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No start. - Ray White - 15-03-2025
Hello friends. I am having a problem with 'Trundles' my 1930 Austin Swallow. It won't start.
Given fresh petrol and a charged up 6 volt battery the issue seems to be ignition related.
I gave up on my old 'Rist' coil because although the primary coils showed an acceptable 1.4 Ohms, the secondary coil reading was down to 2.7 kOhms.
With my replacement coil (new Remax) fitted, the engine still won't fire. It shows 1.6 Ohms primary and 6.8 KOhms from secondary. With the 6 v supply connected to a fly lead taken to earth and the HT lead making what appears to be a good contact in the tower. I have still been unable to get a spark with plug end held close to a head stud.
Is the new coil a duff.?
Further testing revealed full battery voltage from both sides of the coil to earth.
6 volts also showing at distributor. With the points open I am getting 6 volts at the primary terminal to earth. With the points closed I am getting 0 volts.
The points are showing 3.9 amps.
The resistance is 0.05 KOhms.
This is all getting above my pay grade. Can anyone help please?
RE: No start. - andrew34ruby - 15-03-2025
I will try to help.
I think you might be measuring too many things.
Coil primary resistance for a 6 volt system should be around 1.5 ohms, so coils are the right ones.
Connect a test light or small bulb across the terminals of the coil and turn the engine over on the starting handle. The light should switch on and off. If not then examine wires, connections and contact breaker points. When this is working, next check is the light flashing if you spin the engine on the starter motor? If not then check the points, clean the contacts, check the size of the gap when open.
When you've got that working, flashing when on starter motor, then you should get a cracking spark if the coil HT lead is held maybe 1/8 inch from the metal of the engine. If no spark then it could be a faulty coil, or a faulty condenser or wiring to/from the condenser.
RE: No start. - John Cornforth - 15-03-2025
Hi
The coil primary voltages and currents look normal, i.e. roughly 6 Volts, 1.5 Ohms and 4 Amps. The resistance of the closed points should be less than 0.1 Ohms so I assume you mean 0.05 ohms not 0.05 kilohms. This suggests the points are clean.
Even if the condenser is faulty I would expect some sort of spark
I agree with Andrew that you should try taking a single HT lead direct from the coil "tower" and either hold it close to earthed metal or better still use an old spark plug with its body resting on earthed metal. This eliminates the rotor arm and distributor cap as a source of trouble.
If that test is passed but stlll no spark from the plug leads, the finger of suspicion points to the rotor arm, the distributor cap (including the carbon button) and the plug leads.
RE: No start. - Ray White - 15-03-2025
I mistakenly said "plug end" when I should have said "distributor cap end". I have taken the king lead out of the distributor cap and held it close to a head stud and expected to see a spark... but there is none. It is a brand new condenser from "The distributor doctor"...although even without one, I would still have expected a spark of some sort.
The points resistance of 0.05 KOhms is the reading. I tried to get a reading with the meter set at 200 but all I could get is a continuity buzzer. Nothing on the screen.
RE: No start. - Charles P - 15-03-2025
I had a set of “new Remax” points fail on me after a couple of days (the plastic heel just snapped) so it’s a brand that I actively avoid now.
I’m inclined to suggest swapping the coil for a known working one
RE: No start. - John Cornforth - 15-03-2025
You should be able to measure points resistance on the 200 Ohms full scale range. Check the meter first by shorting its two probes together. The live feed to the coil needs to be disconnected for this test. Measure from distributor LT terminal to distributor body first, then from distributor LT terminal to the engine block to check that the distributor body is properly earthed. With manual advance/retard distributors there is a moving joint, so contact can sometimes be unreliable unless a "pigtail" is added from distributor body to engine block.
If the points really were 0.05 Kilohms (50 Ohms) the primary current in the coil would only be 0.12 Amps, which doesn't tally with your 3.9 Amps reading. Out of curiosity, how did you measure the latter ?
RE: No start. - Ray White - 15-03-2025
John. I will get back to it later this evening.
Thanks.
RE: No start. - Nick Salmon - 15-03-2025
May be completely useless...but...
https://www.austinsevenfriends.co.uk/forum/showthread.php?tid=9880&pid=106846&highlight=Instant#pid106846
RE: No start. - Ray White - 15-03-2025
With 6 volt supply and selecting 20A (DC) on the meter and taking a reading across the points I am now getting 0.12 amps.
RE: No start. - John Cornforth - 16-03-2025
Hi
I'm not sure what you mean when you say you are taking a current reading "across the points".
Voltage is measured across a component by connecting a voltmeter in parallel
Current is measured through a component by connecting an ammeter in series
The current through the coil with the points closed should be about 4 Amps, i.e. 6 Volts divided by 1.5 Ohms. With the engine running this current pulses on and off in about a 50:50 ratio, so the average current is about 2 Amps.
If your coil current really is 0.12 Amps you have a problem, but if you have connected your ammeter in parallel with the closed points it will only be measuring part of the coil current.