Xantia V6 - spark plugs

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Hell Razor5543
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Re: Xantia V6 - spark plugs

Post by Hell Razor5543 »

Ask Mandrake, as he has done some research on this (for his former V6 'Problem Child').
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Hell Razor5543
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Re: Xantia V6 - spark plugs

Post by Hell Razor5543 »

You could also look through his blog for that V6, but be aware, it is 139 pages long!;

http://www.frenchcarforum.co.uk/forum/v ... 14&t=41273" onclick="window.open(this.href);return false;
James
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Re: Xantia V6 - spark plugs

Post by Northern_Mike »

Page 90 is the page you want.

Well, you don't actually, as life's too short, but Simon, on that page, put in new Bosch FR8KDC....

That's all you really need to know isn't it?
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Re: Xantia V6 - spark plugs

Post by Mandrake »

I would stick with the Bosch FR8KDC, that's what worked best for me in the problem child out of three different types that I tried and is what I will be fitting when I do the plugs and wires on the new one.

I had serious trouble with plug fouling when I fitted Bosch FR7DC+. They're a heat range colder (among other differences) and within 1000 miles the insulators on all 6 were carbon fouled to the point where at least two cylinders were misfiring with the spark tracking across the insulator, and I'm sure the other plugs weren't far behind.

If you did only long trips you might get away with the colder plugs not fouling but if you do short trips they'll foul quickly. I swapped in some FR8KDC and the fouling went away completely - I checked those plugs twice, once at about 1000 miles and again after another 1000 and both times the insulators were spotlessly clean and white with no problems and no spark plug related misfires...

Interestingly the very early spec sheets for the engine say FR7KDC (a colder plug) but all the later literature says FR8KDC - that suggests to me that they revised the spark plug spec for a hotter plug after customers experienced fouling issues.

Other differences between the two is that the FR8KDC is dual electrode with a resistor core while the FR7DC+ is a single electrode with no resistor core.

On a waste spark system like this you get twice as many sparks as normal and therefore twice the spark plug erosion rate - the reason why dual electrode plugs are specified. If you fit single electrode plugs they won't last very long unless they're expensive rare metal electrodes.

The car came fitted with single electrode NGK plugs when I bought it - I don't remember the exact type, it will be in my thread somewhere. They were "OK" but I don't think they were as good as the Bosch FR8KDC.

I think its one of those cases where the OEM spec part is pretty much optimal and straying too far is not a good idea. IMO if you do want to try different brand plugs the most important thing is to stick to the same heat range, which can be difficult when each manufacturer uses their own unique heat range numbering system that doesn't always have a direct correlation with another brand!

For example the NGK heat range numbering system is back to front to Bosch and the conversion charts don't always agree on what is equivalent...

The Bosch FR8KDC come pre-gapped to the correct gap, and you can't gap a dual electrode plug anyway. So just buy and fit...
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
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Re: Xantia V6 - spark plugs

Post by Mandrake »

Here is a direct link to the spark plug comparison post in my thread, with photos:

http://www.frenchcarforum.co.uk/forum/v ... 40#p382440" onclick="window.open(this.href);return false;
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1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
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Re: Xantia V6 - spark plugs

Post by Stempy »

I used to use these in mine

http://www.halfords.com/motoring/car-pa ... ug-x4#tab2" onclick="window.open(this.href);return false;

It ran a treat and never had any ignition issues. I use the same type in the C5 though they have a longer thread for the later engine.
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Re: Xantia V6 - spark plugs

Post by KP »

The only time you want to stray from the OE type fitments is with LPG where you want a hotter running plug, or when you up the boost on a petrol vehicle the same needs to be done :)
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Post by addo »

I always check the gaps, if wrong it's well possible the plug has been dropped.
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Re: Xantia V6 - spark plugs

Post by Mandrake »

KP wrote:The only time you want to stray from the OE type fitments is with LPG where you want a hotter running plug, or when you up the boost on a petrol vehicle the same needs to be done :)
Are you sure you have this the right way around Will ?

All of the recommendations I've seen for LPG say that it might be necessary to use a spark plug one heat range colder for LPG than Petrol, because LPG burns hotter. For example:

http://www.jktowers.fsnet.co.uk/motorho ... kplugs.htm" onclick="window.open(this.href);return false;

In fact the colder Bosch FR7DC+ was recommended for LPG use in the ES9J4...
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
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Re: Xantia V6 - spark plugs

Post by Northern_Mike »

KP wrote:The only time you want to stray from the OE type fitments is with LPG where you want a hotter running plug, or when you up the boost on a petrol vehicle the same needs to be done :)
You've got that the wrong way round. In the Saab turbos I tuned, the more boost you used, the colder the plug you needed to run to avoid knocking. You want to get heat out of the chamber, not keep it in..
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