[308] Spark Plugs

[Not_An_Abba_Fan]

Well, after years of assumptions, we thought we would actually physically check the engine number of the missus' burnout car after a cam package recently came up for sale. She was told it was a VT 5.0L. After actually looking at the engine number, it has a VT prefix so it is actually a VB-VK 308 with injected heads.

My question is, what are the best plugs to use for it, considering it is a burnout car. I have just been using VT plugs, but since it is not actually a VT engine, does anybody have a recommendation for plugs that would be better for it?

I don't know the internals, but the way it runs suggests a mild cam. I will have to do a compression test on it to see what sort of compression it has, but it's pretty good. When it was on the road it was fast. She took it down the strip once, just after she got it, and it ran a low 13 I think.

 

[VR38]

I would be using what ever plugs suit your ignition (dizzy/coil) so if you have a VC (blue motor) system then use blue motor plugs, same for red/black carby, or if you have a VT system then use VT plugs.

Hope that helps.

 

[Not_An_Abba_Fan]

Don't know what colour the motor was, it's been stripped and painted a horrible grey. Would the serial number tell us what series it is?

And no idea what ignition system it has.

 

[VR38]

Sorry for the confusion.
Forget what colour motor you have.

You need to establish what coil and what dizzy you have.

 

[Not_An_Abba_Fan]

As in whether or not it's an HEI distributor?

 

[VR38]

Yes and more importantly what coil you have, each system uses it's own coil that works with a particular gap range, as the dizzy's main job is to fire the coil and works within a particular ohm range to be efficient.

If you can't find the part number of the coil or don't know what car it originally was meant for then you will need an ohm meter to test the high and low side resistance to determine whether it is a HEC (High Energy Ignition system [carby]), MEC (medium Energy Ignition [PFI]) or some other (hopefully not) systems coil.

At the end of the day a gap of around 1mm should see you there unless you are experiencing problems due to gap size.

Another thing to consider is what heads you have, unrelated to gap or ignition system, as some plugs I have found have a long reach which will protrude the plug too far onto the combustion chamber (exposing the end threads to the combustion chamber) so whatever plugs you end up running you have to check the reach is equal to the plugs reach that was originally specified for those heads.
Hope that helps.

 

[Not_An_Abba_Fan]

Bit more complicated than going into Auto One and asking for spark plugs lol.

As I said, we have been running VT plugs, but since it isn't a VT engine, I would rather find the correct plugs and use those.

 

[VR38]

No worries, good luck, just don't go confusing the matter with block colour or prefix, all the bottom ends are the same and have no bearing on what plugs or for that matter, what coil or dizzy you use.

 

[Immortality]

I bet you all Holden V8 engines have all used the same basic spark plug but only a variation in plug gap to suit the type of ignition system used. If the VT plugs work then keep using them, if they are been used in a burnout weapon and the spark isn't breaking down when it gets hot etc then the plugs are working good.

I think from memory the holden V8's (blue/black) used BPR5FS15 (1.5mm gap), VT uses BPR6EF1 (1mm gap and the same plug used since VN). the number (5 and 6) refers to the heat range, the smaller the number the hotter the plug (for NGK plugs, champion plugs are the opposite), so in your case, using the VT plug is a slightly cooler plug with a smaller gap which suits higher CR's and cylinder compression etc.

Google is your friend http://www.ngkspark.co.nz/spark-plu...N&Model=Commodore+VT&Year=09/97+-+10/005.0LV8

Cheers

 

[ari666]

put some 5/15's in it which is what 308's run normally and check that they burn ok. CR determins if you need colder or hotter.