Sparkplug colours

Post by **RogerRust** » Mon Apr 06, 2009 7:58 am

I'm a great believer in making a close study of spark plugs to gain an indication of the engines state of tune and condition.

The plugs from the MG have a nice pale brown centre insulator and are not at all oily. However the end of the threads are a bit black.

Do you think it's running a bit rich or does it just need a good summer run out to blow away the cobwebs?

<br>

<br>

Post by **millerman** » Mon Apr 06, 2009 10:44 am

Is this link of use?

http://www.dansmc.com/Spark_Plugs/Spark ... talog.html

Post by **d_harris** » Mon Apr 06, 2009 11:04 am

Really useful link there Millerman. Thanks

Post by **dalebrignall** » Mon Apr 06, 2009 2:51 pm

mine are like that id think they are ok for unleaded fuel.they reconed when you had 4 star petrol the end of the exhaust used to go grey after a blast,but not any more with unleaded fuel

Post by **bmcecosse** » Mon Apr 06, 2009 10:12 pm

I would say it's 'just right'! Now you should do a full throttle run up a long hill, and near the top switch off and drift to a halt. Whip the plugs out - and see what colour they are under these conditions.