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Re: Stumble, hard start, and backfire...
Posted: Sat Aug 25, 2012 9:47 am
by Roy Gavin
The B44 is a 1970 model, runs a 12 volt 2 wire Lucas rotating magnet alternator, and the OEM zenner? diode and rectifier have been replaced by a single Typhanium? unit. Coil is non stock too.
Is there any relationship between the resistance in the coil and the capacitor size?
Re: Stumble, hard start, and backfire...
Posted: Sat Aug 25, 2012 2:59 pm
by Jean
Yes. But unless you have some weird coil, the normal capacitor range of values as stated earlier ought to work fine.
It has to do with induction, back EMF and the ability of the capacitor to charge and discharge.
A very low coil resistance will allow a high current to flow in the primary...so you'd need a larger capacitor to provide points arc protection...The normal Bosch 6v coils are 3 ohms each and they are wired in series, so the total resistance is 12 ohms. Bosch also said the "normal" capacitor value is 0.3 to 0.4mf, so you can get the idea of the relationship. Note there is a TIME factor in the capacitor-coil tank circuit too, so it's not a direct relationship by any means.
Now, where did I put my EE301 textbook?