Which Coil

[RobSun]

My Dolomite 1300 just like this time last year is not playing nicely.

Again it gets a bit rough when its warmed up splutters a bit on accelerating and if I pull the choke out its ok for a bit. So fuel. All looks ok, float chambers full, filter clean, did the rev and block the air off to try and unblock the jet but symptoms still persisted so thinking a carb strip down on the cards. Eventually engine stopped and wouldn't start. No spark and new ballasted coil and resister done 700 miles is warm. let it cool down a bit and tried again several times to fire it up. It started again after a short while but there was by then the smell of petrol suggesting it was flooding so the fuel looks to be getting through. Then after a short time every so often the engine hesitated and started sputtering again. Started raining went in.

Tried again and it did everything again as before, runs great gets to temp, runs ok for another 20mins or so starts spluttering and cuts out. Checked everything and all as before so I put the timing strobe on and it starts ok, runs for a while and stops. Will not re start and no spark, the timing light is not flashing. Left it to cool a little and it fired up ok, and ticked over ok but with a missed beat every few seconds which shows up on the strobe, so I suspect this new ballasted coil is failing.

I am proposing to go non ballasted and looking at the Lucas 12v 105 gold sports coil. The car has electronic ignition and I found on line a Lucas 12v coil for electronic ignition only. Would this be the better one to go for or just stick with the 105? Also read that with 12v coil and electronic ignition wider spark gaps are recommended for better performance and economy.

I accept it could be the carb but this was refurbed around 1500 miles ago and red jetted and last year was fuelling was seriously considered but proved to be the coil causing virtually the same problems. I want to try to nail this asap as the warrantee on the pretty expensive coil runs out in 2 weeks and if it is the coil want to get my money back.

Thoughts and advice please.

[Galileo]

Have you discounted your electronic ignition to be a contender? Could be worth putting a multimeter on the coil and checking for a flick of the needle as you crank the engine over when it next dies.

If you go unballasted with electronic ignition and a high output coil you could open the spark plugs up a bit, but I doubt you would see much benefit on a 1300.

Fancy a bit of light reading there's a paper on electrode quantities and gaps!

[AlanH]

What sort of ignition have you got? They can be sensitive to the coil resistance which is why I think that it is a good idea to use a non-ballasted.

My first thought is to refit the points and see what happens.

Other than that why not try another coil, There must be someone near you who has one (you don't say where you are).

[GTS290N]

I've seen similar problems with dodgy coils - but I've also had an identical problem with a faulty electronic ignition. The kit only failed when the car was truly warm!
I use one of these:
http://www.accuspark.co.uk/coils.html
Others swear by Bosch, or second hand Nissan colis from the scrappies.
With electronic ignition I would remove the ballast wire and feed 12v straight to a12v coil -after you've found the culprit.

[RobSun]

The ignition fitted is a luminition with their recommended mega spark 3 coil for the unit. This came with its own resistor. When running the alternator is putting out 14.2 v and at the positive pole on the coil after the resistor the voltage reading is over 10 v. As the coil should run at 6v I wondered if this was the cause of the issues and why I was going to go down the 12v coil route.

The coil fitted when i got the car was a correct spec Rimmers ballasted coil. The feed wire should be ballasted in the loom but I found last year when I was having similar issues that this feed wasn't. It pushes out exactly the same voltage as the new feed to the new coil and ignition and this killed the old coil. I suspect that the garage that fitted the electronic ign for me got the same readings and assumed it was a 12v coil. After I fitted the luminition coil everything ran with no issues until bringing it out of winter hibernation when its started again.

[Jon Tilson]

You may find this of assistance....

https://dollywiki.co.uk/wiki/Ignition_b ... ss_removal

I got fed up of typing the same stuff over again...

If you have a Lucas gold DLB 105 coil this is a NON BALLASTED type, which should run at full volts all the time. The Ballasted
gold equivalent is the DLB110.

The numbers are confusing because there are Unipart 110 coils about that are non ballasted.

You MUST power the ignition module of whatever type from the full 12V supply. Most dolomites are wired to have a ballast resistor
in the loom to the coil plus, which only gives 6V unless the starter is cranking. Take a feed from the fuse box ignition fed (white in green out) Non fused side.

Your symptoms do sound very like coil failure. There are numerous reports of bogus chinese Lucas Gold coils about that dont last.

Jonners

[GTS290N]

The 10v is strange - is this reading taken when the car is running?
What wires and colours do you have going to the ballast resistor +ve? Including any piggybacked wires?
A photo would help.

[mahony]

Read this post, it's not a good idea to run a Lucas sports coil with leccy ignition as the resistance is to high

viewtopic.php?f=4&t=25097&hilit=sports+coil

[Toledo Man]

I recently found out that my coil (a plain gold one so I don't know exactly what it is) is a 12V one and it hasn't given me a moment's bother in the nearly 8 years I have had this car. If your Dolly is back on the road you could come over to mine if you need an extra pair of hands.

[RobSun]

Thanks for the replies. I will answer your questions in order.

Hi Jon, the ignition is wired up to a 12v supply taken from the fuse box as is the coil. The supply for the coil goes to the ballast resistor positive terminal then from negative to the positive on the coil. Negative on coil goes to the ignition in the distributor. The positive terminal on the coil is where the 10v reading is with the meter going to earth engine running. The reading taken from the positive side of the resistor is 13.5 to 14.4v engine running. Engine not running the same readings are 6v and 11.8v. These readings suggest to me the resistor is not reducing the voltage enough when the engine is running and cooking the coil. The coil fitted is a luminition mega spark 3 which came with its own ballast resistor which was recommended to suit the luminition electronic ignition fitted.

Jon I had already found the Wikipedia article and thought it was your work. It was the reason I came to the 12v conclusions.

As I posted earlier the white/yellow wire from the loom gives the same readings as the direct wiring from the fuse box. This is supposed to be a ballasted feed with an inline resistor wire. The resistance has either broken down or was never there. Someone speculated that he thought very late cars and this is one of the last didn't have the resistor fitted.

On line I have seen 4 Lucas coils a102 and 110 ballasted with the 102 recommended for all Dolomites and 105 12v
gold sports. This was rated as 3ohms The other I can't remember the number off hand something like 129 was 12v
recommended for electronic ignitions and rated 1 ohm. This was the one I was considering going for but wanted to
know if anyone had had any experience of them considering my current position and having never heard of them. Out of the frying pan and all that. From the above article it does look like the one to go for and hope it sorts it once and for all.

Dave I still have it sorned so at the moment its only up and down the drive and in the garage running. It wouldn't get to yours anyway. Once this was sorted I was going to ask if you could come over to help with the clutch hydraulics replacement. I've got all the bits but think I will struggle with my back to do it on my own.

Hope that covers all your questions.

Thanks Bob.

[Jon Tilson]

I would discount your readings with the engine running, though they seem sensible depending on the meter.

The static readings are exactly right. The ballast is doing its job, reducing the coil volts by half when not running.
When running you get all sorts of secondary effects which spook the meter.

The occasional absence of spark is worrying. Ensure all your contacts are as they should be and then maybe swap the coil?

You dont actually need a ballasted system with an electronic ignition. I'd just buy a non ballasted coil next time.

Jonners

[RobSun]

Thanks Jon

I may go belt and brasses and strip the carb also. What gets me a little is the mahony's post and the topic he refers to. The ignition system there is the same make as mine and the coil he replaced the Lucas one with is the same as I fitted. They get a successful result I get what looks like a failure again in very little usage. I can't help thinking there may be more going on and maybe the system itself faulty. As said in that post I have also been told by the installer these systems work or dont , there's no in between.

[GTS290N]

There's always an in between. Somewhere, someone will find an in between.
Once the electronics in the distributor gets hot, they can do weird and wonderful things. There's no logic - if it's faulty it depends on what's faulty. As I say, I had exactly your symptoms with an Accuspark unit.
Fuel pump, carbs, coil, fuel filters, fuel line replacement, many hours later an old distributor still on points and hey, it worked. The replacement Accuspark has been behaving perfectly for several years.

[Carledo]

I haven't had Accusparks long enough for one to go wrong (though a mate blew his by connecting the coil connections wrong - for about half a second)
But I have been using Lumenition since 1976 on a wide variety of cars and my experience of them backs up what you have been told, they are all or nothing.

Your symptoms sound to me like coil problems. As your car is a 1300, I presume it doesn't have a rev counter, which makes life harder since my favourite quick check is, when the engine will not run, spin it over and see if the rev counter kicks or is still. If still, it's nearly always the coil that is at fault.

Steve

[RobSun]

Up date

Decided to go down the 12v route and went to Moss Bros who supplied the Mega Spark 3 to seek advice on which Lucas one to go for. They no longer do them saying that since the brand owner shipped the manufacturing from a European company to Chinese they had so many complaints and returns they refuse to sell them. Instead they buy from the original manufacturer Intermotor. They recommended the 111105 gold sports coil which is the original Lucas 105 and it was cheaper than the Lucas on line.

Now the car doesn't splutter or cut out but it will not restart after running a while and the coil still gets warm. Sort out advice from auto electrician at a classic garage fairly local. He asked me to take a set of readings which he says all look in spec. However there was a slight increase in voltage when the engine was run at higher revs. Because I was on my own I could only increase revs on the idle adjust. He suspects the alternator may be over charging but the figures I got he said were not really high enough to cause him concern. Anyway its going in on Thursday so he can give it a good going over to bottom it. He recons with two on it they can push the engine higher and get accurate readings.

As the MOT is now due I've told them to give it a service etc. to save my poor back. The drivers seat backrest is also twisted looks like the frame may be cracked and as I haven't been able to find a good replacement their trim guy is going to strip it and rebuild with new foam etc. This way the cover will match with the existing which are all first class and I can drive it without having to pad one side to try to reduce my increased back pain that I get when driving it.