Why my car died. Autopsy results.

[abowie]

It was the points. It's always the points.

I've never seen this before though. The movable electrode was loose. When I checked the point gap with a feeler gauge with the dizzy in the car the gap was spot on.

BUT I couldn't crank the engine AND watch the points at the same time.

With the dizzy out; see the video:

http://www.projectetype.com/index.php/c ... 3&modid=77

[mgcjag]

HI Andrew.....Had 2 sets of ponts burn out due to condensor i assume...and purchased new that were supposed to be good quality that had similar operational faults as u show in your video.....just fitted a pertronix....but have a set of points and condenser in the car as a standby.......all the best Steve

[christopher storey]

What a very strange fault . I've never seen anything like that in 56 years of playing with points !

[PeterCrespin]

What a very strange fault . I've never seen anything like that in 56 years of playing with points !

Agree. Bizarre but fixable with a hammer and drift?

Pete

[rolando38]

why don't you want to change to electronics ?

[abowie]

why don't you want to change to electronics ?

Interesting question.

I have an EDIS in my other coupe. Prior to that it had a Pertronics module that burnt out while I was driving it. No idea what went wrong but it got hot enough to melt into a sort of blob in the dizzy. It came with the car and so was probably quite old.

In the (distant) past I have owned MGBs and AH Sprites. I always fitted electronic ignition in those cars. Those units were optical and worked well.

This car came with points and up til now has worked fine. When I took possession of the car I gave it a service and that's when the faulty points in the video were installed.

I'm in two minds as to what to do. I actually have a new in box Pertronics module in the shed. For the time being I'll probably leave it as it now has proper Lucas points in it rather than the "el cheapo" ones I used. If I have any further trouble I suspect I'll put the Pertronics in.

[abowie]

What a very strange fault . I've never seen anything like that in 56 years of playing with points !

Agree. Bizarre but fixable with a hammer and drift?

Pete

I thought about it. But then I just called it names and threw it in the bin.

If you look closely not only is the electrode loose, but the spring has bent as well.

[AussieEtype]

Both my current old on road vehicles (Haflinger and Landrover FC101) were both points (double points in the 101) and always caused issues of one sort or another. Both now electronic and no further issues. My other two old 50s landies will also be getting electronic when they come back on the road.

The V12 E-type still has its supposed problematic original OPus system but it still works OK. Its fuel pump has been changed from points to electronic.

I would never go back to points in any vehicle it is just not worth the grief.

Garry

[abowie]

I was bored...feel free to suggest improvements.

No spark.


Symptom: car won?t start or run at all.


NOTE: assumes NEGATIVE earth, points in distributor.


To Confirm: Put a plug tester in series with a plug. It should flash when engine is cranked. If no flash check other plug leads as well. No flash = no spark.

If you do have a flash the problem is NOT spark per se, although it MAY be plugs. See 9.
Otherwise the problem may be timing, or fuel or compression. These steps will not help those things.

Take each step one at a time, in order. At the end of each step try to start the car.

1. Battery flat.
If the car cranks over it is almost certainly OK.

2. Engine earth.
Spark requires a good earth to the negative terminal of the battery. Check that the engine is earthed with an ohmmeter or voltmeter between the battery and the block.
Visually inspect the engine earth lead (LHS behind the reaction tie plate). If in doubt run a thick cable (jumper lead) from the battery negative terminal to the engine.

3. Check power to coil.
Remove the positive connector to the coil. Put a 12v test light in series and turn on the ignition. The light should come on and be steady.
Jiggle ignition key to eliminate switch fault.
If no power, run a wire directly from the positive battery terminal to the positive coil terminal and try ignition. If it works problem is between battery and positive terminal wire. Check fuse 7 and chase wiring with multimeter. Recheck ignition switch. NB starter button will not affect spark.

4. Check points are opening and distributor is turning.
You can do this visually. Remove dizzy cap and get someone to crank the engine. You should see the points open and close. Use a torch; it?s dark down there.
Put a 12v test light between the negative coil terminal and the black/white wire to the distributor. Crank the engine. The light should flash off and on as the points open and close. This should work with electronic ignition modules as well because what you are testing is the circuit through the points (mechanical or electronic) to earth.
Note: the light may stay on or off when not cranking depending on whether the points stop closed (likely) or open (unlikely). This isn?t important.
Check the points gap (14 to 16 thou) and inspect the electrode faces for pitting. If any doubt replace points and reset gap. Even when you?re sure it?s not the points, suspect them. It?s always the points.

5. Condenser.
A dead condenser looks just like a good condenser. Just replace it. They can be tested with an ohmmeter but if you put a new one in and it doesn?t fix the problem it probably isn?t the condenser.

6. Check the coil.
If the points are working and the condenser is OK. Get a spark plug and a plug lead. Connect the plug lead into the HT coil connector. Earth the plug by resting it next to a head nut. Turn on the ignition. Use a nonconductive (plastic) tool and open and close the points manually. (Alternatively you can connect a wire to the negative LV connector and tap this on an earth.) There should be a spark on the plug each time the points open. If you have spark the coil is OK. Move on to 6.
If NO spark AND you are happy with 1-4 above, the coil may be faulty. Check the resistance of the low voltage (primary) circuit by connecting an ohmmeter to the two LV terminals. This should be between 0.5 (low resistance/sports coil) and 3.5 ohm (standard coil). Check the HT (secondary) circuit resistance by measuring between either LV terminal and the centre HT terminal. This should be in of the order of 5000 to 10000 ohm. Note that coil failure can be exacerbated by heat so even if it checks out cold it may be faulty hot.
Replace the coil anyway with a known good one. (You can just sit one next to the old one and connect the 3 wires to it).

7. Leads
Remove the coil HT lead. Inspect for cracking or corrosion. Coolant can leak from the thermostat housing down onto the top of the cap and cause corrosion, especially with ?screw in? contacts.
Check resistance with ohmmeter; it should be virtually zero with copper core wires.
Check the resistance of each of the plug leads by removing the plug cap and using a multimeter between the end of the wire and the corresponding contact inside the distributor cap. With copper core wire it should be virtually zero. If not check the cap socket for corrosion.
Modern cable resistance is more complex and you would need to check the figures with the manufacturer. As a general guide though a lead should be between 2000 and 8000 ohm.

8. Plug caps
The original plug caps have a carbon resistor in them. They will have a resistance somewhere between 5000 and 15000 ohm. Modern or reproduction caps should be spot on 5000 ohm. If you suspect the caps, replace or eliminate them. You can solder a ring connector onto a fine 1? self-tapping screw. Screw this into the lead in place of the plug cap. Use the ring connector to connect directly to the threaded end on the spark plug.

9. Spark plugs.
Remove the plugs. Check for fouling and check gaps. If no success, replace with new plugs.

10. Distributor cap
Inspect for cracks or corrosion. The cap really should look brand new inside. Clean up the lead connector sockets if at all corroded. The central contact for the rotor button should have a resistance of the order of 30000 ohm. If the cap looks OK still try replacing it with another one, or a known good cap and set of leads.

11. Rotor button
Inspect and replace if it looks worn, pitted, burnt or otherwise faulty. Try another one anyway if it looks OK.

12. Distributor
Remove the distributor and carefully inspect it. Ensure that it wired correctly. Specifically check the insulators between the points and the coil and capacitor leads are in the correct place.
Check that that the coil lead is connected and conducts to the capacitor lead.
Check that the internal earth lead is connected to the distributor body and the centre plate.
Check that the distributor turns freely and is mechanically intact.
Check that there are no small screws or other foreign parts loose inside or causing a short.


Other things
If you have got here and not fixed the problem.
The checklist above is fairly complete. Sometimes though electrical components can look OK but be faulty. Replacing each component, one at a time, with a known good (not necessarily new) component will sometimes smoke out a mystery.

[abowie]

What a very strange fault . I've never seen anything like that in 56 years of playing with points !

I bet they never had this trouble in Spitfires.

[JagWaugh]

Andrew
To make your "mother of all ignition diagnosis" a bit more generic, change 3 to include

if car has a ballast resistor
continuity of resistor = roughly 4 ohms
Is Ballast resistor fed when Starter turning?
at least 9v at coil side when key is at "Ign on"?

Andrew

[mgcjag]

Hi All.....If u use a pertronix then your coil circuit must be a resistanc of at least 3ohm, also if the ignition is left switched on it could burn out the unit...Steve

[Gfhug]

I bet they never had this trouble in Spitfires.

Triumph or Vickers Supermarine?
If it's the Merlin or Griffon engined ones, then, yes, they too can/did give problems. Just a few more plugs (24) to check!

[JagWaugh]

With magnetos you don't need no steenking points. OTOH I wouldn't suggest trying to replace the plug wires with a hangover...

[christopher storey]

Magnetos most certainly do have points ! and quite difficult to set up they can be

[PeterCrespin]

No battery maybe, buy on every car or motorbike magneto I've worked on you still have points. My Norton has a Lucas K2FC mag.

In fact even fixed-ignition flywheel magnetos on everything bar lawn mowers or strimmers with electronic ignition have points don't they? I'm guessing the Merlin itnition system wasn't battery and coil but maybe multiple magnetos, each with multiple points?

[JagWaugh]

Correct, found myself unable to resist using "We don't need no steenking...". It's ok, I'm fine now.

Andrew

[JimmyS]

I remember my old ex Rolls Royce employee colleague telling me that the RR Merlin's magnetos had platinum points. A quick check on Google for confirmation lead to this site http://www.splitdorfreg.com/blancard/magproblems.html which I think Pete will like...

Jim

[PeterCrespin]

I remember my old ex Rolls Royce employee colleague telling me that the RR Merlin's magnetos had platinum points.

They were all platinum back in the day AFAIK, or at least a facing chunk of platinum over something cheaper. I remember seeing plenty of points where you could see a joint. Think they switched to tungsten later?