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A basic guide to Spark Plugs.

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Old 07-25-2010, 04:54 PM
czar
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A basic guide to Spark Plugs.

Ok guys, I see the same questions asked over and over about spark plug selection and fitment, so I hope this information below helps.

The first generation R50, R52, R53 petrol models were fitted from the factory with the NGK: BKR6EQUP with the EXCEPTION of the R53 JCW this was fitted with the NGK: BKR7EQUP.

R50: NGK: BKR6EQUP tightening torque: 25-30nm (18-21.6 lbs/ft) thread diameter/pitch M14 x 1.25 socket size 16mm, electrode gap: pre set, heat range 6

R52: NGK: BKR6EQUP tightening torque: 25-30nm (18-21.6 lbs/ft) thread diameter/pitch M14 x 1.25 socket size 16mm, electrode gap: pre set, heat range 6

R53 Cooper S: NGK: BKR6EQUP tightening torque: 25-30nm (18-21.6 lbs/ft) thread diameter/pitch M14 x 1.25 socket size 16mm, electrode gap: pre set, heat range 6

R53 JCW/GP: NGK: BKR7EQUP tightening torque 25-30nm (18-21.6 lbs/ft) thread diameter/pitch M14 x 1.25 socket size 16mm, electrode gap: pre set, heat range 7

All the above mentioned NGK spark plugs have a Platinum ring around the electrode tip, NGK also provide the following with an Iridium electrode tip, however be careful as the following have a tip projection of 1mm extra in length over the above!

BKR6EIX Iridium tip, this is an alternative replacement for the BKR6EQUP with the same heat range (6)

BKR7EIX Iridium tip, heat range (7) this is 1 heat range colder than the BKR6EIX

BKR8EIX Iridium tip, heat range (8) this is 1 heat range colder than the BKR7EIX

The second generation R55, R56, R57 petrol models are fitted from the factory with the BERU: 12ZR6SP03 with the EXCEPTION of the Cooper S these are fitted with NGK: PLZBR7A-G, and the JCW are fitted with the NGK: ILZKBR7A-8G

R55: One/Cooper: BERU: 12ZR6SP03 tightening torque: 20nm (14.5 lbs/ft) thread diameter/pitch M12 x 1.25 socket size 14mm, electrode gap 1.0mm, heat range 6

Cooper S: NGK: PLZBR7A-G and JCW: NGK: ILZKBR7A-8G tightening torque: 15-20nm (10.8-14.5 lbs/ft) thread diameter/pitch M12 x 1.25 socket size 14mm, electrode gap: pre set, heat range 7

R56: One/Cooper: BERU: 12ZR6SP03 tightening torque: 20nm (14.5 lbs/ft) thread diameter/pitch M12 x 1.25 socket size 14mm, electrode gap 1.0mm, heat range 6

Cooper S: NGK: PLZBR7A-G and JCW: NGK: ILZKBR7A-8G tightening torque: 15-20nm (10.8-14.5 lbs/ft) thread diameter/pitch M12 x 1.25 socket size 14mm, electrode gap: pre set, heat range 7

R57: One/Cooper: BERU: 12ZR6SP03 tightening torque: 20nm (14.5 lbs/ft) thread diameter/pitch M12 x 1.25 socket size 14mm, electrode gap 1.0mm, heat range 6

Cooper S: NGK: PLZBR7A-G and JCW: NGK: ILZKBR7A-8G tightening torque: 15-20nm (10.8-14.5 lbs/ft) thread diameter/pitch M12 x 1.25 socket size 14mm, electrode gap: pre set, heat range 7

So with this basic information above out of the way, lets move along a little to what I have seen posted quite a few times,

Q1: What's the best spark plug for my Mini ?
Q2: Can I put Cooper S or JCW spark plugs in my One or Cooper ?
Q3: and JCW spark plugs in my S ?
Q4: and will I get any power performance gain in doing so ?

As you may have guessed the answers to the above questions are not straight forward, very basically the answers to questions 2/3 are YES, with a caution in understanding the effects a colder heat range spark plug may have when fit into a stock engine!
Question 4: is although the Iridium is seen to be the performance spark plug, the fitting of the Iridium spark plug itself will not give any power performance gain, many people report, that when they changed from Platinum to Iridium, they felt a livelier throttle response, in fact what you will have done is simply, renew old tired spark plugs with fresh new spark plugs, the ignition system now performing as it should do, thanks to the change of tired old, for new fresh, the material change in the case of Platinum to Iridium has played no difference! The other question (Q1) will be answered as you read on, Platinum and Iridium is used for it's hardness and resistance to wear, this gives longevity between service intervals, with Iridium being the harder of the two,
Iridium is 6x harder and 8x stronger than Platinum, Iridium has a very high heat melting point of 2,443 degree C, with all these factors taken into consideration, Iridium is generally thought of as being the best material for the electrode tip resulting in a fine wire spark plug, well in terms of less maintenance/extended service intervals then yes it is, however Iridium is a very very dense material and is a very poor thermal and electrical conductor, see chart below.

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Some of you may well be saying, Why use it at all if what we see/read here is true? As touched upon earlier, Platinum and Iridium are used for their ability to provide longevity between service intervals and the resistance to wear, especially Iridium, that's it.

Now that you have seen the thermal and conductivity chart, we can see that Silver is the best of all metals when it comes to thermal and electrical conductivity, so why not fit these instead of the more popular Platinum and Iridium? Well very simply, you would need a more regular maintenance schedule, unlike the Platinum and Iridium spark plugs, which can be fit and forgotten about for 20,000 miles + if you use or consider using Silver or copper spark plugs, remember these will require more frequent service schedule replacements than the Platinum or Iridium, if you are looking for more performance over longevity, or you track your Mini, then you should be aware and looking if not using other alternatives to Platinum or Iridium.

Now I've got you thinking, So what's the best spark plug for my Mini? That all depends on what you do with your Mini, and of course your budget, if your Mini is your daily driver and you rely and trust your dealer (they know best!) then you may as well stop reading now, if on the other hand your Mini is your daily driver come weekend warrior, or is just your weekend warrior, and you do your maintenance yourself then read on.

So your now thinking about the possibility of a better performing spark plug, with the Mini you must run a Resistor spark plug, if you were to run a non Resistor spark plug you will have issues with the electronic steering system and the electronic throttle (drive by wire system) So lets now forget about stock/standard Platinum and Iridium spark plugs, and concentrate on PERFORMANCE, if you want the best performance then you have to look at Silver or Copper, as you can clearly see from the thermal and electrical conductivity chart, these two materials are No 1 Silver and 2nd Copper, so you've upgraded your engine/fuel system/ignition system (wires and coil or coil overs in the case of those running gen 2 or converted your gen 1 to coil overs) and had your Mini tuned, why are you still running Platinum or Iridium spark plugs? the noticeable difference can be quite significant, when running Silver or Copper spark plugs, Just because these tend to be aimed at and marketed as Performance/Racing spark plugs, does not mean their sole purpose is for track use, however the term, Racing spark plugs, are generally just an indicator of the colder heat ranges available from the standard stock spark plug specified for your particular Mini.

The term spark plug heat range refers to the speed with which the plug can transfer heat from the combustion chamber to the engine cylinder head, it has been found the optimum combustion chamber temperature for petrol engines is between 500 degrees C – 850 degrees C when it is within this range it is cool enough to avoid pre-ignition and plug tip overheating which can cause engine damage, while still being hot enough to burn off combustion deposits which cause fouling.

The spark plug can help maintain the optimum combustion chamber temperature, when a spark plug is referred to as a “cold plug” it is one that transfers heat rapidly from the firing tip into the engine cylinder head, which keeps the firing tip cooler. A “hot plug” has a much slower rate of heat transfer, which keeps the firing tip hotter.

An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate racing fuels, or sustained use of nitrous oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70 degrees C to 100 degrees C from the combustion chamber!

The heat range numbers used by spark plug manufacturers are generally the higher the number, the colder the plug.

Do not make spark plug changes at the same time as another engine modification such as different injectors/timing changes different boost loadings from your chosen forced induction, as in the event of poor results, it can lead to misleading and inaccurate conclusions, an exception would be when the alternate plugs came as part of a single precalibrated upgrade kit. When making spark plug heat range changes, it is better to err on the side of too cold a plug. The worst thing that can happen from too cold a plug is a fouled spark plug, too hot a spark plug can cause severe engine damage!

This next little bit of information may not be of much use to many of you reading this, however for those that have the time and patience, then you may want to try degree orientation, (indexing) this is lining up the ground electrode with the inlet valve/s, this usually has a window of 45 degree, working from the direct central position alignment of the ground electrode with the inlet valve/s, getting this correct can be quite difficult, firstly you will need to mark the ground electrode position onto the spark plug hex head or porcelain body with a suitable marker, then unscrew the sealing gasket from the spark plug, you then need to place a flat Copper washer of a specific thickness of your choice directly onto the spark plug shoulder, then screw the sealing gasket back onto the spark plug, once you then install and correctly torque down your spark plug you will get an indication as to the general direction of the ground electrode in relation to your inlet valve/s, you may need to do this many times using + or - to your first installed washer thickness to get the ground electrode in the correct orientation to the inlet valve/s, this operation can give a small benefit in terms of performance, but generally this gain can only normally be read on the dyno or felt at the track, and such is the small gain it may not be worth your inconvenience, time or effort to do, however that said if you are looking for every possible FREE amount of performance gain, then it may well be worth your while!

Now all of the above information is just a very quick guide to spark plugs, there is a lot more I could and can add, however I hope it will help all who read this, understand a little more about spark plug selection and fitment for the Mini.
 

Last edited by czar; 07-27-2010 at 03:26 AM.
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  #2  
Old 07-25-2010, 05:22 PM
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Wow nice read! Thanks for the knowledge and effort!
 
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Old 07-25-2010, 05:59 PM
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Nice write up
 
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Old 07-27-2010, 01:53 AM
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Thanks
 
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Old 07-27-2010, 06:44 AM
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The OP is well versed in Spark Fu.
 
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Old 07-27-2010, 12:58 PM
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that was an outstanding write up and useful to me since I'm about to change plugs and going with Brisk Silver for my mini. thanks
 
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Old 07-30-2010, 09:41 AM
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Wow....I was completely oblivious to all of this. I thought Platinums and Iridiums were "The Best". Obviously, they are just longer lasting and require less maintenance of your vehicle.

Well, with the Mini's plugs being right at the top of the engine and easily accessible, I think I may go the silver route. How often should silver or copper plugs be changed as compared to platinum or iridium?
 
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Old 07-30-2010, 10:28 AM
czar
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Depending on what you use your Mini for, will depend on the interval between changes of your Silver spark plugs, but in general you should get 5-10,000 miles of good service from your Silver spark plugs, that said, if you change your oil at say 5-6,000 mile intervals, then at the very least take out your spark plugs and do a self evaluation as to their condition, if you are not too sure and maybe you have noticed a slight drop in performance or MPG, then this would be a good time to change them.
 
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Old 07-30-2010, 11:12 AM
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Ok...

So, therein lies the other question.....

Is there a difference in mileage from using different spark plugs? Are the silver/copper more sport based, but get worse gas mileage than the Platinum/Iridium?

Just curious as to whether or not it affects gas mileage.

Thanks for the quick response.
 
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Old 08-03-2010, 06:40 AM
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I am using a R50 (2006) Mini Cooper, AT. I also want to change spark plugs for better performance, such as a better livelier throttle response.

1) What silver or copper spark plugs do you recommend? and
2) How often do I need to change these spark plugs?
3) Same as "ViperGTS", whether or not it affects oil consumption?

Thanks!
 
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Old 08-06-2010, 07:03 AM
czar
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Silver and Copper spark plugs will wear faster than Platinum and Iridium, we all understand this now, right!

when Silver and Copper spark plugs are installed in favour of Platinum and Iridium, at first you won't notice any difference in MPG, that said, remember earlier, Silver and Copper wear faster than Platinum and Iridium!

The more wear to the ground electrode (increased gap) then the less effective the spark plug becomes, poor MPG.

So Silver and Copper spark plugs should really be changed more often than you would with Platinum and Iridium, as a rule of thumb change them or at least inspect and adjust the electrode gap every 10,000 mile.

As your in the USA I would recommend BRISK for your Silver spark plugs or NOLOGY, as for copper spark plugs any of the premium manufacturers.
 
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Old 08-07-2010, 12:30 PM
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Wow! Who new? I stopped by the local dealer this week for a set of BKR6EQUP for my '06S and was horrified! They had the nerve to ask $119 for a set!!!!!!!!! I try to support them, but that was the last straw. Online parts from here on. Autozone had them for about $6 each.
 
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Old 08-13-2010, 03:44 AM
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That's why they call them $tealer$hips. Great write up on spark plug information! Make sure your plugs are torqued to spec, especially if you do track days or routinely nail the boost!
 
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Old 08-23-2010, 12:07 AM
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Spark plug missile or fountain and an expensive repair.
 
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Old 08-23-2010, 11:56 AM
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Ok,

I picked up the NGK: BKR7EQUP for my car.

I noticed they aren't 4 prong like the other ones.....

Is this an issue? Will it cause any problems down the road?

Thanks!
 
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Old 08-23-2010, 03:07 PM
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Originally Posted by ViperGTS View Post
Ok,

I picked up the NGK: BKR7EQUP for my car.

I noticed they aren't 4 prong like the other ones.....

Is this an issue? Will it cause any problems down the road?

Thanks!
A very short and simple answer, NO, everything will be just fine.
 
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Old 09-09-2010, 11:18 PM
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Considering all the hoopla over recent spark plug designs, are the Bosch quad-tipped ones just hot-air advertising? Or do they really produce a better spark? I once tried Splitfire on my 2000 Intrepid and they didn't make the slightest difference in fuel economy although Splitfire claimed they would add an extra 1-2 mpg.
 
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Old 09-10-2010, 04:29 AM
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What happens is with 2,3 or 4 ground electrode spark plugs is, they don't necessarily provide a stronger spark, their advantage is the multiple ground electrodes can continue to provide a clean point for the energy spark if 1 or more points become fouled, unlike a traditional single ground electrode spark plug, when fouled will reduce or stop to allow the spark energy to jump the air gap.

If you want a stronger spark, from your stock ignition set up, then you must look at either Silver or copper, they require less energy to jump the gap, because of their excellent electrical conductivity.
 
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Old 09-10-2010, 12:20 PM
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I am still wondering....

If I switch over to silver or copper, will I see an increase in power or fuel economy?

It isn't difficult to switch them out and if I can get better fuel economy, it would be well worth it. Or, maybe even increased power....

Thanks for all the information, czar.
 
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Old 09-10-2010, 05:48 PM
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I don't know much about cars (yet), with the exception that since I brought home my first MINI 2 weeks ago, I have been visiting the auto parts store and reading manuals and forum boards on how MINI's tick.

Thank you, czar, for a great tutorial. Very informative....helped me feel more confident in discussions with mechanics.
 
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Old 09-14-2010, 06:43 AM
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When I used to drag race my '85 SS Monte Carlo, the best plugs were good old-fashioned AC Delco copper. I've long known Platinum and Iridium plugs are simply for longevity, but I did not realize the difference in conductivity between the metals until I read this thread.

For anyone interested in running a Copper alternative, NGK does carry BPR6ES and BPR7ES plugs. If you decide to run these, and memory serves, the regular service interval for copper is ~36,000 miles. If you are a maintenance-conscious driver, just check them at a predefined interval, such as every time you change your oil or rotate your tires.

One additional note. Both my old '02 MCS and my current '02 MCS actually came with BKR5EQUP plugs. A couple of mechanic friends have said that this change can be due to the climate for which the car is delivered. Both MINIs were initially shipped to the Hampton Roads VA area. I just don't recall if this plug heat range applies going south of here or north of here.
 
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Old 09-14-2010, 07:00 AM
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Aha! Now I understand why everyone likes Brisk plugs. They make them with a silver core.

From what I have researched, they have the same lifespan as copper plugs. For anyone interested:

Standard Cooper/S: BRSK-DR15S (non-projected tip), BRSK-DR15YS (projected tip)
Cooper S w/JCW or 15% pulley: BRSK-DR14S (non-projected tip), BRSK-DR14YS (projected tip)
Two ranges colder: BRSK-DR12S (non-projected tip), BRSK-DR12YS (projected tip)

Here is a Brisk products page with links to cross-reference charts: http://www.briskusa.com/products.htm. The DR series do have resistance built-in.

Here is a Nology cross-reference page: http://www.nology.com/crossref.html. Many of the Nology silver plugs are non-resistor style for maximum performance. This means you may get some noise from the engine in your stereo.
 

Last edited by JumpingJackFlash; 09-14-2010 at 07:46 AM.
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Old 09-15-2010, 02:04 AM
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this info are so detail. thanks czar.. thumbs up..
 
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Old 09-20-2010, 07:19 PM
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Great information. One question. Do I need to set the gap? How do I determine the proper gap for these plugs?

Thanks.
 
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Old 09-21-2010, 07:17 AM
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Originally Posted by hardiek View Post
Great information. One question. Do I need to set the gap? How do I determine the proper gap for these plugs?

Thanks.
What spark plugs are you referring too?

Most of the spark plugs come pre gapped, and so there is no need to set them, however it's not a bad idea to check them, but do NOT touch the fine wire electrode, with anything that you are going to adjust the ground arm, as this can lead to damage of the fine wire tip.
 

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