Four Electrode plugs

[kiwi_bloke_nz]

Hi guys,

Was changing out the plugs on my M111 yesterday and found it had 4 electrode bosch plugs in it. They were quite sooty.

So decided to put plain old single electrode NGK plugs in. I have to admit they have been sitting the garage for a couple of years and had a few KM put on them - but the car runs alot better. Also took one back out and it was burning clean - very clean compared to the + 4 plugs...

Whats the general consensus on +4 plugs ?

[Matt L]

I've never used them. I have had vehicles that hated platinum-tipped plugs, but ran fine with standard copper.

[rodgiddens]

I've used both +2 & +4 Bosch plugs and haven't noticed any significant difference. I primarily use the because the center electrode doesn't wear away increasing the plug gap.