2021, August. Taith Cymru and Ignition Trouble

 22nd August:  Taith Cymru, DNF

The Taith Cymru is one of the top classic tours in Wales but had been cancelled in 2020 and delayed by the various fluctuations of the Covid restrictions.  They had finally managed to rearrange a date for 22nd August so we were really looking forward to it. The weather was again changeable so we decided the FHC would be the best choice to use for this one. Starting from the Old Railway Line Garden Centre at Three Cocks just north of Brecon, the 140 mile route used many the classic night rally roads in mid-Wales.

However, after about 40 miles it was on one of these classic roads , the Abergwesyn Mountain Road, that the first hint of a problem began.  The engine would occasionaly mis-fire then clear again.  As the symptoms got worse I noticed that each time it happened the rev-counter dropped to zero, indicating ignition failure.  It would then run normally for a while before doing it again.  We stopped and I checked for anything obvious like loose connections but couldn't find anything wrong.

Approaching the Devils Staircase on Abergwesyn Mountain Road

 By the time we reached the lunch halt at Lampeter Rugby Club the intermittent misfire had got quite bad so I decided to have  more serious look but couldn't find anything.  Best option was to try some of the spares we carry.  First and easiest thing was to try a new coil. The engine started and ran fine so it seemed to have cured the problem, but a few miles down the road the mis-fire came back. This time I changed the Lumenition amplifier module and again it seemed to have cured the problem, only for it to come back again. It was fine for a few more miles and then mis-fired badly only to clear again.

To me this meant the only other possible culprit must be the Lumenition optical switch inside the distributor. This is a fiddly job so I decided to struggle back to the Lampeter Rugby Club car park where we could work on it safely, rather than at the side of the road. Some of the club members were still there and very kindly gave us coffee and cakes while we worked on the car.

I finally decided to call it a day and called the breakdown, so we adjourned to the club until help arrived.  I expected a recovery truck but a young guy in a Transit sized van arrived and it turned out he had never even worked on a car with a distributor!

After I explained how it worked we tried all the connections and various voltage tests and even tried mounting the coil vertically instead of horizontally because his boss told him that was how they should be(!).   The car started ok and appeared to be fine so we set off for home with him following behind just to be safe.  We went about 10 miles and all seemed well so he turned back and we headed on home.

You may have guessed the next part, because it was not long before the problem came back.  By now we had passed Llandovery and were on the A40 nearing Brecon.  A few good miles and then the mis-firing. We struggled past Brecon but it was now getting quite bad and with evening approaching I did not want to be stranded at the side of a busy main road. As we reached Abergavenny it was becoming difficult to maintain any progress so I parked up in the main bus station car park and called the breakdown again. There always used to be a nice cafe here open all hours but in these strange Covid times on a Sunday evening it was closed, but at least the toilets were open! 

When the breakdown truck finally arrived it was nearing 10pm. The driver had already called me and said he could only take one passenger in his cab so could I call anyone for a lift or get a taxi. Unbelievable, but apparently it was due to the Covid regulations in Wales so I called  my old navigator Oliver Tomlins who agreed to turn out and drive the 60 miles to pick us up and we all arrived home just before midnight. Not our best day out.

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Lumenition Repairs

After the tribulations detailed above I went through the ignition system to see if there was anything I had missed but couldn't find anything obvious.  The only item of the system not replaced was the optical switch inside the distributor so I needed to replace that.   I did have one in the car but it requires the wires to be taken out of the connector plug so they can be threaded through the distributor body and the plug re-fitted.  I swapped the optical switch out and adjusted the ignition timing which had moved because the switch was very slightly different.

I drove the car for about 50 miles and the mis-fire was cured.

Brillant!