New Spark Plugs

Bit the bullet at 33000mls & changed the plugs on my 1.6 today. Decided not to wait until 36000mls as off on another European trip soon.

A bit fiddly compared with what I have been used to in the past but reasonably straightforward.

Put plenty of white waterproof sealing grease in the tips of the coil packs where they meet the plug heads & also round their seals with the cylinder head to prevent ingress of damp which will cause corrosion where plug head meets coil pack & spoil the spark by reducing transfer of current. Needed a torque wrench that does low settings & just don't drop a coil pack retaining bolt as they can be b*****s to retrieve from under the manifold!

Although the illustration of the plugs I bought showed conventional plugs with a central electrode & one earth electrode, these plugs had 3 earth electrodes! Never seen that before in all my years of pulling wrenches.

Did some research & there seem to be two reasons for multi electrode plugs. 

Longevity: 
The spark will always take the line of least resistance so will eat away at one electrode until it's gap becomes bigger than the gap to one of the other electrodes. Then it will transfer it's allegiance to the next closest electrode thus maintaining an optimum gap over an extended period.

Cold Fouling: Extract from an NGK info sheet ( http://www.eurocarcare.net/user/downloads/pdf%20files/NGKsparkplugcat.pdf for any petrol heads!) 
To combat the ‘cold fouling’ effect that can occur in some engines using unleaded fuels specially arranged earth electrodes are sometimes used. These can force the spark to discharge across the insulator and thus burn away any built up carbon that could cause poor starting or misfires. It is not uncommon to find two, three or four earth electrode arrangements in new vehicles. 

Believe it or not I can actually feel a difference after changing the plugs. The old ones did look well worn. Definitely smoother so worth the effort.

I now have a car that feels better & I've also learnt more about plug technology.

Seems that you can teach an old dog new tricks!!!!!!!!!!!!!!

Also re-set my average mpg read out to find that after an over 400 mile round trip to visit the Morgan factory at Malvern the figure was 41mpg. 

Never got better than 37 on a similar run before.

That augurs well for our upcoming trip to the Austrian & Italian Alps.

After more time my everyday mpg has settled to 38mpg whereas I used to get 34 if I was lucky. So good news all round.