DarrenW
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| posted on 3/1/07 at 04:14 PM |
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Spark Plug grades
Whats the crack ref spark plugs? Does anyone have an article or advice on what the grades are and when you should use them. Im thinking as relevant to
a pinto. Ive always used 6's but was told 7's might be a bit better.
What about the makes. In particular NGK vs Champion.
Does it really make any difference in practice?
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Big Daz
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| posted on 3/1/07 at 04:27 PM |
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IIRC from my Scooby turbo & Nitrous days the higher the number the cooler they run (more heat they can withstand)
I was using 9s in my race 205GTI with nitrous as the 7s kept getting fried to a crisp due to the increased combustion heat.
I have a preference for NGK but for no particular reason 
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NS Dev
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| posted on 3/1/07 at 04:28 PM |
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Hi Darren, hope all is well, happy new year!
Yes, plugs make a huge difference, not so much in terms of power as much as whether the engine works or not.
When you consider what the plug has to do, the temperature range is absolutely critical.
There will be tons of info out there on the subject, but you basically need a plug that runs warm enough to keep clean (burn off its own carbon
deposits) but cool enough not to cause pre-ignition.
I know you know enough about all that so won't go further.
In practice on a pinto, typically one grade "cooler" or "harder" is a sensible move.
You will know if its too cool as they will foul up and you'll get misfiring when the engine is cold.
Look on the burton website for the available plugs, and go one colder than std and you will be fine.
As an aside - on out and out race engines, especially ones that don't burn too cleanly due to chamber shape etc, plugs can be a real pain. I
knew of a cosworth YB engine a few years back running 285hp from 2 litres normally aspirated, that needed 3 different sets of plugs to warm up, hot
ones first, then cooler, then cooler still. It would not even fire for more than a few seconds if you tried the cold ones from first off, and the hot
ones had apparently already claimed a piston and headgasket! (engine was an absolute marvel once warm, I hasten to add, beautiful tarmac rally motor
in a mk2 escort)
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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DarrenW
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| posted on 3/1/07 at 04:38 PM |
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Im very well Nat thankyou. Happy new year to you, i hope its a very prosperous one (money and wins).
Ive just picked up a set of 7's so will give them a try. I had to get Champions this time as factors didnt have NGK in.
I havent touched the car for a couple of weeks (could hardly walk most nights so working was a no no!!!). Moving house at the weekend so thought it
might be good idea to get engine chucked in, hence while im on might as well try a plug change.
Just need to get new tiny garage organised with cupboards etc so i can get on with carb change and megajolt swap (trigger wheel fitted and sensor
bracket made already).
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NS Dev
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| posted on 3/1/07 at 04:41 PM |
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PS, its the plug shape that makes the difference between heat grades, the longer the heat path the hotter it is, the short heat path tips give cooler
running.
PPS, in my experience manufacturer etc makes little odds, its mainly down to whether you can get the right grade ata decent price from a stockist.
Don't fall for multi electrode snake oil plugs. These just wear out slower and aren't available in many grades.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Hellfire
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| posted on 3/1/07 at 04:43 PM |
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quote:
Originally posted by DarrenW
Ive just picked up a set of 7's so will give them a try. I had to get Champions this time as factors didnt have NGK in.
As NGK have over 8 million plugs in stock on a rolling stock basis - there is no excuse for your factors NOT to have the best plugs in the world...
Steve
PS I am biased...
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NS Dev
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| posted on 3/1/07 at 04:46 PM |
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7's should be fine, if you plan on going to the rolling road, prob good to have some 8's ready just in case.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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DarrenW
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| posted on 3/1/07 at 04:49 PM |
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I was wondering when you will be along Steve
I did a search by the way and read some of the articles posted. The long article relating to bike ignition systems was interesting.
I wonder if i need to fit zetec style platinum tipped plugs when i convert to megajolt? Its a fair bet i wont!
I only paid £1.34 +VAT each fo rthe Champions so it wont break the bank.
It was a long time ago since i last fell for the "£25 for 4 std plugs that look special with 4 electrodes in fancy packaging" tricks from
Halfords.
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mookaloid
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| posted on 3/1/07 at 05:23 PM |
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I use NGK 7's - the 6's tended to foul a bit
NGK always seemed less prone to problems than champion in my motorbikes so I tend to stick with NGK
- Just my 2p worth 
Cheers
Mark
"That thing you're thinking - it wont be that."
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MikeRJ
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| posted on 3/1/07 at 05:39 PM |
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Be very carefull! Champions numbering system is very odd, and backwards compared to NGK's i.e. a higher number is hotter for Champion and
cooler for NGK.
None of the different plug brands use the same heat scales as far as I know.
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Stu16v
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| posted on 3/1/07 at 08:43 PM |
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quote:
Originally posted by MikeRJ
Be very carefull! Champions numbering system is very odd, and backwards compared to NGK's i.e. a higher number is hotter for Champion and
cooler for NGK.
None of the different plug brands use the same heat scales as far as I know.
Phew! Just about to post the same myself...
Dont just build it.....make it!
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DarrenW
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| posted on 4/1/07 at 09:35 AM |
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Oh crap!!!!!!
Blows that theory out of the water then. Looks like ill have to take the champions back and try and get some NGK's.
I found this link to manufacturers codes.
http://www.spark-plugs.co.uk/pages/technical/spark_plugs_technical.htm
Thanks for the reply Mark. Ive often seen the NGK 6's foul up a bit but put that down in part to incorrect mixture as well.
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NS Dev
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| posted on 4/1/07 at 09:38 AM |
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doh, I was looking at the NGK numbers!!!
Have used champion plugs before and never even noticed somehow!!!!
The XE only ever uses std plugs so that's prob why!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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DarrenW
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| posted on 4/1/07 at 12:28 PM |
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Here is quite a good article from NGK site on heat ranges etc.
http://www.ngksparkplugs.com/techinfo/spark_plugs/techtips.asp?nav=31000&country=US
I found another site that has concluded that the NGK APR6FS plugs i was using before (and recommended as a std pinto plug) are equivalent to Champion
RF7YC. So my theory on a std heat range numbering system being employed and me just buying a one grade cooler set of plugs is incorrect.
Research has shown that the main visual difference in the heat ranges is the amount of insulator visible in the nose. Both plugs i have are about the
same. Cooler plugs have less insulator visible and hence take away the combustion heat better to maintain the std nose operating temp despite hotter
environmental conditions (ie higher compression, forced induction, harder driving etc).
At least now i know;
a. I have a set of new std plugs to get me running,
b. if i want a cooler set dont go to that motor factors and try and find NGK 7's.
Thanks to all for the help.
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