AGH1965 said:

Mick, are you saying that even the NGK part code was identical? I thought that you meant that the plugs themselves looked identical, but that the part code was different. What was the number at the end? Does this match with the gap you measured? I'm not familiar with the 25thou you mentioned. Or is that 0.025 inch?

Click to expand...

I'm saying that the part codes were different.
The original ones ............... and I'm sure the plugs I took out were the ones fitted from brand new were NGK 55233997

The new ones I've put in are NGK 55242187

Old and new plugs looked identical but the old ones looked old and tired of course.

The gaps I can only measure with Imperial feeler gauges because they are the only ones I have at the moment.
"thou" is short for Thousandths of an Inch.
ie 1 thou equals 0.001"

Old plugs were 31thou ............. conversion is 0.7874mm
New plugs are 25thou .............. 0.635mm

Conversions by courtesy of http://www.calculateme.com/Length/index.htm

Hope that helps.

Regards,
Mick.

Originally Posted by AGH1965
Wasn't there a NGK part code on the plugs? If so, the number at the end specifies the gap width in 0.1 mm. So, if the code ends with an "8", then the gap has to be 0.8 mm. What is right before this gap width number? Is it an "I", then it is an iridium plug; is it a "G", then it has a fine wire nickel alloy center electrode, which is cheaper.


Originally Posted by Mick F
Now I have the old plugs out, I see they are numbered 55233997
New plugs from Shop4Spares is 55242187

Does this make any difference?
They are visually identical.

Also the old plugs have a spark gap of 31thou (as measured with my elderly feeler gauges) and the new ones at 25thou.

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As a Twin Air owner I got (via FF) at least three different spark numbers 55233997, 55242187 and NGK ILKR9G8 for the same engine. I assume the first two numbers are OEM parts and the last Aftermarket, rights?
Personally I got the NGK ILKR9G8 (https://www.fiatforum.com/500/427296-socket-size-spark-plugs.html - post #11 ). As AGH1965 state it has a fine wire nickel alloy center electrode (G), but it still labeled as an Laser Iridium plug. Ref. NGK chart below:

I've fitted the ILKR9G8s to my TA. They are on the NGK website as being specially designed for the twinair engine.

TrevC said:

I've fitted the ILKR9G8s to my TA. They are on the NGK website as being specially designed for the twinair engine.

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Too late for me of course, but what benefit do those plugs give over the OEM specified plugs?

If you went to Fiat for a service, they would fit the same ones I've fitted. Mine came in a Fiat box labeled Ricambi Originali (Original spare parts).

Regards,
Mick.

Mick F said:

The original ones ............... and I'm sure the plugs I took out were the ones fitted from brand new were NGK 55233997

The new ones I've put in are NGK 55242187

Click to expand...

Mick, sorry for the misunderstanding! Please notice the disclaimer in my signature!

What you write here is the combination of the brand NGK and the FIAT part number. Since FIAT prescribes NGK part numbers in the owner handbooks, I assumed that these would be on the plugs, but in reality the FIAT part number is. I didn't know that. Mea culpa!

In some owner handbooks FIAT prescribes NGK PLKR9CI-8 plugs for the TA85; in other handbooks NGK LKR9EI-8. The NGK ILKR9G8 plugs mentioned by FoXy8 are in the owner handbooks prescribed for the TA105 though.

Some time ago I found on one of the NGK websites a cross reference list with both NGK part numbers and FIAT part numbers. Unfortunately I can't find it anymore.

Mick, I must confess I haven't noticed any difference in performance or economy since they were fitted. However, the guy that fitted them for me (I bought them so he had no vested interest) reckons that iridium plugs have about double the life of the standard ones.

TrevC said:

Mick, I must confess I haven't noticed any difference in performance or economy since they were fitted. However, the guy that fitted them for me (I bought them so he had no vested interest) reckons that iridium plugs have about double the life of the standard ones.

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If mine cost about 12 quid each and last 18,000miles, it must mean that the iridium plugs last about 36,000miles.

How does the price compare?
Is it worth the outlay?

Thanks,
Mick.

Mick F said:

Too late for me of course, but what benefit do those plugs give over the OEM specified plugs?

If you went to Fiat for a service, they would fit the same ones I've fitted. Mine came in a Fiat box labeled Ricambi Originali (Original spare parts).

Regards,
Mick.

Click to expand...

I did not found any specific details about spark plug 55242187 - just a statement that it's equivalent to ILKR9G8. Here what NKG say about ILKR9G8:

For the turbo-charged TwinAir two-cylinder 90bhp engine, NGK designed the space-saving ILKR9G8 spark plug which comes with a slim, long-reaching, 26.5mm M12 thread.
As the engine uses variable valve control to adapt the charging to the current driving conditions, the ILKR9G8 faces rapid charge movement and high cylinder pressures. To meet these requirements, it features a centre electrode with laser-welded Iridium tip.
Due to its exceptionally high melting point (2450°C) and hardness, this Iriduim precious metal is extremely resistant to spark erosion, and has a centre electrode with a diameter of just 0.6mm. This ensures unrivalled ignition reliability and engine efficiency.

The Laser Type is typical designer to last for 80 to 100 thousand miles ( I wold be more than happy if they last 40 thousand). I paid GBP 26.70 for one set (2).

Thanks.
I wonder why the plug is 26.5mm?
I bought a 26mm slimline socket and it fits mine ok - both old and new because they are 26mm.
Had I bought the Iridium plugs, my new socket may not have fitted?

i also wonder about the longevity of the Iridium plugs. It would be great if they lasted twice the distance as the OEM ones, as after all, they are similarly priced, but it seems a huge increase in distance.

Good to know. Thank you.
Mick.

Mick F said:

Thanks.
I wonder why the plug is 26.5mm?
I bought a 26mm slimline socket and it fits mine ok - both old and new because they are 26mm.
Had I bought the Iridium plugs, my new socket may not have fitted?

i also wonder about the longevity of the Iridium plugs. It would be great if they lasted twice the distance as the OEM ones, as after all, they are similarly priced, but it seems a huge increase in distance.

Good to know. Thank you.
Mick.

Click to expand...

The 26.5mm is the reference to the plug thread lenght.

FoXy8 said:

The 26.5mm is the reference to the plug thread lenght.

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Ah. That makes sense!
Back in the old days, the length was described as "reach".
You could buy long reach or short reach plugs for the same engine if I remember correctly. All to do with the efficiency or other otherwise of the ignition.

Just a quick measurement with a ruler of an old plug shows the thread length at 26 or 27mm.

Thanks,
Mick.

Regarding the cost of the iridium plugs, I paid about £28 for two. I had my trusted independent replace them as part of the major service, so only replacing them half as often saves a bit of labour, too. Obviously not a factor if you d.i.y.

TrevC said:

Mick, I must confess I haven't noticed any difference in performance or economy since they were fitted. However, the guy that fitted them for me (I bought them so he had no vested interest) reckons that iridium plugs have about double the life of the standard ones.

Click to expand...

Just done 60miles this morning, there and back to our daughter's house plus some shopping and stuff.

I reset the trip computer as I left home and it now records 53.6mpg.

This wasn't on any motorways or long dual carriageways, it was on small Cornish roads with 3rd gear foot down overtaking too.

I can't say for definite, but I reckon the economy is up about 5mpg. This is sticking my neck out here!

I'll be filling up later this week and then by the next fill-up, I should be able to see something solid on this.

Thanks,
Mick.

TrevC said:

Regarding the cost of the iridium plugs, I paid about £28 for two. I had my trusted independent replace them as part of the major service, so only replacing them half as often saves a bit of labour, too. Obviously not a factor if you d.i.y.

Click to expand...

Mick F said:

i also wonder about the longevity of the Iridium plugs. It would be great if they lasted twice the distance as the OEM ones, as after all, they are similarly priced, but it seems a huge increase in distance.

Mick.

Click to expand...

My previous Suzuki had OEM iridium plugs, they were taken out and the gaps checked annually, then refitted. The last service before I sold it they mentioned the gaps were getting a little large and I may wish to change them, the car had done 75k miles and was 8 years old. It didn't have any running or starting issues at all.

Sounds like that I should be fitting those iridium plugs in about 15,000miles time.
Could be three or more years yet, as we tend to do a little over 4,000miles a year.

Thanks,
Mick.

So my TA is coming for it's second service at 19.5K - I get it done annually. I thought I'd supply the plugs so I bought a set online from Micks Garage (yes they're Irish!!) and they quote NGK ILKR9G8 for the 85 and 105 TA which seems to match info on here however I notice in my manual they spec NGKPLKR9C8 for the 85 and NGK ILKR9G8 for the 105, so it seems they're saying fit Platinum to the 85 and Iridium to the 105. Presumably I'm ok to fit the ILKR9G8's to my 85. Has anyone else fitted platinums to an 85? Also I notice as above that the manual quotes C8 not G8 for the platinums - anyone know what the difference is?

Mercky said:

So my TA is coming for it's second service at 19.5K - I get it done annually. I thought I'd supply the plugs so I bought a set online from Micks Garage (yes they're Irish!!) and they quote NGK ILKR9G8 for the 85 and 105 TA which seems to match info on here however I notice in my manual they spec NGKPLKR9C8 for the 85 and NGK ILKR9G8 for the 105, so it seems they're saying fit Platinum to the 85 and Iridium to the 105. Presumably I'm ok to fit the ILKR9G8's to my 85. Has anyone else fitted platinums to an 85? Also I notice as above that the manual quotes C8 not G8 for the platinums - anyone know what the difference is?

Click to expand...

I've fitted the ILKR9G8s to my TA85. They are specially designed for the twinair engine. Please ref this tread post #62 for detail spark plug codes.

The original/factory plug fitted was labeled LKR9EI-8. Her is a photo of the old original one:





Do not forget to replace your Air filter too - at regular interval. My old Air Filter due my first service look like this:




(Photos of new plug and filter: https://www.fiatforum.com/500/427296-socket-size-spark-plugs.html
post #11 )

FoXy8 said:

Do not forget to replace your Air filter too - at regular interval.

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Your air filter is filthy!

The best thing to do, is to LOOK at your air filter at regular intervals, not actually replacing it unless it's dirty. It's a very simple job to check on them.

I looked at ours at 18,500miles and it was almost perfectly clean. I left it in place, and I'll be looking at it again in the spring. When it needs replacing, I think I'll be buying a KN filter.
http://www.knfilters.co.uk/search/product.aspx?prod=33-2981

Cheers,
Mick.

Mick F said:

The best thing to do, is to LOOK at your air filter at regular intervals, not actually replacing it unless it's dirty. It's a very simple job to check on them.

Click to expand...

:yeahthat:

DIY owners should change the air filter on condition, not mileage. A lot depends on the environment in which the car was used, and also (think about this one) it will last longer if you get better fuel economy than average .

Interesting to read this thread as I am picking up a 2011 Twinair on Wednesday.

Apologies if these questions have been answered already.

1. Am I right in thinking Twinair already have Iridium plugs? If so, is there something better that they can be swapped for? Anyone recommend any in particular?

2. I have a spark plug socket which isn't magnetic but easily got my 1.2 plugs out the other day. If it fitted the 1.2 will it fit the TA plugs?

3. Apart form mapping is there any way of beefing up the TA?