct position for it. The book implies that normal petrol requires the N setting and Premium petrol requires the S setting but is their normal and Premium petrol the same as the current stuff in view of the fact that the book was written a few years ago now. I use ordinary unleaded petrol.

Thanks in advance.

Gliderman

 

[flagstaff]

'N' for ordinary unleaded. i think you can use the 'S' for gas above 97RON (may be wrong though)

 

[television]

Flagstaff is right, it only alters the timing a touch, never found any difference. if it pinks on S, go back to N.

Malcolm

 

[tom7035]

Regular grade unleaded fuel - 91 to 94RON, premium is considered to be 95RON and above. (With cat., without cat. it's even lower).

 

[flyingtech55]

Hi chaps

Thanks for replies and sorry for delay in acknowledging same. After further research (I asked my Merc tech friend ) he said you normally run the cars in this country with the plug in the 'S' position as our normal unleaded petrol is considered 'Premium'. Position 'N' is used in countries where the quality of the petrol is both poorer and variable. This safeguards the engine as pinking can of course be very destructive.

I've tried both positions and there doesn't seem to be much difference but I think that the engine produces a bit more torque in the 'S' position and that's where I've left it.

Thanks again for your help

Tim