Black sparkplugs

[Guest]

Hey guys,
As of late, seems that all six of my plugs are black and sooty, not really wet, just carboned over. I have leaned out the ZS's (all three), changed to a set of low resistance plug wires, running Sport Coil. Points are ok. Stock fuel pump. Timing is good (8 degrees BTDC, centrifugal advance). Any suggestions on getting these things to tan out. Seems they were nice and tan in the past. No smoke out of the exhausts, although they are nice and sooty as well. Perplexed.....

Bill

 

[Dave Russell]

Bill,
The first thing to verify is that the plugs are the correct heat range for your engine. If they are, things are still too rich.
D

 

[piman]

Hello Bill,
a couple of obvious points, air filter clear, choke coming off properly? The other point is what was the engine doing prior to removing the plugs?. You may want to do checks after different modes of running, i.e. idle, cruise and full throttle. Another check is the colour of the exhaust tail pipe, a car tuned fo economy will have a light grey colour although if for power then it will probably be black so this is not so useful.

Alec
PS. You might like to check your valve clearances also.

 

[Guest]

I switched my plug wires from "High Performance" 8mm wires to stock-style (NAPA) low resistance 7mm wires and now have nice tanish-white plug tips. Too much resistance with the Lucas Sport Coil? Go figure.

Bill

 

[Geo Hahn]

Glad you found the problem. I'm not sure what 'high performance' wires are made of. I always use the inexpensive copper stuff, reliable and connects solidly with the 'set-screw' dizzy cap in the TR3s & 4s. A universal 8 cylinder kit is enough to make about 4 sets for the 4-cylinder TRs. Lousy for radio reception but great for ignition.