Sorry to keep asking questions about ignition stuff but im stumped.

So I got a new battery and new module and im getting a spark now.
The spark seems very small and weak when on the block.

I tested with the multimeter and at ign it is 12 V
When I turn the key and kick it over the starter motor kicks in and I only get about 5 - 8 V at the coil. Is this normal or is something drawing to much?

I made pretty smokey sparks a while back with startermotor, solenoid and dizzy on ignition which would have pumped LOTS of volts through the starter I would guess. Could I have melted the windings or something? How does one test for this?

Thanks in advance
David

5 - 8 Volts is on the low side. Should be 9 - 10 volts. Try it measuring the volts directly across the battery (should be >11 Volts) to see if it's up to the job.If it is OK you'll need to carefully go through all your battery and earth connections in your starting circuit. Measure the voltage drop across each connection while an assist cranks it for you.

From memory, the factory manual tells how to check the armature windings on the starter, I think a special gadget is required (auto gaffer job). Probably easier to swap your starter if you have a spare - check it first by clamping in a vise and give it the defibrillator treatment with jumper cables and a good battery - should spin like crazy!

But its more likely an earthing/resistance problem as GT suggests.

_________________
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.

Thank you both for your replies.
The Battery is brand new and a heavy duty one so it shouldn't be this.

Im a bit dense

What do you mean by voltage drop across each connection?

Like check to see if earth to earth and earth to pos is the same voltage?

Check every electronic component?

What ones would you check first.

Sorry for the dumb questions. I am a newb to electronics ( and working on cars to a large degree).

the voltage is always going to drop when you crank the starter motor, as the starter motor is low resistance and will cause the battery voltage to drop.

if the spark is weak, maybe change your ignition coil, dizzy timing, or even the points in your dizzy,

if the motor is cranking the starter motor is doing its job, measuring the voltage drops will just waste time and battery power

Thank you both for your replies.
The Battery is brand new and a heavy duty one so it shouldn't be this.

Im a bit dense

What do you mean by voltage drop across each connection?

Like check to see if earth to earth and earth to pos is the same voltage?

Check every electronic component?

What ones would you check first.

Sorry for the dumb questions. I am a newb to electronics ( and working on cars to a large degree).

Thanks for the reply
New coil is in
Its an elec dizzy
I think timing is correct, I have taken #1 to tdc and then aligned one with this. It isn't at 2 o clock like everyone said it would be but It is right as far as i know ( 90 degree's out 11 oclock) as it lines up with the flywheel mark and tdc as described on here with rockers and pistons.

Tried to get a mechanic out to have a look but they are all busy it seems.
Im not even sure if it would be a mechanic or a sparky that needs to look at it. Would a sparky set timing? I wouldn't think so but im clueless.

what about your plugs and leads?
do they have the right spacing?

what about your fuel? could be something else which is holding the car back from starting

Not always correct in the case of starter motors.
A starter motor can be damaged when it has been overheated by damaging the insulation on the windings in the rotor or armature. This can cause a catastrophic failure, or just a few windings to short circuit with only a loss of efficiency. In turn this will cause its already low resistance to diminish (draining a higher load from the battery) and also cause the starter motor's available torque to drop away. they're difficult to test at home because the resistance of a starter motor winding is only a fraction of one ohm.

The increased current being drawn from the battery (for a now slower turning starter motor) will cause a large voltage drop for the rest of the car, causing a large drop in the voltage available at the coil.

If the starter motor has had some smoke lett out of it, then I would be looking long and hard at this part of the engine.

_________________
SooperDooperMiniCooperExpertEngineering

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

smoke is always a problem, once it comes out it is very hard to get back in...

maybe you would be better off seeing an auto electrician who can check your electrics, charging circuit & ignition circuit, on an analyser & work out pretty quickly what the problem is. maybe worth the money.

_________________
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.

Hey, firstly please don't say your 'dense' here. The only 'dense' (or dumb) question is the one you don't ask.

Even though you have a new battery, don't assume it is OK, check it. Put your multimeter straight on to the battery terminals and have someone crank the car. Volts should start off (before cranking) aroud 12.5 - 14 Volts and drop no lower than 11 volts when cranking.

To carry out a voltage drop test across connections. put one lead of your multimeter, say, directly on to the battery terminal and then the other on to the battery post clamp. Should read zero volts. Then have an assistant (must be good looking ) crank the car and you should have less than 0.2 Volts. Check all your connections in the same way. If you find one that say goes up to 0.5 Volts or higher, pull it apart, clean it with some emery etc and put it back together and test again.

Work systematically. Start at the battery and go all the way through the different component and back to the battery again. Be sure to check across the starter solenoid too, although when not cranking, you should measure full battery voltage.

To check the voltage drop to your electronic distributor, put one lead of your multimeter on to the live terminal of your starter solenoid and the other on to the live terminal of your electronic distributor (still connected to the dissy). Check again not cranking and while cranking. You might get as much as 0.5 Volt here because of smaller wring. If it appears high, then you can go through the Ignition wiring in the same manner and be sure to check your ignition switch. If you cannot pin point any one item but still have un-acceptable volts to the dissy, you might need to put a relay in the engine bay to shorten up all the wiring. The live feed to your electronic dissy would fed the relay coil, the other coil terminal to earth. Take a live from your starter solenoid to a normally open contact and the other normally open contact to your dissy.

Sorry, I forget what brand / type of electronic ignition your running?

Mate, I hope this helps, I know that this has been giving you grief for some time.

The best way to measure these very low resistances is by the Volt / Ammeter Method of resistance measurement.

Sorry, I didn't quite pick up on that in your first posting (smoke). If you've had smoke from your starter motor, than as Mick says, be a good idea to check it. Just running it 'dry' on the deck may not give any indication that it is US (the front bushes wear and it's a common problem - causes it to 'pole out' and then this can cause it to mechanically over-load, then over heat and then it's game over). Probably the easiest way is to substitute it for another known good one.

Hey Fella's

nvb34n
leads are measuring 1600 resistance and I believe this is ok from reading on here. They are in the right firing order and fuel is good to go. Not sure what you mean about spacing

Mick
The fireworks show was my fault and the copper wire ( non insulated) from the solenoid to the starter motor ( gemini) was touching the dizzy. I was in the car so didn't see where the smoke came from but could see arching, smoke and then flames from the oil in the copper wire... not fun and scary as hell. Starter turns over really well and "seems" to work but who knows.

I did try to buy a bottle of Lucas smoke on Ebay to top it back up but it just kept flying away...

AEG163job
Yeah I agree. I am struggling to find someone that can help though. The place's I have called are all to busy/disinterested in old car's or don't do home calls. I could hire a trailer and a car and tow it down but that will cost a bit and then will have to pay for their service. Im more than happy to pay people for their time though, don't get me wrong.

GT mowog
I will get my girlfriend to help out and will go through and test the things you mentioned. Thanks for the in depth explanation.

Im running a 65dm4 lucas dizzy. It has been giving me grief for a month and im getting sick at looking at the thing.


MICK
Im not sure what running it dry on the deck means. Is that in the vice at home? The thing spins the engine over nicely but I am starting to think that maybe I should just replace it and then if it is good I will have a spare.


ALL
Thanks for your help, im a bit out of my depth and your kind words and help is great!

Cheers
D