TR2/3/3A TR3 No Start...Again. Help?

[curdy]

Got the parts today and finally had some time to get my hands dirty. Just realized that I overlooked the fact that my coil is screw in and my new wires and cap are push. Any way to make it work with the coil I have or do I have to replace it just based on adaptability?

 

[TR3driver]

I wondered about that, guess I should have spoken up. As a temporary measure, you can use the nut & washer on the carbon core wires. Put the center conductor through the hole and bend it to the side while you stuff the wire and washer into the coil tower, then screw the nut down on top of it. Not a long term fix, but should last a few thousand miles anyway.

Or call around, and see if a local auto parts store has the coil you need in stock. Any place that caters to the vintage VW/dune buggy crowd should have one. Probably not O'Reillys or Autozone, but try all the independent shops.

Or, if you have Amazon Prime, it appears you can get free 2 day shipping on a nice Pertronix coil
https://www.amazon.com/PerTronix-40...d=1462417679&sr=8-5&keywords=ignition+coil+vw

 

[NutmegCT]

I admit - I'm impatient. I'd use the old coil with all the new parts, and see if the problem is solved.

If not solved, then put in a new coil. If problem is solved - then it was the coil!

T.

 

[curdy]

I wondered about that, guess I should have spoken up. As a temporary measure, you can use the nut & washer on the carbon core wires. Put the center conductor through the hole and bend it to the side while you stuff the wire and washer into the coil tower, then screw the nut down on top of it. Not a long term fix, but should last a few thousand miles anyway.

Or call around, and see if a local auto parts store has the coil you need in stock. Any place that caters to the vintage VW/dune buggy crowd should have one. Probably not O'Reillys or Autozone, but try all the independent shops.

Or, if you have Amazon Prime, it appears you can get free 2 day shipping on a nice Pertronix coil
https://www.amazon.com/PerTronix-40...d=1462417679&sr=8-5&keywords=ignition+coil+vw

I keep reading this and just can't quite picture what you're describing. I've searched for threads and pictures and haven't had any luck. Any additional help you can provide to explain or show would be great. How come there isn't an adapter out there for something like this? Seems as thought it wouldn't be that uncommon for someone to want to keep there existing ignition (if it's not the issue of course, which I haven't determined yet.)

 

[curdy]

What's up with the mixed listings for plug gaps? Some say .032 some .025. One's I'm removing are at .032

 

[NutmegCT]

Until Randall steps in, I'll say - don't worry about the plug gap yet. But go buy a new coil. A "generic" 12v ignition coil should run about $20, and will have the plug in connection at the top, not the screw on.

You're only trying to see if the ignition system is what's giving you problems, so a temp coil should be sufficient to do that. You could even just carefully lay the new coil in place on a big towel, then switch wires.

If the engine fires up, you've solved the problem. If not, then it's not likely an ignition problem. (I'm betting it's ignition.)

Tom M.

 

[sp53]

The ignition system is 60 years old and not commonly used in today’s world. This is a simple fix; go to the auto store and show them and they will more than likely give you what you need.

 

[curdy]

Yeah, I decided last night to just replace the coil.

 

[NutmegCT]

Yeah, I decided last night to just replace the coil.

Keep us posted. We've all been through this at one time or another.

 

[martx-5]

There are basically two "generic" coils. One is used to work with a ballast ignition and the other with a non-ballast ignition that the TR3 has...at least if it's original. The non-ballast ignition needs a 3 ohm coil as measured between the two small posts...the primary windings.

More info at the link https://classicmini.weebly.com/choosing-a-coil.html

 

[NutmegCT]

Art - out of curiosity - if he's just trying to trouble shoot his non start problem, couldn't he use any good 12v ignition coil, regardless of resistance? Not permanently - just for a couple of minutes to test his system, then eventually get the correct coil for his setup.

I don't think we know what modifications, including negative vs positive ground, his car has.

Tom M.

 

[martx-5]

Art - out of curiosity - if he's just trying to trouble shoot his non start problem, couldn't he use any good 12v ignition coil, regardless of resistance? Not permanently - just for a couple of minutes to test his system, then eventually get the correct coil for his setup.

I don't think we know what modifications, including negative vs positive ground, his car has.

Tom M.

Yes he could Tom. And positive vs. negative ground would really have no effect on the coil either, although theoretically, the coil can deliver a slightly hotter spark when hooked up correctly. Also, a ballasted coil (1.5 ohm) is designed to start using a full 12 volts in order to deliver more voltage to the plugs and then once running the ballast resistor will drop the voltage going to the coil, so it doesn't burn out.

However, I got the impression when curdy said he was going to "just replace the coil" that he was going to buy a new one, hence the concern about getting the correct one.

 

[NutmegCT]

Thanks Art.

T.

 

[TR3driver]

My experience has been that running a coil that needs a ballast without a ballast will overheat something pretty quick. I once melted the rubbing block in about an hour. So it's fine for a quick test, but I wouldn't go any distance that way.
Of course you could always add a ballast if you want.

Voltage while cranking is only 10-11, not the 13-14 you get while driving.

 

[curdy]

So how do I know which one to get? Can I just get the ballasted one? Not sure if the pic helps or not

 

[NutmegCT]

For your test, you can get either the "external ballast needed" coil, or the "internal ballast" coil. You'll only use it for a few minutes. Probably then just return it to the shop, saying it's the wrong one. In other words, just get the least expensive 12 volt coil.

When you know more about your car's ignition system (does it have an external ballast already in line?), then you'll know which kind of coil to get. Call Moss Motors and talk to a technical advisor; they know what they're doing, and will ask the appropriate questions to guide you on what coil to buy.

Moss Tech: 805-681-3411

Tom M.

 

[martx-5]

So how do I know which one to get? Can I just get the ballasted one? ...

What you want is the NON- ballasted coil. It should measure about 3 ohms across the two small terminal. You could use a ballasted coil (1½ ohms), but then you would also need a ballast resistor to put in series between the ignition and the coil. No sense in complicating the issue, just get one that doesn't require a ballast resistor.

 

[TR3driver]

It's possible someone has added a ballast to your car , but not very likely IMO.

To check, you can either install a jumper from the point terminal to ground,or just turn the engine until the points are closed.
Then turn the key on and check the voltage from the coil hot terminal to ground. With a ballast,you should see 6-8 volts. Without a ballast ,at least 11.5. Anything else probably indicates a bad connection somewhere (could be a bad switch), or a rundown battery.

The unballasted coil is harder to find, because more cars used them (and practically anything after 1972 or so). But they are out there.

 

[curdy]

What you want is the NON- ballasted coil. It should measure about 3 ohms across the two small terminal. You could use a ballasted coil (1½ ohms), but then you would also need a ballast resistor to put in series between the ignition and the coil. No sense in complicating the issue, just get one that doesn't require a ballast resistor.

Art, I apologize as I did not notice the link you provided in an earlier post. That does explain it in a simple manner.

I haven't had much time to dedicate to this over the past couple of days. We are Amazon Prime customers so I think I'll just get the one suggested earlier. Should be here Monday.

So so in the link, it suggest changing spark plug gap if going to a 'sport coil'. I currently set my new ones to .025". Let me know if you all think I should widen the gap based on the coil.

https://www.amazon.com/PerTronix-40...d=1462417679&sr=8-5&keywords=ignition+coil+vw

 

[bnw]

The wider plug gap will force the coil to produce a hotter spark. Most modern coils can handle that. Back in the day, the stock Lucas coil probably couldn't. Keep in mind the HEI GM ignition systems of the 70s and 80s. High energy ignition, .080 plug gaps. Hotter spark, more complete ignition, lower emissions, etc.