One black sooty spark plug

[John Tinks]

Hi

I have a standard 2.0L Pinto in a MK Indy kit car and I am getting one black dry sooty spark plug always number 3, running on a weber 32/36. I have tried

Swapping plugs

Swapping leads

Distributor round 180 deg.

removed PCV valve

Had block re-bored, skimmed, new pistons and rings, head skimmed, new valve guides, unleaded inserts, new valve oil seals

only using E5 petrol

Still No. 3 black and sooty mis-firing all the time

Any help appreciated ............ getting frustrated

John

[DaveT70]

Check valve clearances

Check compression on number three

Check dizzy cap and rotor arm

If you're running E5 set ignition timing to standard 4 star (original), not retarded for unleaded

[John Tinks]

1 hour ago, DaveT70 said:

Check valve clearances

Check compression on number three

Check dizzy cap and rotor arm

If you're running E5 set ignition timing to standard 4 star (original), not retarded for unleaded

Thanks DaveT70

Checked valve clearances and compression both ok, Cap and rotor arm look okay but will swap out and advance the timing