Spark Plugs - Gap and Parts Numbers

[fisherthewol]

Hi All,

tl;dr: Does the NGK IFR7X8G fit the CCZB engine? And will I need to adjust the gap on them?

Spark plugs are probably overdue on my Scirocco - bought in June and the service history suggests the last spark plugs were in 2016, 20k miles ago.
NGK's parts finder https://www.ngkpartfinder.co.uk/ suggests two possible parts for me, Platinum PFR7S8EG and Iridium IFR7X8G.

Autodoc, Eurocarparts and everyone else seems to be happy that the platinum plugs fit fine.
However no one, other than NGK themselves, wants to say that the iridium parts fit. Autodoc says they're only for a Megane; Eurocarparts seems to not stock them.
Hence I'm worried that NGK's parts finder has some data error. I've submitted a parts enquiry to autodoc, but I doubt they'll get back to me.
Does anyone have any experience and know whether they fit?
Similarly, the NGK spec sheet just says "pre-gapped". Autodoc suggests it has a gap of 3.5mm, I've seen some posts on here that suggest a 1mm gap is needed - any ideas? I'm not against adjusting the gap, but I'm under the impression that you can't do this on an iridium plug without damaging it.

Best,
Fish.

[fisherthewol]

I contacted NGK about it and have confirmed: PFR7S8EG / 1675 or IFR7X8G / 95820 are appropriate for the CCZB engine. The gap on the IFR7X8G is 0.8mm.


Here is the full reply from NGK:
Good morning Fish, thank you for your enquiry,

I can confirm that iridium plugs IFR7X8G (stock number 95820) are the correct plugs to use if you wish to upgrade.

The gap is pre-set at 0.8mm on these and we do not normally recommend adjusting the gap before fitting.

I am unsure where the 3.5mm gap size comes from, or why that would be suggested as it is much larger than how the plugs come as standard?

As long as your engine is in standard, unmodified condition - then either the standard platinum PFR7S8EG / 1675 or the iridium upgrade IFR7X8G / 95820 will be perfectly fine to fit as they come,

Kind regards

****** ******

[finetrond]

Indeed the gap is 0.8mm
There is a 3.5mm measurement on the webpage. Spark plug position, I'm not going to find out what it is.
Honestly I thought gapping it was more of a 2-stroke thing. Then again, I'm not a car mechanic.

[megatron-uk]

A 3.5mm gap is frankly enormous. Traditional gaps were given in thousands of an inch. I have never heard of anything requiring a gap that big.

Most plugs these days come pre-set.

[fisherthewol]

Hi All, thanks for the responses.

Yep, 3.5mm is massive - think I was a few winks short of 40 at the time.
A further email to explain myself with Niterra/NGK and that measurement is confirmed as the distance between the nut and the tip, or there-abouts - some dimension to do with fitting and not the spark-gap.

Yes most plugs come pre-set; however given that Autodoc believes the plugs are "only" suitable for a Megane 3 Coupe, I wanted to confirm the correct gap in case there was some variation in part numbers/gaps for different vehicles (IE: I've seen stock systems use the same part number for the same "part" with slightly different dimensions). Now I know that is not the case with NGK parts.

Best,
George.