M111 Spark Plug Gap ?

[shanksy]

Another quick question.....

Does anyone know the correct spark plug gap for the M111 engine in my '94 e220 coupe W124

Manual I have mentions only 'set to the correct gap' which is really helpful !

Cheers

 

[markjay]

That depends on the make and model of the plug. Different manufacturers quote different gaps...

 

[shanksy]

They were just the OEM Mercedes ones

 

[markjay]

They would still be either NGK or Bosch, with the model stamped on the metal bit at the base of the plug....

 

[grober]

0.8 mm usually come preset at manufacture

 

[markjay]

See for example this MB-branded NGK plugs:

 

[markjay]

0.8 mm usually come preset at manufacture

Yes, most models are quoted as 0.8mm, but some models are 'pre-set' i.e. you are not supposed to change the gap from how it was set at the factory. Also, multiple-electrode plugs should not have the gap set in principal. It's best to have the plug's part number to be sure...

 

[shanksy]

The ones I have are Bosch F8DC4 's

 

[markjay]

In this case....

 

[markjay]

The full list is here:

http://www.retrospeed.org/documentacion/bosch_spark_plug_guide_official.pdf

 

[shanksy]

Perfect, cheers mate

 

[grober]

Don't be tempted to run multi electrode plugs in the 111 engine they don't like 'em idle wise . Even later compressor versions of the engine which had multi electrode plugs fitted as standard by MB benefit from using the newer design NGK iridium fine single electrode plugs which were a subsequent upgrade SEE THIS THREAD http://www.mbclub.co.uk/forums/engi...k-rough-idle-detonations-exhaust-headers.html