Coils and ignition help please

coils and ignition help please

Posted by tony_labbett at July 03. 2011

Help, After buying an 850 in 5 boxes and becoming NOC shop, RGM and Andover norton's best mate i'm at the wiring stage, the old alternator came without wires so that's been replaced with a 3 phase lucas alternator, a podronic 3 phase unit and a boyer mark 3 unit i had on the shelf. It seems a daft question but do I use 12v coils or 6v coils if so do they go through the ballast resisitor. I've looked at various sites and if the boyer is fitted they keep the 6v coils, have i answered my own question or would 12v coils be better.

Another daft question is the ignition switch, where is it secured to on the frame.

Re: Coils and ignition help please

Posted by jack_blakemore at July 05. 2011

Tony,

I've basically just done the same myself. It depends on the ignition type that you are using rather than the alternator output, as I understand it. I retained 6v coils, and as I have electronic ignition I do not use a ballast resistor across the coils.

I was advised that 12v coils would be a mistake with electronic ignition, and that the ballast resistor can go.

BTW - I don't know what type of 850 yours is (1,2 or 3), but if it has the warning light control unit and you have fitted a 3 phase stator (3 x 4v windings), it is likely that your ignition light will only go out over 2.5 thousand rev's, as the warning light unit can only accommodate 2 coils taps for it to sense - theoretically 8 volts. Unless of course I'm being a complete chump! However mine did do this as I expected so I'm getting shut of it and putting a rather clever LED device across the battery! Still shows charging (red,yellow,green) etc., but doesn't require a splice from the stator feeds.

It is also worth taking the opportunity to replace the 2M capacitor.

I used one of these:

Specifications

	Capacitance Value	4700μF
	Construction	Can
	Equivalent Series Resistance	0.036Ω
	Leakage Current	6000μA
	Maximum Operating Temperature	85°C
	Minimum Operating Temperature	-40°C
	Mounting	Screw Terminal
	Product Diameter	36mm
	Product Height	52mm
	Ripple Current	6700mA
	Tolerance	20%
	Type	Electrolytic
	Voltage	63Vdc

Which may be found at:

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=3819087P&x=31&y=14

Better spec than the original, a bit cheaper and screw in terminals are far more preferable in my opinion.

Hope this helps

Jack