Coils !!!!!!

Good evening to you all, coils, what about these things ? By the way I am on about old cars, do they have to match the vehicle !! is there any difference with them ?

What is a reliable way of testing the output of them how can you tell if it is going to give you a good old fat spark :) to the plugs..

Rich

-- To reply remove " spam "

Two basic types, ballasted and un-ballasted. Try to stick to the same type of coil as the system requires. To identify the type of system, measure the voltage at the + terminal (on -ve earth cars) with the ignition on. If it is 6-9V then you have a ballasted system, 12V is a non-ballasted system.

I believe that a 6-cylinder coil differs from a 4-cylinder coil (possibly needing to recharge in a shorter time), because I have never yet managed to get a 4-cylinder coil to work with any of my V6's.

You can identify coild types with an ohmeter,

ballasted typically 1.2 ohms, un-ballasted 2.4 ohms.

But I cannot find a measurable difference between 4 and 6 cylinder coils.

There used to be a tester with a variable air gap which you closed down while flicking the points, until a visible spark occurred. However, coils will often give a spark in a lightly-loaded condition but fail to work properly on the engine.

I now have a basic test - if it will start the engine from cold it'll be fine, otherwise I junk it and fit a new one.

Some of the more up-to-date testmeters might have a better way of checking, but they tend to cost 5 times as much as a new coil would in the first place.

Adrian_S

I once saw a coil with a bakelite top on a glass bottle, and through the glass you could see it was filled with oil. It was an early 1950s car, but I can't remember which.

Never seen one since, though.

Jim

The traditional aluminium-can-with-bakelite-end type of coil is in 99% of cases filled with oil both to cool and to insulate the windings. I once fixed an "oil leak" on a friend's car by replacing the coil - the throttle cable had been rubbing against the coil can and had worn through it letting the oil run out!

One make like that was the "Runbaken Oil Filled Coil" available just after the war - one was fitted to my late brothers MGTC

There is one for sale for £25 at:

And the oils are carconogenic or however you spell it. So be very careful.

Andy

This mail has been checked for smelling pisstakes by a speelchecker

It was somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Adrian_S saying something like:

I've generally found that a free-air spark with a tinge of orange is a sign of a failing coil.