Spark Plugs

[Zed2k]

Can anyone recommend an uprated spark plug for my Engine as it seems to choke up a bit after idling for a while in traffic.
My engine is a L28 with skimmed P90A head stage 2 cam and triple Weber 40s also a 6 into 1 header and 280zx dizzy.
Any advice would be great thanks.
Nick

 

[Mr.F]

First - don't mess with anything but NGK plugs.
Second - the 280ZX ignition set-up requires a 1.1mm gap plug. NGK part# BPR6ES-11 on a standard car.
Three - are you using the 280ZX coil (or equivalent performance part which does not require a ballast resistor) with the distributor and have you removed / by-passed the Z coil ballast resistor?
Four - the NGK part number indicates heat range - you might want to move up to a 7 or even an 8 in extreme cases, i.e BPR7ES-11 or BPR8ES-11.

Even on modified cars, the 280ZX distributor / coil set-up provides a superb spark, excellent mixture burn and rarely needs to go beyond a 7 series unless something else is wrong.

 

[Zed2k]

Thanks mike I'm using the 280zx coil as well so by passing the resistor, I'll try the 1.1mm gap and maybe move up to a 7 plug thanks.
<img src="http://www.zclub.net/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=''>

 

[ZVOITURE]

I was under the impression the higher the number the COOLER the range of the plug is. &nbsp;I understood BPR6ES to be the 'recommended' plug, and the 7 was a bit cooler and the BPR8ES an even cooler range. &nbsp;I think there is sparkplug.com or something like that which explains everything in great detail. &nbsp;I use BPR7ES. &nbsp;And yes, spread that gap out! &nbsp;I gap mine at 40.

steve77

 

[Mr.F]

The NGK number refers to the plug temperature: low number = "hot" plug and higher number = "cold" plug. The reference is really to the plugs ability to resist the heat of the engine. Thus a hot running engine requires a "cold" plug and vice versa. If you compare NGK plugs from an equivalent range, the "cold" plug will have a thicker outer wall compared to the "hot" plug, ie. greater ability to soak up the engine heat. Thus a plug has a heat range in which it will work optimally and outside of that range performance of the plug will fall off.

Fouling of plugs may also be due to centre electrode / insulator projection - the more projection, the more susceptible to heat and the more free from fouling.

 

[ZVOITURE]

Very nice, Mike. &nbsp;Thank you for explaining that. &nbsp;I never really understood why a 'cooler' plug was for a hot engine. &nbsp;I thought it had to do with how it fired or something....Now it makes perfect sense.

steve77