12 replies to this topic

[daddums]

Hi, I'm new here. I've real all the posts I can find, including KernowCooper's helpful guides, but am still puzzled.

 

1991 Mini City E

I think the block is the original 998 one. Serial no 99HE20...

It has a 12g940 head, which I think is from a 1275 metro.

 

It has the 59d dizzy (which I think is original), but it looks like it's been converted to electronic ignition.

It is currently fitted with a non-ballast intermoto coil - pn 11040B aka GCL216 - which according the research I've done is suitable for pre 83 cars with points.

 

I'll give more background below, but my first question is which coil I should get - I'm thinking of getting the MSC105 gold type, but wanted to check.

 

I had reason to suspect the coil because I was cranking the engine after refitting the head and saw sparks jump between the primary and secondary terminals. I measured resistance between the primary terminals as 2.7 ohms, which seems a bit low. Resistance between primary and secondary terminals measured at 35kohms.

 

More backstory (if you're interested).

I bought this mini as an unfinished project to work on with my 16-year-old. I had help to get it running and on the road last year, but found that after driving a number of miles, the engine would start misfiring, and would lose power, or even stop running all together. On checking the spark plugs I found out that the plug in cylinder 2 was getting oily. The others were getting fairly black, but I put this down to running a rich mix.

I fitted a new set of spark plugs and did few more local runs, whilst doing some research on the cause of the oily plug. Eventually, though, performance deteriorated again, with low power, especially up hills, it sounded like it was running on 3 cylinders. This time, a new set of plugs didn't fix things. I did a compression test and don't remember the numbers, but they within an acceptable range. I thought it was worth having the head off to inspect the head gasket. I found no obvious signs of leaks or damage, but removed the valves, cleaned them up, as well as all the surfaces and replaced the head with a new gasket. After reassembly, the engine still won't start. I'm part way through moving house so don't have my compression tester handy to check again. I'm getting fuel to the carb (HS4) - I haven't checked anything else on that. I cleaned up the rotor on the dizzy and have checked that each plug is getting a spark. Any suggestions on what to try next would be most welcome! Thanks for reading my little essay!!

[timmy850]

Do you still have the pink ballast wire to power the distributor? How many volts are you getting at the positive side of the coil when it's on?

 

A gold coil is 3 ohms which is a low power coil to suit a non-ballast points setup

[daddums]

Do you still have the pink ballast wire to power the distributor? How many volts are you getting at the positive side of the coil when it's on?

 

A gold coil is 3 ohms which is a low power coil to suit a non-ballast points setup

 

Thanks for the reply.

There is a red and black wire going from the electronic ignition module in the distributor to the +ve and -ve terminals on the coil.

Which looks like this https://www.minispar...ack-43d-45d-59d

 

There is no pink ballast wire.
I'm reading around 12v on the positive side of the coil.

 

It looks like there are two types of gold coil available:

105 for non ballast setups - which MiniSpares say can only be used for Minis up to 1982

110 for setups with ballast

[Cooperman]

The next time I need a new coil I will go for a Pertronix 12 volt 'Flamethrower'. The current Lucas coils are not of the quality they used to be and I currently use a Delco coil in my 1964 car and a Lucas Gold Sports in my 1990 rally car.

There were a few problems with Lucas coils a while back, but they may be OK now.

[timmy850]

The pink wire would have been the feed to the coil from the loom, rather than from the distributor. It is the ballast wire and lowers the voltage

If you have 12 volts at the coil then it’s worth next checking which electronic module you have fitted. Does it have a part number on it?

Some modules have variable dwell and can fire a 1.5 ohm coil (or even 0.8 ohm) at 12V, which will give better performance

Some lower quality modules can only fire a 3.0 ohm coil

[daddums]

The pink wire would have been the feed to the coil from the loom, rather than from the distributor. It is the ballast wire and lowers the voltage

If you have 12 volts at the coil then it’s worth next checking which electronic module you have fitted. Does it have a part number on it?

Some modules have variable dwell and can fire a 1.5 ohm coil (or even 0.8 ohm) at 12V, which will give better performance

Some lower quality modules can only fire a 3.0 ohm coil

 

That's super helpful - I'll have a look tomorrow and see what I can find. I'm annoyed I didn't take any pictures when I was working on it.

[timmy850]

The next time I need a new coil I will go for a Pertronix 12 volt 'Flamethrower'. The current Lucas coils are not of the quality they used to be and I currently use a Delco coil in my 1964 car and a Lucas Gold Sports in my 1990 rally car.
There were a few problems with Lucas coils a while back, but they may be OK now.

I’ve been using a Bosch SU12R coil and it’s been working fine so far. I’m not sure how available these are in the UK

SU12 is a 3ohm
SU12R is 1.5ohm

[nicklouse]

There is some good reading in the FAQs 

https://www.theminif...tributor-types/

[daddums]

Ok, I've had a look and I am definitely getting 12V at the coil.
 
I can only find the remains of a sticker on the ignition module. It reads ___C-V4.
I've tried to attach a photo- it's not the best because I was working in the dark.
 

[cal844]

That is 100% an electronic distributor, possibly an aftermarket kit (someone else will be able to help!)

If there is fuel in the cylinders, is there a consistent, strong spark across all 4 bores?

What have you set the valve clearances to?

Check the resistance of your longest spark plug lead (removed from the dizzy cap and plug)

[timmy850]

That does look like an Aldon/Pertronix Ignitor 1 module. The best way to confirm this is to check the dwell reading as they have fixed advance and recommend a 3.0ohm coil

https://pertronixbra...-4-cyl-43-45-59

https://www.minimani...-Points-And-29d

https://www.somerfor...-45d-red-points

Edited by timmy850, 28 January 2025 - 10:33 PM.

[daddums]

That is 100% an electronic distributor, possibly an aftermarket kit (someone else will be able to help!)

If there is fuel in the cylinders, is there a consistent, strong spark across all 4 bores?

What have you set the valve clearances to?

Check the resistance of your longest spark plug lead (removed from the dizzy cap and plug)

 

I'm getting fuel and spark in each cylinder. Not sure how strong the spark is.
I set the valve clearances to 12 thou. Why do you ask?
Resistances on the HT leads range from 4.7 to 6.4 ohms.

.

[daddums]

That does look like an Aldon/Pertronix Ignitor 1 module. The best way to confirm this is to check the dwell reading as they have fixed advance and recommend a 3.0ohm coil

https://pertronixbra...-4-cyl-43-45-59

https://www.minimani...-Points-And-29d

https://www.somerfor...-45d-red-points

 

Ah thank you - yes these look familiar and the minimania and somerford ones even have a sticker which matches my one.

 

I don't think I have the kit to do a dwell reading, unless there's a way to do it with a regular multimeter?