Spark plugs again

[Johan G]

I'm planning to replace the spark plugs on my S3C (2.9 litre engine). I would like to fit NGK plugs, but I don't know the exact type. So I thought I'd better ask you guys.

Cheers
Johan

[Batty S4C]

www.tvrcc-south-wales.co.uk/Sparts.asp

try this.
I do have the NGK serial somewhere, will find it out.....

[Johan G]

Oh, sorry, I have looked at that list before. Must have missed the NGK plug stated there. Thanks.
It seems like they recommend the type stated there for sprinting. Maybe they will be too cold for more ordinary use? Has anyone tried them?

Johan

[Peter M]

The plugs quoted on the South-Wales site, NGK BCPR6ES are standard parts you can buy anywhere. In fact they are the standard parts that I have used for years in my Fiesta Mk1 XR2 with the Kent X-flow engine. I have never had a problem with them, and only fit these as I know they work. The car is used as the daily commute/run about, not raced.

If they are the right part, then that is what I will be fitting when I change the plugs on my S2.

[Johan G]

Thanks Peter!

After doing some research and checking what type of Bosch plugs that are currently fitted to my S3C, I have decided to go for plugs with tapered seat.

Some research yesterday resulted in the following list of spark plugs with tapered seat:
Bosch HR9DCX (currently on my S3C)
NGK BPR6EFS (like BCPR6ES but with tapered seat instead of gasket)
Motorcraft AGRF32C1
NGK TR5 (like BPR6EFS but with V-grooved center electrode)

Sources:
[url]www.ngk.co.uk[/url]
[url]www.ngk.com[/url]
[url]www.ngk.se[/url] (in swedish)
[url]www.sparkplugs.com[/url]

I still feel a bit unsure about choosing plugs with tapered seat, but since that type has worked fine on my car before I think I'll stick to them. It seems like they can be a bit difficult to remove though. The Bosch plug I removed yesterday almost felt stuck to begin with, but finally came loose. A local Ford dealer recommended to put some copper paste on the threads when mounting the spark plug to have less trouble removing it. I hope this may be of some help.

Cheers
Johan

[tvrgit]

Hang on.

Your cylinder head is machined to either accept taper seat plugs or not. AFAIK they are not interchangeable.

If you put a taper plug into a non-taper head it will damage the plug (or the head) and won't seal properly.

A gasket plug won't seal properly in a taper seat head.

[Johan G]

Yes, that is exactly what I have found out too. So as spark plugs with tapered seats have been used previously on my car, I will continue to use that type.

Edited to say:
Is there any other way to know what type of cylinder head you have on your car? Like some kind of marking or number? Does anyone know?

Johan



>> Edited by Johan G on Wednesday 14th April 13:22

[WildfireS3]

Just got a set of NGK BCPR6ES for mine. That's what was quoted for the engine a 2.9 V6 1991. Not put them in yet. Will do it tomorrow, should complememnt the magnecore leads nicely.

[Johan G]

Maybe this is not a big issue at all? Seems like both types will work.
I replaced spark plugs (except the front right one which will require a modified socket), rotor and distributor cap last night. And now she runs like a dream! And they say the weather will be nice here this weekend. Can't wait for some driving in the sun!

[tvrgit]

Johan G said:

Maybe this is not a big issue at all? Seems like both types will work.

Both types will work, true.

Only the right type will work properly, and without damage to either the head or the plugs.

You can tell which type you need by looking at the spark plug hole. It's obvious if it has a taper seat (a chamfer round the edge of the hole) or not.

>> Edited by tvrgit on Thursday 15th April 08:36

[Johan G]

Allright, allright, I'll take a closer look when I replace the last spark plug. I'm not an expert so to me it will probably still not be obvious. I'll see if I can get a close-up picture taken.

Johan

[Johan G]

Here is a picture of the front right spark plug hole of my S3C. To me it seems to be machined for tapered plugs where the arrow points in the picture.


Johan

[tvrgit]

looks like a taper to me too, right enough, from the photo...

sorry Johan I don't think you were confused - but there was talk in earlier posts here about taper and gasket plugs being interchangeable, and they're not, I just wanted to help make that clear...

[Johan G]

I understand that completely. I wanted to be sure about what was right for my car, since it is the first time I'm replacing the plugs. Thanks for making me look into it really thoroughly.

Cheers,
Johan

[shauno]

I put new ngk plugs and a new cheap copy coil in my 2.9 s1 and had all sorts of problems . So i went to gk ford and got new plugs part num 063206 ,and new leads part num f5030306 and it ran spot on untill it burnt out the cheap coil . which i replaced with a ford unit and every thing was coming up roses untill i blew a head gasket. oh well s---t happens

[WildfireS3]

Just put the NGKs in, gasket plugs that came out and went back in. All seems fine.