Amazon: 1965 122s keeps breaking down!

[Othen]

The one thing helping the OP is that this no longer seems to be an intermittent fault in that it can be replicated quite readily by driving half a mile or so (irritating as that may be). Perhaps if the OP could find a circuit to drive around - around half a mile in length so it isn't too far to walk or tow home, then took his strobe with him until a failure is induced? After a circuit or two (and hopefully not too far from home) when the motor stops again it would be a pretty simple matter to attach the strobe and see if there is a spark. Either way the test would rule out half the possible sources of failure.

The OP seems to have eliminated almost everything already. The problem sounds like either fuel starvation or a failed (nearly new) condenser. The strobe test would rule out one of them. If it is an ignition problem but not the condenser then that would indeed suggest a poor joint in the wiring (including the ignition switch, as was discussed above.

I'm guessing the OP does not have the armoured coil and cable fitted to his motor car (because he has already swapped that) - so it wouldn't be difficult to bypass the simple wiring circuit with a wire and a couple of crocodile clips.

Good fortune OP.

Alan

[arcturus]

when it "breaks down" jump out quickly and check if your coil is too hot to touch.If it is your problem is definitely ignition.Had same problem in my 144

[Volvo Guy]

Originally Posted by Othen

What a conundrum.

Given that the fuel system seems okay it sort of has to be the ignition system. The condenser is favourite - even though you have fitted a new one the symptoms sound most like it being at fault.

Can you recall whether this problem existed before you changed the condenser for the new one? If it did that is unlikely to be the issue.

Good fortune,

Alan

Hi Alan, yes the problem was there before. Thats why I changed the condenser for a new one as I suspected it was causing the problem. I am going to take the new condenser off, fit it on my estate and see how far I get in that car. But it will have to wait until the weekend.

[Volvo Guy]

Originally Posted by VolvoRoyS

Next time it happens you need to check for a spark. Take on old plug with you and when the engine dies, pull off a plug lead, connect it to the spare plug, rest it in the block somewhere and operate the starter. If no spark then at least you will have established that it is ignition. Next remove the distributor cap and flick the points apart. If you don't get a spark then the problem is on the low tension side. This would then suggest a break in the wire to/from the coil.

Roy

Hi Roy. Excellent idea, I'll try it at the weekend. Thanks

[Volvo Guy]

Originally Posted by 142 Guy

Did you do the check with the strobe while the engine was non operational? The purpose of doing the check with the strobe is not to confirm the timing, its to determine whether the ignition is still operational when the engine is dead. If the engine is dead and the ignition is operating you have confirmed that the ignition is not the cause of your mystery problem and you need to focus on fuel delivery. However, your check for fuel at the carbs suggests it is not a fuel starvation problem.

The next time you do a test run and the engine quits, you need to do an ignition check as quickly as possible. In the absence of the strobe, the spark plug test described by VolvoRoyS would work (I personally dislike this test because 50% of the time I seem to manage to zap myself).

If it turns out that the ignition is the problem, you already seem to have dealt with the likely candidates (assuming a new condenser came with the new points). Since it appears that you have exhausted the likely candidates, give some consideration to the possibility that you may have an electrical connection heating up and becoming intermittent / high resistance. This could include the ignition switch. The typical way to check this would be to confirm the presence of +12v on the coil + terminal when the ignition is switched on (when the engine is in its non running state). I recognize that if you have the Amazon armoured coil wire that test is not at all easy. However, it can be done indirectly by pulling off the - coil connection and checking for voltage to ground at that point. Refer to Ron Kwas' excellent Sw Em site for details (about mid way down the page).

https://www.sw-em.com/Volvo%20Igniti...%20Scratch.htm

Hi, the car has an armoured cable on the coil but this has been cut by a previous owner or theif. So swapping the coil is easy enough, there is a connection about 6" behind the ignition barrel. I will test at this point. Thanks

[Derek UK]

"Next remove the distributor cap and flick the points apart. If you don't get a spark then the problem is on the low tension side."

The spark should be very small. If it is a big splashy spark, suspect the condenser. That is in the circuit to prevent sparking destroying the points. Check the condition of your points while you're in there and regap them if needed. They don't last forever and over time you will get a pit on one side and a pip on the other due to the spark transferring material from one side to the other. The points only touch together for a fraction of a millisecond to enable the coil to discharge itself to each plug in turn. If the point surfaces are bad this can mess up this pulse to the coil. Replace if there is any sign of pitting.

[Ron Kwas]

VG;

The current aftermarket, and even Bosch labeled (but still china****!) Ignition Condensers have a bad reputation, often failing, including intermittently, which is troublesome to locate! I too have been bitten by the failure of one...after everything in the ign was checked, adjusted and rechecked, but still wouldn't allow revving the engine, replacement of a "new Bosch Ign Condenser" miraculously cured the issue... As far as Ignition Coils go, although a half century old, they are, and will likely continue to be, highly reliable and the last thing I might suspect, but sometimes, troubleshooting by (temporary) substitution is the most expedient way to proceed...

As Derek has noted, there is indeed a minute amount of contact transfer which occurs with the plasma occurring at the time of (correction!)opening, which the Condenser is intended to minimize, but I wouldn't advise replacement as strongly as Derek advises "if there is any sign of pitting", because by the nature of this inductive contact breaking system, the will always exist some level of pitting, because it occurs with the very first contact opening, and every single opening after that!...setting the timing by way of Static Timing, or checking and adjusting it with a timing strobe compensates for this, even when excessive!...read on...

Just as a life-test, I got 50K miles on one set of points! (See: https://www.sw-em.com/tuneup.htm )...they certainly looked pretty used, and were certainly well pitted after that, but that didn't keep them from being adjusted, and adjustable, and working just dandy!...the tune-up which I finally did (partially out of guilt!) was due to the poor performance effects of the Centrifugal Advance getting stuck at that point...the Points themselves could have gone further(!), but I did decide to retire them after such an impressive service...so I just have to chuckle when someone justifies installing an elec ign by saying they needed to get rid of "troublesome" Points (trouble?...what trouble?)!

Cheers

142guy; Thanks for reference!...and kind words!

[blueosprey90]

Misfire under load, then car dies after short distance.

I have been reluctant to comment, but my money was on a defective condenser. But I'm also wondering if it isn't some loose or frayed wiring, perhaps within the distributor. Maybe the points grounding out when the distributor heats up. But you seem to have checked that so maybe a bad rotor.

Of course, I have no real knowledge or experience, just misguided opinions. Anyway, I'm having my own problems - you just name the car and I'll name the problem!


I found these tests for a Mallory dual point distributor, but I think they can be applied to a Bosch single point distributor.

Coil Check

Remove the coil output wire from the distributor cap. Hold this wire about 1/2" away from ground. Crank engine with the ignition key "on." A reasonable snappy blue spark should be obtained. If spark output is weak, check secondary wiring, and all wiring and connections in the primary circuit. If these parts are okay, remove coil for testing.

Distributor Cap

To test for a secondary breakdown, position the cap so that the inner segments can be seen. Turn ignition key on and crank the engine. The high voltage entering in the cap from the coil will arc across any portion that may be defective. If the cap is free from defects, check the seating of each spark plug wire and clean all surfaces.

Rotor

To test, remove the distributor cap. Remove the coil wire that leads into the cap. Hold this coil wire one-half inch above the rotor. Crank the engine with the key on; no sparks should be obtained. If the rotor is defective, the high voltage spark will pinpoint the exact location of the defect. Replace if necessary.


I had several rotors with surface cracks that I suspected of being the cause of my own persistent high speed misfire on the MGA. As such, I tested the Mallory rotors in accordance with the procedure described. They all tested OK.

But in performing the test, I had what I would describe as a "dirty spark" at the leading set of points. In subdued light, the spark looked to be about 3/8" across and looked like a kid's 4th of July sparkler. Not knowing if that was what it should look like, and thinking that maybe there was a short at the points, I pulled the distributor.

The points looked pitted, so I attempted to file them smooth. I also cleaned up the internal surfaces in the distributor, which was very oily and dirty. I was not 100% satisfied that I had cleaned up the points sufficiently, so I decided to install two new sets of points.

I installed the distributor and retested - the rotor test. Now the spark at the points was virtually non existent. I wasn't even sure if I even had spark, so I put the cap back on and verified by testing with a grounded spark plug at the engine head.

Hope this comment helps.

[blueosprey90]

An additional comment on the strobe light test suggested by 142 Guy. In the US, we call it a timing light.

So you set up the timing light (strobe light) as if you are going to time the car. Then put the induction pick up on the #1 plug wire. Start the car. Look at the light. It should be firing consistently, only faster or slower as you rev or slow down the engine. If it is jumpy or irregular, this suggests condenser failure.

Repeat for all 4 wires. You may find three are nice and smooth, but one is misfiring - or not firing at all (although I don't think this is your problem). That might suggested defective wire or contacts.

[Bracpan]

It was taking all the enjoyment out of owning the Amazon constantly trying to find why it was losing power on hills, so hard to find as it was not constant. I could do a run of 30 miles and it would go rough just a mile away from home then return to normal 5 mins later !! I was losing confidence in the car and could not trust it.
Plus i had already spent a lot of different bits and bobs.
So i bit the bullet and got the 123 Dizzy and as soon as i started i could tell the difference, it idled better and has run perfect ever since.
I think its the best thing i've bought for the car, I got mine of Amazon Cars as they have an unleaded curve fitted into the Dizzy ready.
I know its not a standard fitting but thinking back ive been fitting electronic ignitions since 1974 so i don't care about the originality as long as i get a reliable car to use and enjoy.