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Spark Plugs

This has spun out of a club bulletin board discussion, seems an easy question but I have a few conflicting answers - Badger, your advice seems good but contradicts the literature so I wanted to throw this out to a.f.l to see what everyone thinks.

Simple question.

Land Rover Discovery 1997 V8 Auto 3.9 not LPG. What spark plugs should it have?.

When I bought it it had champion NY11C

To replace them I bought 8 more but then, for reasons I won't go into put in NKG BP5ES instead.

The car has issues anyway - running far too rich (sooty plugs) and returning 11mpg driven gently down the motorway but those I am dealing with.

So

What plugs should it have?

How important is the correct torque for the plugs or is doing it by feel OK? NKG website says its vital.

And also - when I changed the leads and dizzy cap this weekend it wouldnt start at all - traced it to a bad connection at the coil, corroded HT lead 'socket'. Its now going again but it worth putting in a new coil too - will it help pep it up.

Performance wise, turning onto a slight hill (1 in 20 ish) from a 10mph turn it wont go into 3rd gear at 30mph - stays in second all the way up. I don't think that's right.

Thoughts.

Badger - feel free to reitterate your advice.

Reply to
John Page
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NGK BPR6ES, Chumpion RN9YCC, or platinum equivalent, or irridium if you feel flush!

Assuming it's the 9.35:1 compression ratio engine, N11Y's are too hot a plug. Perfect for the 8.13:1 "soft" engines though. landrover fitted hotter plugs to bring the emissions down ever so slightly, BUT there are too many issues with 3.9 and larger engines having cracked blocks behind the liners and liner dropping, some say caused by high combustion temp due to leaner mixtures for economy, which is why I never fit hotter plugs than N9/BPR6 - might not make an awful lot of difference, but it's piece of mind, IYSWIM.

Still slightly hot, but not as bad as N11's.

Done the coolant temp sensor yet, John?

It would! Tight enough not to work loose, but not too tight that you risk stripping the ally thread out of the head. Most people do it by feel, but the feel is usually based on probably years of experience.

Won't necessarily pep it up, but it eliminates another potential problem.

Kickdown cable adjustment too tight??

Ta, I did. :-)

Badger.

Reply to
Badger

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