I've finally progressed on my Mini restoration project to the point where the car is actually on the ground and ready to be started, but.... of course there's no joy when I turn the key.

I've done some diagnostic work and here is what I have so far:

The fuel system is working- I know this because I've cranked the car over many times and have had to clean the spark plugs of excess fuel.

I tested the resistance of the coil using a multimeter and verified I'm getting 3.2 ohms on the primary and 14.89 kilo ohms on the secondary.

I tested the voltage to the coil by disconnecting the white/back lead to the coil and and using a multimeter to bridge the positive side of the coil with ground. I verified I'm getting 12.7 volts.

I disconnected the ignition wire going from the coil to the distributor and connected it directly from the coil to a spark plug while grounding the spark plug to the engine. I verified that there is a spark (blue-ish color) when I turn over the engine.

Using the same setup as in the previous paragraph, I also removed the distributor rotor cap and turned the engine over until the points were open. I then repeatedly shorted the points with a screwdriver and verified that the spark plug had a spark (blue-ish color).

As the last test, I then reassembled everything back in place. I then removed one of the spark plugs from the cylinder head and simply grounded it to the engine while turning the engine over. Most of the time it does not spark. Every now and then it will spark (like one of out 10 times) and the spark is orange in color.

Given all this information, my assessment is that there is something wrong with the distributor (either with the cap, rotor, or perhaps the points gap). Would this assessment be correct or is there any other troubleshooting steps/information I may have left out that could lead to a different conclusion?

I have to admit I'm pretty new to the mechanics of ignition systems and I've been doing a lot of self-research and learning about how everything works. But I'm also quite certain that all my learning can't make up for lack of experience. Hopefully that's where you come in! Any comments or suggestions would be appreciated- been wracking my brains out over this.

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- Merrick
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3/71 Morris Mini K

Perhaps it is in the explanation but I find the above to be a bit strange.

For instance, you say you disconnected the white/black wire to the coil and then measured 12.7 volts on the positive side of the coil. This can't be as the white/black wire is what will be supplying voltage to the coil.

But hang on, after writing this I had a thought, are we talking positive or negative earth

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1964 998cc Cooper
1971 Mini K x 2
1972 Clubman GT

The voltage at your points is a little low considering the engine is not turning over when you took the measurement. The battery voltage should be closer to 13.7 volts. It doesn't mean much, but these last volts are where the lion's share of battery capacity is stored at. Once you turn the engine over and draw 100 amps, the battery voltage drops to a much lower value and makes it much more difficult for the spark plug to be fired by the coil. This is shown by the orange spark you are getting outside the engine. Put the spark plug under compression, and this makes firing the plug impossible as the gap resistance increases with air density under compression.

Try charging the battery up to get full voltage, or replace the battery. But as a tickler, try changing the coil out with a known good unit as well. The voltage is low, but for it to fire only 1 in 10 might also show a problem with the coil or points, but charge the battery to full first.

Excellent problem description by the way..very thorough.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Steve, my car is indeed negative earth:)

Mick, thanks for the suggestion regarding the voltage. The battery is new and was just charged, but after reading what you wrote I went ahead and tested it with my multimeter. It's indeed putting out 12.7 volts. I also do remember that before I started my restoration project (and all these components worked- including the coil and distributor) I was using a different battery. It was a large battery that didn't fit in the battery box. That battery however, I do remember distinctly giving almost 14 volts (maybe even more).

Does this mean the battery I bought is defective?

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- Merrick
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3/71 Morris Mini K

Maybe not Merrick, check the electrolyte levels in each of the cells and give it a charge first overnight. If the battery still reads low after all this, then take it back.

Just to be sure also; the white wire goes to the +ve side of the coil, and the distributor wire connects to the -ve.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Sounds like decent spark right up to when it gets to the plugs.

Do you have another set of leads you can try? How old are the leads you are using?

cheers

Jacob

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'72 Clubman Van - 1022cc, 295 head, 731 cam - Daily Driver
'69 Morris 1100 S - Dinged by a bus, in shed under repair
'64 Morris 1100 - Early 1100, long term project

Sounds like the similar thing that happened to me it turned out one of the wires I had connected to the coil was grounding the coil

NEW QUESTION!!!!

I am trying to start my engine that has been pulled apart and hasn't been started for a while and I am having some trouble..

What does it mean if i turn it over then it fires but then the starter motor just spins?
Does anyone understand that??
Its like the starter wont stay engaged with the flywheel once it fires a bit.....

Any thoughts/ideas????

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Tim
Dusk Blue
1964 850

Could be the starter bendix (drive pinion) is sticking on the shaft.
Take the starter out, wash the pinion assembly with thinners, when dry blow some graphite powder into the splines.
Don't use oil or WD40, as it'll cake up with crud again.

Otherwise it's because the motor is just giving a few isolated kicks, enough to throw the pinion out of mesh but not enough to run. Check your plugs, points, timing and fuel.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Ok, ill give it a go tomorrow.
Thanks doc

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Tim
Dusk Blue
1964 850

What carbie / s are you running ?

Is the choke setup working properly ?

Your not trying to pump too much fuel into it are you ?, ie; pumping sh!t out of the throttle
whilst winding it over . If i do this to mine , ( twin su's ) it'll do the same as you describe .

that's weird, because SU's don't have a throttle pump... theoretically pumping the accelerator pedal when the engine isn't running does nothing

Well, doc was right, the starter was a bit gummed up. I gave that a clean and it seems to be working a bit better.
Its firing now and close to running, but not quite.
As for the Carb, it is a 1.5". And that is the tricky part... cos i am not certain that the Carb is good. When i bought the car it was running, but on a 1.25" Carb. The 1.5" was amongst the parts i got with it. I had a quick look over it and checked it out, and it seems OK.
The plugs were well and truly wet after trying to start it before, so its definitely pumping in fuel.
I have checked for spark, and it seems all good there, so i have given the plugs a clean and will give it a go in 30mins or so.

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Tim
Dusk Blue
1964 850

IT'S ALIVE!!!!!!
well, sort of..
Here's the video, feel free to comment and critic.

So it wasn't too keen on running without a lot of choke.
So where to from here?

http://static.photobucket.com/player.sw ... 0162-0.mp4

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Tim
Dusk Blue
1964 850

I think you should check your ignition timing. Also valve clearances if the head has been off. Once it is running a bit more smoothly, you can then concentrate on fuel mixture and possible air leaks in the induction system if it refuses to run properly without using a shirtload of choke.

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1967 Cooper S - new front bearings to do.
1965 Cooper S shell - Slow progress. No time or money!
1966 Deluxe- next rustoration!
Mk 2 & XJ6 Jags. Less said the better.