NGK Spark plugs

My car is a 5000s carbed, but the idea is the same. I think I have been running the 8, the 9 is a hotter version, probably what I should put next in mine. So yes, I'd run the 9.

 

With NGK spark plugs the higher the number the COLDER the plug is.

Generally speaking if you drive your car in mixed urban conditions where long higher rpm runs are not the norm then you will want to run a hotter plug. For track driving you would run a colder plug. It is important to note that plug temperature has nothing to do with engine temperature which is a common misconception. It is all about how clean you keep your plugs by ensuring they are operating at a correct temperature for the type of driving you do.

Both my Dino and 308 get driven mainly at medium engine speeds (although I'm not shy of a good run here and there) and have benefitted massively from hotter spark plugs. The engines are crisper and the plugs don't foul. There is no reason a Countach would be any different.

 

They are not suited for the car.. I have tested several plugs and the NGK never worked well in my car. Mine is a dd, so that might make a difference although I doubt it. I suspect that they run too cold and that was the issue. Oddly I ended up finally sticking with cheap Champion plugs and my car was never happier. $3.50 a piece and don’t foul up which was the problem I had especially with NGK.

 

What exactly was the problem you had with the NGK in your DD? I am running them in my DD already 2000Km and I am happy with them.

 

When I went to hotter plugs I also changed from Iridium NGK's to conventional copper core ones. I cannot comment whether it was the change in heat range that made the most difference but I can say that the much less expensive copper core plugs gave up nothing to the much more expensive Iridium ones.

I have been told (by someone MUCH more knowledgeable than me on spark plugs) that the NGK Iridium plugs run one number colder than the equivalent copper plug so this may also play into the considerations. To further complicate things NGK offers both a resistor and non resistor plug to suppress noise that can affect radio reception. This is indicated by an 'R' in the numbering of the plugs. Resistor plugs loose a little bit of spark energy so for the best and strongest spark I run non resistor plugs.

At present the plug I use in the 308 and Dino is a NGK BP5ES. It is one heat rating hotter than stock and repeated plug checks show no fouling and a perfect light tan colour. I also optimized my carburation by placing O2 sensors in the exhaust and tuning based on lambda values so I am certain my car is jetted perfect for the fuels and altitude I drive at.

 

The problem I had was the NGK plugs simply fouled up easily. 95% of the time they were fine, but throw in an odd variable and they would foul when given the chance. I had a weak battery and after a cold night, since it needed some extra cranking they fouled and then no start. This was on the Countach Rally so we changed plugs in the parking lot . Easy to do but always at the worst time. The cheaper plugs have proven less finicky.

 

Ken, would you mind sharing, please, the model number of the spark plug you are using in your DD? Thanks!

 

RA8HC. Champion.George Evans recommend in my qv fi. Works great

 

Sure.. car is happy using these (for now)


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