Pulled my spark plugs recently (platinum NGK PFR5B-11) and noticed that the ceramic surrounding the electrode tip is a reddish brown. I'm not sure if this is a problem as the car runs really well at idle and under boost. I'm wondering what has caused it. I think these plugs are actually for an NA although the previous owner installed these. I don't know how many kms they've done. The car did have a problem with the driver's side exhaust cam sprocket being incorrectly installed which caused the exhaust valves to close slightly late. This was fixed last year. Could this be the reason for the red/brown ceramic? BTW - I've ordered some platinum NGK PFR6B-11B plugs from Coz and have a new set of copper BCPR6ES plugs to choose from. Not sure which I'm going to use.
have you ever put an octane booster additive in the fuel tank? The last time I did my plugs got covered with a brown/coppery looking coating.
You reckon this colour is ok then? Sorry I can't get pics at the moment, the plugs are back in the car until I decide which to fit, or even use the existing ones. Probably best to go a bit cooler with running 12/13 psi boost
The previous owner may have added booster, but I haven't. Probably not, she was stock as a rock when I got her.
use the copper plugs, you should be pulling plugs to check whats happeing as often as the coppers need replacing anyway
plugs' ceramic bits are supposed to discolour. if they stay white like new it suggests lean running conditions.
5 heat range plugs are a hotter plug, you should be running 6 (stock) or 7's if you have a bit of boost screwed in.
So do you agree that 6 heat range plugs will do the job for stock turbos running 13psi boost. Conceptzperformance and other websites state that the platinum NGK PFR6B-11B are recommended for all daily driven 300zx's running less then 15 Lbs of boost on stock turbos because of their excellent spark and long lasting(60K).
A stock zed with a little boost will be fine with standard heat range plugs. 6's it is. Your choice whether you go coppers, platinum or iridium. I would use iridiums in your situation.
Iridiums? Wasn't expecting you to say that. My extensive research on the net today throws up a lot of different views. One that stuck with me was the idea that iridium was a crap electrical conductor compared with platinum or copper. It is suggested that the copper or platinum provide a better spark for our ageing coilpacks. I'm not really interested in longevity as I only do about 5000kms per year.
everyone has a different opinion, maybe you should try them all before making up your mind. platinum plugs these days tend to be more expensive than bloody iridiums so i haven't used them since my car was stock. have used coppers on and off. they go off too quickly and call me lazy but i CBF changing every 5000ks. when i had coppers i was actually changing just before 5000k intervals as i can actually feel the rougher idle and reduced performance. when i step away from coppers i use iridiums and they definitely idle smoother and i prefer them over anything else. the copper purists probably won't agree but doesn't bother me. my car likes it, that's all that matters.
As someone who is constantly modifying my tune and engine, coppers show up mild detonation pretty clearly, and will fail before other more costly engine parts in the case of severe detonation. The only reason I use them, otherwise iridiums and platinums are a better plug.
won't argue with that andy. my tune is set and done. since i'm happy with it i've left it alone since '08. i don't make big power, the car is a daily so when you make changes i can sort of feel the difference straight away. iridiums feel much better than coppers. the only hardcore copper fanboy on here is 300zxt who gives a spiel about how you can't tell the difference and if you don't run coppers for their diagnosis advantages you shouldn't own a zed.
Well I fitted the coppers this morning and the car feels strong and smooth as it did before with the platinums. I only swapped out the platinums because they are a 5 heat rating and I am running some boost so 6 rating is better. The platinums (NGK PFR5B-11) are still fine and have probably only done less than 10,000 km. If anyone wants these they are yours for the price of postage. :zlove:
I can't find the article/post at the moment, but there was something mentioned about the 11B plugs not being suitable for our J-spec TT's(something about length I think).
Found it: http://www.300zx.net.nz/articles/MainLib/Theory/sparkplugs.htm 11B plugs recess further into the heads but I've never seen anyone who's had them or used them.
Well guys what do you reckon? That article seems to support fitting the 11B plugs if running higher boost. I hope they are good for a zed running 13 psi boost, pod filter and cat back zorst upgrade. The NGK PFR6B-11B plugs are recommended by Coz: http://www.czp.us/Cart/description.php?II=291
That's a US part. Jspec zeds as chili pointed out are supposed to use the same part # NA or TT. Unless you're pushing 18psi+ (you wouldn't be anyway as it just makes more heat with stock turbos), your spark won't blow out under boost and stock plugs are perfectly fine. Far as I know the standard PFR6B-11 are discontinued and replaced by PFR6G-11. Only the US still has the PFR6B-11B and IMO I don't think you'll need it.
Mike z32 is correct. The PFR6G-11 uses a later firing end contruction tecnique than the PFR6B-11. You may still get the B but use the later plug where you can. In your case I would gap them down a little to 0.9mm.
