10 replies to this topic

[thebullet]

Just about to fit a set of new spark plugs, I have the Lucas coil and can't remember what gap I can increase the spark plugs too?

EDIT: Sorry guys, forgot to add it's the gold sports one!

Cheers.

Edited by thebullet, 09 February 2012 - 08:39 PM.

[dklawson]

If you still have a points ignition system... don't open the plugs up much at all.

The purpose of opening the plug gap up is to develop higher spark voltage and hopefully hotter sparks. Changing the coil type while retaining points has limits that are not much above factory settings. The problem is that with a points ignition system there are limits on how much you can open the plug gap up due to the mechanical charge/discharge timing that is possible. Electronic ignitions don't have that issue and therefore, you can open the plug gap up to as much as 0.035" through trial and error.

[thebullet]

Ok, so what sort of gap should I be looking at?

[thebullet]

Anyone know of a gap I can set them too tomorrow please? :)

[tiger99]

25 thou should get it running tolerably well, if in doubt.

An MPI is officially 0.85mm, which is about 35 thou, and the 1976 manual says 25 thou, 0.65mm. My 1984 City E was 35 thou.

[thebullet]

I have a 998, with a 12g295, points ignition.

Was yours points? or electronic?

Might leave them at 25, I think the ones in my car currently which I am about to change are alot larger than these new ones sitting infront of me.

[thebullet]

I may just keep them at 25 thou. So increasing them just a little bit, what are we talking 28?

[tiger99]

It was points at 35 thou on the City E, but I fitted it with an electronic system anyway. I just don't like having to maintain unnecessary things like points.

[thebullet]

They havn't really had caused me any trouble at all. Hmm I wonder if I should try 35. I really can't decide. 25 or 35. hmm.

[racingbob]

my historic race mini with points and sports coil was 25 - 30 thou gap plugs

[thebullet]

I just left them at 25, doubt I would notice much. Seems alot better, flat spot isn't there much anymore, but the 2 middle plugs came out looking like this... running a bit lean?

Edited by thebullet, 10 February 2012 - 11:22 AM.