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jetjr

NGK Iridium plugs - anyone?

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Ive found a source in US that can land DR9EIX plugs here for around $10.50 each

 

Anyone else interested? PM me.

 

 

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From the other "Fouled plugs" thread seems $15 ea on special @ SCAuto

 

Some were bought for $12.75 ea from UK

 

So this $10.50 looks cheap.

 

Sould last way longer than conventional ones, which are around $6 ea locally I think

 

 

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From the other "Fouled plugs" thread seems $15 ea on special @ SCAutoSome were bought for $12.75 ea from UK

 

So this $10.50 looks cheap.

 

Sould last way longer than conventional ones, which are around $6 ea locally I think

I was talking to my son who is the spare parts manager for a Ford dealership about these plugs. He says they last about 4 times as long as the standard plugs but cost about 6 times as much. So economically not justified from his point of view. Maybe the advantage is the more potent, more reliable spark, if that is indeed the case.

 

Pud

 

 

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Yes thats wht I heard too, theres guys having them in for 250hrs in JAbs with no probs

 

BUT at this buy it isnt even twice the price.

 

Seems $20 each is std price from Auto stores

 

 

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They may last 320 hours, but what will the standard plugs do. Most of us change plugs at 25 or 50 hours, but for all we know they may go on for 100 or more. Checking my maintenance log I see my inlet plugs have done 120 hours and exhaust plugs have done 40 hours. They still run sweetly.

 

 

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Use of iridium plugs.

 

IF the insulator is fouling and electrode wear is not your problem, why would you need to use the iridium plugs?

 

$10.50 is a very good price, but if you get the cheaper plugs at a good price also they are about $3.00. ea. IF you have 2 plugs per cylinder and they are close together (as in a Jab) and therefore do not have a large "retard" effect when one fails. What would be the chances of Two plugs failing in any ONE cylinder at the one time? The only problem that I have experienced over the years is due to LEAD. IF you have the time you can clean the insulators and regap the plug and re-use it. This is more likely when the plugs used are the "shielded" type at over $60 dollars ea. Nev.

 

 

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At 100 hrs I replaced all 4 exhaust plugs (I clean, check and adjust all 8 plugs every 50 hrs)

 

At 150 hours I replaced all 4 inlet plugs.

 

So now I have a mix of older and younger plugs all working well.

 

The idea is to have a safety margin with a younger plug in every cylinder if the older one starts to break down.

 

Works for me

 

regards

 

PS Plugs are retired after 150 hrs use.

 

 

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Iridium 4 me

 

320 hour now and I am aiming for 400 hour before changing them. I have a second set ready to go in when i notice any problems.

 

For me running Iridium, to some degree was not the hours of use. My understanding with jabiru's low ignition voltage, the fine point Iridium gives a better spark, in turn better fuel burning, less carbon and small increase in power. < hope

 

I wounder if a strong spark would help cold engine starts?

 

 

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Life (Plugs)

 

They should do that OK as it is only about half the equivalent life when used in an automative application. Aircraft application would require a more conservative approach, tho.. Since most Jabs run Avgas, what is the effect of the LEAD?. Since this builds up on the insulator, wouldn't this still be a problem with iridium point plugs? Resistor plugs are not a good idea with magneto's as the high resistance in the secondary coil circuit tends to cause point burning. ( I am aware that the Jab doesnt run points, but the principle still applies. A high resistance in the secondary circuit is likely to cause coil failure). Has anyone got the final word on that type (Resistor) of plug, for use in aircraft? Nev

 

 

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I don't think you can compare aircraft plugd to automotive operation. Even a racing car seldom has more than a few seconds of full throttle power. before the next corner. Whereas a plane can have 8 minutes easily to climb to say 4000', full throttle and less cooling air.

 

 

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They should do that OK as it is only about half the equivalent life when used in an automative application. Aircraft application would require a more conservative approach, tho.. Since most Jabs run Avgas, what is the effect of the LEAD?. Since this builds up on the insulator, wouldn't this still be a problem with iridium point plugs? Resistor plugs are not a good idea with magneto's as the high resistance in the secondary coil circuit tends to cause point burning. ( I am aware that the Jab doesnt run points, but the principle still applies. A high resistance in the secondary circuit is likely to cause coil failure). Has anyone got the final word on that type (Resistor) of plug, for use in aircraft? Nev

Hi Nev

 

I haven't seen any significant lead build up to date or any significant wear on the electrode area. Probably right size jets or better burn with iridium or just good luck. I keep a good ear on any misfiring and a good look at the electrode end as well. My aim to change at 400 hour or sooner to a new set of iridium. I have heard of one auto engine on avgas with auto ignition wearing the electrode super fast around 100 hours. I understand that not the case with Jab low voltage Honda mags. Cheers

 

 

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Wear On electrodes.

 

Theoy, I would put electrode erosion down to the level of current in the secondary circuit. The temps the plug insulators run at affects the lead build-up and you obviously have that right. Nev.

 

 

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The engine guy at Natfly last year (from Cessnock as I recall?) said not to even use plugs of different hours in the same cylinder. Can't remember the reason but he quoted a number of bad experiences he had noted. I know from my hot rod days that not only heat range but different types of plugs can change the burn time and power. In those days I got a bit more power out of Bosch Platinums. I notice even the difference in 100LL and mogas in my 2200 Jab engine( the mogas is smoother) so the engine appears quite sensitive. I think I would let the factory or some else find out before I fiddle with this mod!

 

 

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You mention platinum plugs. What is the difference between iridium and platinum plugs?

 

My car uses platinum plugs with a recommended replace period of 100,000Km. That's a lot of hours.

 

Phil

 

 

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Last call, Theres room for another 10 plugs in the parcels ???

 

 

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You mention platinum plugs. What is the difference between iridium and platinum plugs?My car uses platinum plugs with a recommended replace period of 100,000Km. That's a lot of hours.

 

Phil

Hi mate according to the denso web site- iridium is 8 times harder and 6 times stronger than platinum. It has a melting pot of 1200 degrees hotter than platinum. (just in case your not aware, platinum/iridium is the material used for the electrodes.I hope this helps :big_grin:

 

ps- i have mentioned this before, they have been known to on very rare occasions, to break off the electrodes when used at high rpm.(o.4mm thick). Its happened on a few high performance motor bikes.

 

 

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Iridium plugs still in boxes......

 

Hi People,

 

When I had a sporadic misfiring issue a few months ago, I got all enthused and bought a set from Ireland for roughly half the oz price (landed here) but haven't fitted them yet.... closed the air gap on the coils to .008 and the plug gap on the (10hours only) NGKs to .016 and it hasn't missed a beat since. Reluctant to disturb the sleeping dog! i_dunno How do you think the wider gap of the Iridium plug handles the weak electrical impulse from the jabiru coils? That's another thing that makes me reluctant to fit them, as they say not to alter the gap...... got a Bass Strait crossing coming up in May, so have to decide whether to change them or not.......

 

Jim

 

 

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Have found a Us based company that supplied spark plugs delievered to Aussie for $9.18 Aus. The price will depend on the current exchange rate. His details are David Camp

 

[email protected]

 

 

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I bought some for my 3300 (price is $US) from .... was about half the local price

 

12-DR9EIX $9.45ea $113.40

 

Shipping $25.00

 

 

Total $138.40

 

 

 

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Hello again...

 

Any thoughts on altering the gap?? Yoo hoo.... anybody done that at all? Or do they give a stronger enough spark that it's unnecessary?

 

Jim

 

 

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Guest terry

hi zodiac3813, I changed the gap on mine without any problem

 

 

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A friend found a US supplier for iridium plugs @ $7.40 each.

 

He's waiting to see if they will ship to Oz

 

 

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