Replacement coil

[jstoezel]

I was at the local Canadian Tire trying to get a replacement coil. They don't have the blue 12V coil from Bosch (that's the one I currently have), but their system lists a replacement part for which I've never heard of the brand (could be DRW or BRW can't remember).

Price seems ok, should I go for it or do I really need the blue coils?

Jean

[Dietmar]

Jean:

Canadian Tire???? Are they still around?

CiP1 ( Canada ) lists several blue coils, bit pricey compared to the US but by the time you pay duty, it might be about the same.

Dietmar

[tiagosantos]

Cip has the one you need, if you don't need it NOW.

Dietmar - Canadian Tire is huge, they aren't going anywhere.. Except they don't really sell that many tires anymore, it's just a big store, kinda like Sears..

[jstoezel]

Hi Dietmar:

Canadian Tire is stronger than ever I would say it's even an institution here.

With shipping it looks like a blue coil from CIP Canada will be $75 if I only order this (I've ordered everything I needed last week - except this coil). Do I really need the blue coil?

Also how do I test my current coil? I've measured 2.9 ohms at the primary, and about 9k ohms at the secondary. When I connect it to the rest of the circuit (- to the distributor, + to +12V) I've measure the battery gets shorted (I don't really short the battery, it's out of the circuit and a DVM measures about 3ohms in between the + and the ground). Doesn't seem right to have such a small resistance, looks like it's from the primary of the coil.



Jean

Jean:

Canadian Tire???? Are they still around?

CiP1 ( Canada ) lists several blue coils, bit pricey compared to the US but by the time you pay duty, it might be about the same.

Dietmar

[FV80]

... the battery gets shorted...

Jean,
Your points (assuming you have them) are probably closed. Rotate the engine to open the points and check again. Although POSSIBLE, it is highly UNlikely that your coil is bad.
Steve, FV80

[SR Racing]

Steve is right, it probably is not your coil, but possible. The low resistance 2-3 ohms is fine. USUALLY when a coil goes bad it is the seconday windings that short and you normally can't tell that with a ohmeter. They will short (arc across internally) with the high voltage. About the only good way to diagnose one is swapping it out.

[jstoezel]

Thanks for the reply. In all honesty I was thinking that the points could have been left closed (since what I was measuring from the battery -about 3 ohms- looked like the primary shorted to ground), but at the same time I thought there must (should) be some way of preventing this as you can't control where your engine shuts down and whether the points are left open or closed.

I don't have wheels on the car just yet, and no battery to turn the engine either so I can't move the engine and test again. I have minimum clearance between the poulie and the firewall too which doesn't help.

It seems like this is a lot of current you could draw if you ever stopped the engine and the points would be left closed... I guess it's best never to let the ignition on if the engine is not running.

[tiagosantos]

Yup, never a good idea to leave the ignition on without the engine running for exactly that reason!

[cendiv37]

Jean,

If you have drums on the rear, you should be able to turn the engine over enough to open or close the points. Adjust one drum up tight and then put it into 4th and turn the other drum to rotate the engine (easier yet if you install a wheel/tire to get more leverage).

Or with the ignition off you could also put a piece of clean paper between the points to make sure they are not touching. Just make sure you "remove it before flight"...

[Edward Schubert]

Take the spark plugs out...then even your wife can turn the motor over for you!

[jstoezel]

Tonight I tried to start the engine but I can't seem to get it to fire. There is gas for sure, I think it has something to do with the ignition.

I've measured 12V at the coil on connection 15 (+). Connection 1 seems to stay close to 0V even when I crank the engine. I've opened the distributor and I can see the points opening and closing. I was told I may be able to see tiny sparks when the points close but I haven't seen anything like that.

The engine is straight from the shop, I haven't touched anything. The only difference with the way it ran at the shop is the coil (I didn't send it with the engine).

I get from previous posts that the coil is most likely ok, I've ordered a spare though. What should I check? How do I check that the points and the cylinder (?) attached to the distributor are good?

Jean

[SR Racing]

With the ignition on you should have 12V on the (+) (15) post. On the (-) (1) side you will see it go from near 0 to 12V as you crank the engine. It is best to use a test lamp when doing this, since a meter won't react fast enough. One side of your test lamp should be clipped to ground.

The way the ignition works is the coil always has 12V on one side (15) and the other side will have ground applied to it through the points. When the points are closed the coil has full current flow and will build a magnetic field. When the points open, this feild collapses into the secondary wires of the coil and create a short HV burst at the top spark connection of the coil. This HV burst is transferred to the plugs though the distributor and rotor.

If you have voltage pulsing across the two small connectors at the coil and you are not getting spark, your coil is defective.

If as you say you always have near 0 volts (on (1) when you crank the engine... 1. Your points are not opening and closing, or 2. your coil is open.

The only time I have seen a coil do this is when the ignition switch was left on for a long period of time. This action will either burn the points and/or wire, OR heat the coil until it opens (or shorts).

[jstoezel]

Well I may have damaged either the coil or the points as you suggested. As explained before I didn't realize the battery was more or less shorted (via the primary of the coil) when the points are closed.

12V is there on the + of the coil. When I crank the engine with a lamp connected between the - and the ground the lamp does not turn on.

If the coil was open, I wouldn't be able to measure a resistance on the primary... I can see about 3 ohms on the primary, almost 10k on the secondary.
I guess then the points must be defective...

With the ignition on you should have 12V on the (+) (15) post. On the (-) (1) side you will see it go from near 0 to 12V as you crank the engine. It is best to use a test lamp when doing this, since a meter won't react fast enough. One side of your test lamp should be clipped to ground.

The way the ignition works is the coil always has 12V on one side (15) and the other side will have ground applied to it through the points. When the points are closed the coil has full current flow and will build a magnetic field. When the points open, this feild collapses into the secondary wires of the coil and create a short HV burst at the top spark connection of the coil. This HV burst is transferred to the plugs though the distributor and rotor.

If you have voltage pulsing across the two small connectors at the coil and you are not getting spark, your coil is defective.

If as you say you always have near 0 volts (on (1) when you crank the engine... 1. Your points are not opening and closing, or 2. your coil is open.

The only time I have seen a coil do this is when the ignition switch was left on for a long period of time. This action will either burn the points and/or wire, OR heat the coil until it opens (or shorts).

[SR Racing]

12V is there on the + of the coil. When I crank the engine with a lamp connected between the - and the ground the lamp does not turn on.

This would indicate the the points are closed all the time. (or there is a short somewhere) When the points open the lamp SHOULD light since it is connected between ground and the coil. (It would be in series with coil and 12V.)

If the coil was open, I wouldn't be able to measure a resistance on the primary... I can see about 3 ohms on the primary, almost 10k on the secondary.

Correct.

I guess then the points must be defective.

Or CLOSED all the time,... or a short. To verify this you could do the following: DISCONNECT the points from the coil. Connect your ohmmeter to ground and the wire from the points. When you crank the engine, this resistance will go back and forth between infinity and zero ohms. If it doesn't, your point circuit is somehow shorted or adjusted inproperly.

[FV80]

Or ... as mentioned above - slip a business card or similar in between the points gap to assure no short there and check again. I have seen the connector to the condenser short out between the terminal and the case - which shorts out the points and holds the points end of the coil at ground. You COULD also have a shorted condenser - which can easily be tested by removing it. The car should run without the condenser - the condenser is just there to keep the points from wearing very quickly.
HOWEVER, if you pull the points wire off the coil, put 12v on the + side of the coil and the points side of the coil still says ZERO with the voltmeter - *then* you can be pretty sure you have a bad coil .

Steve, FV80

[jstoezel]

Hi, thanks for the tips.

Too bad I didn't read this in time. I replaced the points yesterday and discarded them. The black/white wire was burnt, there could have been other damage I didn't see. These are excellent tips for me to experiment the next time I invert the wiring.

I now use different connectors for the wiring. The + side of the coil uses a loop type crimped connector that has to be screwed on the coil. The points side requires one of these automotive flat slide-in connectors... This is the stock setup I guess. From now on inverting the wiring would be like trying to fit a square into a round opening.

The car fired up right away with the new points. I borrowed a dwell meter - what a pain to set, I ended up just setting the gap to 15/1000 as suggested elsewhere. Just for this I might just switch to a Pertronix... Do you have to set the dwell with a Pertronix? Apart from the price, is there a real difference to be found in a FV engine between the Ignitor I and II?


Jean

[SR Racing]

No setting of the dwell with a Pertronix. On a Vee the Pertronix I's are fine/ Unless you are going to spin faser than 9000 RPM. Then use the Pertronix 2.