Euro 02 cam affects spark plug gap?

[Ziggy]

I have replaced my 08 cam with the "Euro" 02 type cam. After this the engine idled badly, and hesitated on both lower and higher revs. It felt like it was an ignition problem, but the whole ignition was new and up to the point when the cams were exchanged, the engine ran perfectly. It took a long time to find the culprit.

I have been using a spark plug gap of about 1,1-1,2 mm (0,045). This worked perfectly with a powerful ignition. For some reason, this doesn't work in combination with the new cam. I regapped the sparkplugs at 0,8mm (0,032) and this made a world of difference.

Why would the new cam have any effect on the spark plug gap? It doesn't seem logical to me. The engine still misfires every now and then in D, I think the gap may need to be even smaller.

[Shvegel]

By replacing the cam you effectivly increased cylinder pressure. The higher the pressure the harder it is to get a spark across a given gap.

Point condition, gap and dwell all effect the firing voltage as well as the secondary ignition components(coil,cap wires plugs).

It does seem odd that you can't fire a .45 gap. If you don't have electronic ignition(I have a pertronix that I love) You might want to look into it. Also spark plug brand also can have a great effect on the performance of the plug.