GTV6 Spark Plugs

[Fylnn]

A question about spark plugs.  I am running NGK B7ES set at 0.8mm which I believe is the correct plug to use?  Is it?

Anyway it has had a few distributor and fuel injection issues (Haltech).  It now runs a Hall effect from a 75 and that has improved it somewhat.  But every time it went in the plugs got changed.  I have had it out on a few test days and it ran hard and well.  lit is a rally car.  Yet tonight had it out and after switching off and restarting it had a bit of a fluff and miss for a while and then seemed to clear.

Looking on a few forums, I get the sense that plugs can and do foul in these things.  Is there any conventional wisdom on what people use in track type 2.5 litre V6 engines.  Since next event is this weekend coming, working on spare parts and solutions in case it starts to foul plugs. 

[Fylnn]

Well I suppose the short question should be, are NGK B7ES the correct plug? 

How prone to fouling plugs are Alfa V6's? 

[colcol]

From the 33 point of view, i also use NGK B7ES, as they seem to foul less than the NGK B6ES that are recomended for my car, it used to run fine on the B6ES in the leaded petrol days, but they foul  once in a while on the unleaded petrol, the B7ES plugs run a little hotter and burn all the rubbish off, i set the gap at about .028 thou, which is about 0,7 mm, you will have to try and see which suits your motor and driving style, Colin.

[alanm]

HI Flynn,

The V6 is quite prone to plug fouling.

On the recommendation of specialist (and club sponsor) I moved from the plug I was using to a hotter one.
In my experience, if you start the car cold and let it run for only a few seconds before switching it off, say moving it out of the garage, washing it and putting it back in, a plug might foul.

The specialist I discussed the problem with told me that it often happens in his workshop, moving the cars on and off hoists etc. He lets them run a few minutes before switching them off.

They have always done this, and always will probably, but the hotter plug should help.

I keep the factory plug remover tool (double jointed) and spare plugs in the boot!

Cheers,
Alan

[alanm]

Oh, forgot to mention...
The explanation for this is the relatively 'dumb' engine management system delivers fuel to all cylinders regardless of whether they are firing or not.
I am not very clued up on this sort of thing but I think the Jetronic system (?) does this but the Motronic (?) in my 75 sends fuel only to the cylinder that is firing.
Also, I wonder whether the design of the head, with the deep wells for the plugs, results in a little oil migrating down into the plug thread (even with new head and valve cover gaskets).

Cheers,
Alan

[Fylnn]

Further update on this.  Went to pull it out of the shed the other night and it barely started then died.  Thinking as I have been in this thread, immediately changed the plugs.  The car started again but was night running well.  I was taking it across town to scrutineering.  It died again on the way.  So sat there questioning why I bought a classic Alfa as sometimes you do.  Car then restarted when I twisted the key and ran beautifully all the way across town.  On way home went just fine as well.

This erratic behaviour was by now wearing pretty thin.  But was becoming suspicious that the Haltech was not getting the right signal sometime.  'Rebooting' the car periodically is not an attractive prospect.  So later that evening was showing someone where the computer gets its power from (straight from the battery +ve terminal) and when I poked at the wire it moved.  The whole +ve battery lead was flopping around loose.  Obviously sitting around, the connection oxidised or corroded or something and caused a voltage drop. 

Anyway with a  tightened +ve lead we now start and run.  The answer is not always on a lap top.  It is easy to overlook the basics. 

[Duk]

Anyway with a  tightened +ve lead we now start and run.  The answer is not always on a lap top.  It is easy to overlook the basics.

With data logging, if you'd been looking for it (and knowing what I know these days, sh!tty supply voltage is definitely something to keep an eye on!), it would have shown up with data logging! Assuming, of course, that the Haltech logs battery voltage. 

[shane wescott]

I run the same plugs and always have spars in the boot (cheaper to buy them by the box :-)  )

My method for picking a fouled plug is let the car cool down totally, run it for a short time and then work out by touch which exhaust pipe is cold.

Changing the plug fixes it for me.

My reading of NGK stuff would mean that a hotter plug qould be a B6ES not the 7 ??

Catch ya

Shane