KSA-Cossie

iTrader: (4)

As I know they're quite fragile !!

KSA-Cossie

iTrader: (4)

upski troops

Rs1

iTrader: (1)

All iridiums are pre-gapped aren't they?

stevieturbo

It is exactly same for gapping any plug, regardless of type.

You are never supposed to touch any of the spark surfaces on any plug. A gentle tap on a solid surface will close the gap. And a little tool to widen the gap if needed.

botters

iTrader: (2)

bash it against summat flat!

stu21t

i thought you are meant to run a large gap in the iridiums, isnt that the point in them?

i normally just put a feeler gauge of the correct size in the gap then just gently tap the tip on something hard

stevieturbo

If that's how it sounds, it's a surefire way to cause damage. Never do anything to cause trauma to the tips. Whether by bashing it, scraping it, whatever.

Iridium is firstly for long life, and secondly for better spark performance. You certainly arent meant to run a large gap. But if they perform better you may be able to run a larger gap than some other plugs.

But it will depend on ignition power available, boost used etc etc

KSA-Cossie

iTrader: (4)

Got w/s on my saph,I'm sure the old ones were set at 0.8mm

tabetha

As said don't bash on a flat surface with the feeler in, as the shock loading is transferred.
I just get the feeler I want, normally 0.6mm, then try it, no doubt the gap will need closing, so tap firmly on a hard surface I use the square bit on the rear of the vice, do this till the right gap, if you go too far use a small screwdriver resting on the edge of the metal part of the plug and pointing under the "arm" of the earth electrode bend up slightly.
Long life was the main aim of the iridiums, as iridium is actually a really crap conductor of electricity!!
tabetha

KSA-Cossie

iTrader: (4)

Cheers Tabs.

stevieturbo

Even little cheap halfords gap measuring tool as the tool for opening up the gap.

I prefer this type of tool than feeler blades too.

http://www.halfords.com/webapp/wcs/s...egoryId_165469

Stu @ M Developments

iTrader: (12)

If your going to use impact instead of a gapping tool, dont go crackers. They come pregaped at 0.7mm and will work ok in any cosworth with Wasted Spark at that gap.

Iridium is not the best conductor of electricity as Tabs says, but there is as always, a much bigger picture...

Iridium is much harder, much stronger and much denser than any other spark plug electrode material and consequently it can be manufactred to operate with much smaller tolerances. Your average surface discharge centre electrode is around 2.5 - 3mm. The Iridium ones we sell are 0.4mm, this means you can fire out a sucessfull spark with both less voltage AND a bigger plug gap, and when it comes to spark plug gaps, bigger IS better ladies.

The larger the kernel that is generated by a spark jumping the electrode gap, the more likely and effective the fuel burn will be, and the smoother the engine will run because the larger the spark gap that’s exposed to the air / fuel mixture, the easier it is to initiate combustion of it when we need to. This translates directly into improved throttle response and in some cases more power. (Only where your hydrocarbons are high at peak power and a better spark reduces them of course)


Also remember this usefull fact for all you weekend tinkerers, Iridium plugs dont need to be regapped. EVER.

KSA-Cossie

iTrader: (4)

Magic , I'll just fire them in at 0.7 then Stu

CosworthGuy

Slightly off tpoic. whats peoples opinions on the correct gap for ford plugs. car is a 2wd 3door running stage 1. just bought some new ones and want to knw everyones opinions regards gap sizes

pete mcrash

iTrader: (1)

ffs....has everyone forgot the most important thing when gapping spark plugs...????












IT MUST BE DONE NAKED
Idiots...........

Stu @ M Developments

iTrader: (12)

Around 290bhp we normally set the plugs to around 0.75 mm if everything is in good order.

Around 340bhp we normally set the plugs to around 0.70 mm if everything is in good order.

Around 380bhp we normally set the plugs to around 0.65 mm if everything is in good order.

400 BHP and upwards we normally try to keep up at 0.65 but will begrudgingly drop them to around 0.60 mm if everything is in good order.

From there on upwards we recommend a better ignition system full stop as plug gaps below 0.60mm are poor but be prepared to drop them down to 0.55mm with big power if you cant get a better ignition system.

Please note that the BHP itself does not actually cause misfires, its cylinder filling and thus most misfires will happen around peak torque when the engines VE is at its best. RPM alone only causes issues through like of coil charge time, so for this and other technical reasons the above is a just a guide and would be totally wrong on say a 280bhp / 400ftlb restricted rally engine.

RSGARETHW

iTrader: (3)

prefer ngk9's myself kev

KSA-Cossie

iTrader: (4)

Fucker

SiST

iTrader: (1)

Thanks Stu - saves me having to read the rest of the topic

Ima Racing

iTrader: (1)

Never adjust an iridium plug they are designed not to be touched, if u do u risk a strong chance of tip falling off and fucking engine. Be warned.