Changed a set of PFR6B-11C for ZFR7F-11 today. ZFR are copper plugs, so probably change them every time I do the oil but for £2 each, who cares?

 

For comparison, both plugs are 11.5 mm from base of threads to the top of the metal 'shroud' around the insulator. ZFR are 2mm longer from top of shroud to top of firing electrode. Think length wise this puts them between PFR6B-11C and PFR6B-11B.

 

The plugs I took out had definately overheated (insulator v. white and no deposits at all, electrodes glazed) so it's probably worth going up to 7's.

 

Seems to be running OK on 0.8mm gap, but didn't go for a long run because I left the oil cap off!!!

copper electrode plugs are more prone to damage from high temperatures & detonation associated with turbo charged engines. the money you saved on the plugs will look very small indeed if you need an engine rebuild!!

 

id never fit anything other than platinum or iridium plugs. not woth the risk IMO.

 

-11 plugs are supposed to have a 1.1mm gap, so your probably down on power too if youve closed them up.

Wasn't a case of trying to save money, just couldn't get a platinum or iridium plug of the right dimensions in 7 heat range. PFR6B-11B now discontinued, NGK irridiums are too short. Not looked into HKS.

These plugs are what some of the big US and Jap tuners recommend.

Closed down to 0.8mm so the spark can form at high boost. Larger electrode surface area than plats so need smaller gap with same spark energy. Can probably play with the dwell/charge settings in the ECU but haven't tried it.

Originally posted by Paul C

copper electrode plugs are more prone to damage from high temperatures & detonation associated with turbo charged engines. the money you saved on the plugs will look very small indeed if you need an engine rebuild!!

 

id never fit anything other than platinum or iridium plugs. not woth the risk IMO.

 

-11 plugs are supposed to have a 1.1mm gap, so your probably down on power too if youve closed them up.

 

yes, but if he has detonation, then it will damage his plugs, which means they wont fire, which means no detonation, kinda like an auto detonation kill switch. i liek your thinking, jobs a guddun!!

Arghhhhh quick get here..you gonna need some help very soon!

 

Jeff TT

 

 

I can't beleive you fitted £2 plugs in a Z:confused:

Guys,

I've read quite a bit about plugs on here, and I know there are a couple of differing trains of thought, but those of you who have ended up with a strong allegiance to a particular plug, would you care to post details, including where you can buy them and for how much?

 

Being as everyone seems to sell plugs in 4s and I think I'll need 6, is there not some merit in organising a group buy here?

I can't beleive you fitted £2 plugs in a Z

 

Just thought I'd give it a try. From speaking to alot of people who are very knowlegable on this sort of thing (people who build proper race engines) 99% of what's said about spark plugs is rubbish.

 

OK plats/irridiums last longer and give more concentrated spark but that's it. It's fine to say irridium resists temp more etc. but how much of the plugs is actually irridium? A tiny part right at the end of the electrode. Other than that small part, the plug construction is identical!!

 

Worst case here is that the plugs won't last long, or will foul up because they're too cold. I tend to do compression test every time I service anyway, so I'm taking the plugs out.

Originally posted by John Dixon

Just thought I'd give it a try. From speaking to alot of people who are very knowlegable on this sort of thing (people who build proper race engines) 99% of what's said about spark plugs is rubbish.

 

OK plats/irridiums last longer and give more concentrated spark but that's it. It's fine to say irridium resists temp more etc. but how much of the plugs is actually irridium? A tiny part right at the end of the electrode. Other than that small part, the plug construction is identical!!

 

Worst case here is that the plugs won't last long, or will foul up because they're too cold. I tend to do compression test every time I service anyway, so I'm taking the plugs out.

 

 

That is your oppinion that 1% are right in what they are saying,at the end of the day you could fit diesel heater plugs if you wanted.

Originally posted by John Dixon

Worst case here is that the plugs won't last long, or will foul up because they're too cold. I tend to do compression test every time I service anyway, so I'm taking the plugs out.

 

........or your pride and joy (well mine anyway) will run like a sack of shite. Its just not worth the risk.

 

For me, oil and plugs.......treat the Z! Get the best you can.

All I'm saying is that it's worth a go. If the car runs crap after 1000miles then I'll pull them and go back to plats or try HKS or something.

I'm just happier knowing that I've got 7's in there as a safety measure against detonation, remember the 6's I took out HAD been overheating, and the main cause of detonation is pre-ignition off a plug tip that is too hot, that's why most race engines use surface discharge plugs - no earth electrode as a hot spot.

Does anyone know a 7 range platinum of the correct dimensions?

Originally posted by MAC 1

That is your oppinion that 1% are right in what they are saying,at the end of the day you could fit diesel heater plugs if you wanted.

 

LMAO!! dont be silly mac, the thread size is far too small!! :D

Nigel ,

The best place tobuy the plugs are courtesy Nissan in Texas.

6 plugs wth shipping and tax will cost you just over £60.

Here the plugs retail form nissan at about £70 - £80.

 

I have a set of 11B's that I have never used. Bought them as spares. Still boxed and sealed. £50 if anyone wanted them, free delivery.

I'm really struggling to see how these plugs could ruin your engine??? :confused: If they do get 'eaten' they errode from the sharp edges anyway so the electrode will just get shorter and shorter....

 

CheerZ,

 

Andy

Originally posted by andyduff

I'm really struggling to see how these plugs could ruin your engine??? :confused: If they do get 'eaten' they errode from the sharp edges anyway so the electrode will just get shorter and shorter....

 

CheerZ,

 

Andy

 

Oh dear Mr Always right is wrong yet again! Find out what happens to a plug that breaks down under serious heat conditions.:rolleyes:

Yeah, but kind of my whole point is that these plugs are colder than the standard platinums so will run at a lower temperature. If these were going to melt from heat, then the copper portion of the ground electrode on the platinum plugs would melt too, it's the same material.

Plugs usually break up from detonation that cracks the ceramic insulator, or bad gapping.

Just for you Duffer!

 

 

 

If the tip temperature is higher than 850°C the spark plug will overheat which may cause the ceramic around the center electrode to blister and the electrodes to melt. This may lead to pre-ignition/detonation and expensive engine damage.

Originally posted by John Dixon

Yeah, but kind of my whole point is that these plugs are colder than the standard platinums so will run at a lower temperature. If these were going to melt from heat, then the copper portion of the ground electrode on the platinum plugs would melt too, it's the same material.

Plugs usually break up from detonation that cracks the ceramic insulator, or bad gapping.

 

 

That is why these are the safest plugs to use;)

 

 

 

The Iridium alloy is used because of its durability and reliability. On an average plug, a narrow core typically shortens life span of plug but with the intense durability of iridium there is no sacrifice in any longevity. With a high melting point of 2454 degrees C, opposed to the 1769 degrees C of white gold, the electrode can tolerate the high levels of compression and minor knocking without any deterioration. A nickel coating on the housing also prevents the spark plug from premature deterioration. The Iridium plugs are available for multiple applications and offered in “colder” heat ranges of 7 and up and specifically for rotary, heat ranges of 9 and up are offered.

Originally posted by MAC 1

Just for you Duffer!

 

 

 

If the tip temperature is higher than 850°C the spark plug will overheat which may cause the ceramic around the center electrode to blister and the electrodes to melt. This may lead to pre-ignition/detonation and expensive engine damage.

 

Errrr yeah but thats what heat grading is! NOTHING to do with the material the electrode is made of.... Its the detonation from running too hot a plug that causes the damage NOT the wrong plug material.... ALL ABOUT HEAT RANGE OF THE PLUG.

 

CheerZ,

 

Andy

It stops sparking !

 

Originally posted by MAC 1

Oh dear Mr Always right is wrong yet again! Find out what happens to a plug that breaks down under serious heat conditions.:rolleyes:

Exactly, the HKS sales pitch basically says that the advantage of irridium is to provide a narrower electrode, and thus allow a wider gap. If the ceramic degrades at 850°C then it dosen't particularly matter what the mp of irridium is unless you get alot of localised heating around the tip (possibly its heat transfer coefficient isn't very high and this is the case, don't know).

As duff says, a properly heat ranged plug should not overheat so the problem goes away.

eeeeee champion!!!

So all the newbies like me remain tremedously confused!

 

Mac, please tell me the spec, supplier and price of the iridiums you use (if I got that right that is!)

 

and Stuart, why would anyone sell a set of perfectly good plugs if they intend to keep the car past the next plug change?

 

 

;)

 

Actually, I'm quite interested, but I have no idea if these are the plugs everyone is slaging off or the dogs gonads!

 

Every post I read gets me more confused

 

SO - here;s the challenge. If you have a modified car with a chip, induction kit and extra boost, AND have a set of replacement plugs that have lasted more than a couple of miles, please tell me all about them!:D

This could be a topic for the new FAQ thread. It seems to come up on here quite a lot.

 

We could have three versions:

 

The Nissan recommended plug

 

The "armchair mechanics recommended plug

 

And the "just stick any old sh*te in" plug

Originally posted by NigelBoyd

and Stuart, why would anyone sell a set of perfectly good plugs if they intend to keep the car past the next plug change?

Beacuse I have only just changed my plugs about 2,000 miles ago and have 58k left until the next plug change. I would prefer to have the money to spend on body kit :D :D

 

Originally posted by NigelBoyd

Actually, I'm quite interested, but I have no idea if these are the plugs everyone is slaging off or the dogs gonads!

No these are good en's mate, I think the £2 plugs are getting mullered here. :D

Ask around ;)

Originally posted by NigelBoyd

So all the newbies like me remain tremedously confused!

 

Mac, please tell me the spec, supplier and price of the iridiums you use (if I got that right that is!)

 

 

Ok got them from here not too far away from you;)

 

http://www.grasshopperprosport.co.uk/Pages/Location.html

 

They are HKS but not sure on the price:confused:

 

 

However I would not fit £2 plugs in my lawnmower:D;)