Plugs and leads

I am assured by a reputable trade supplier that Bosch Super plus yttrium WR9D+ spark plugs are correct for my 2000 4.0 Range Rover. The web site carsparkplugs.com also throws these up amongst others for the "99-02 Range Rover 2", but their cross reference to the Champion RC11PYPB4 (type shown in owners manual) is a Denso KJ16CRL11 with a gap of

1.1mm. The recommended gap in the owners manual is 0.95-1.05mm. The Bosch ones are 0.8mm! Why this difference in spec? Is this a deliberate ploy to confuse the consumer? Should I stick rigidly to the Champion RC11PYPB4?

I have a drop in power and rough running under 2000rpm. I have replaced the leads and the problem is improved but still not as it should be so I suspect plugs.

Any advice on the plugs to use (or not to use) on this engine appreciated.

David.

Reply to
David Haggas
Loading thread data ...

The 4 on the end of the Champion part number refers to a gap of 0.040" which when deling with spark plugs is generally metricated as 1.1mm. The only plug that seems wrong is the Bosch, although my chart shows it as having a 1.1mm gap.

Reply to
EMB

On the side of the Bosch box for each plug it shows a diagram showing 0.8mm which caught my attention. Although the retailer put my registration number into his system should I trust it to be correct? There seems to be a difference between the 94-98 RR and the 99-02 for both plugs and leads but he said mine showed up correctly as 2000 model year. If the Champion is

1.1mm that falls outside the 0.95-1.05 in the manual yet RC11PYPB4 is the OEM type!
Reply to
David Haggas

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.