Updated 20 August 2015, the job of replacing HT leads added lower down. |
HT (High Tension) or plug leads.
Most spark plug leads on an Austin Champ could be 60 years old and the plug lead casing can crack and the current can short to earth and cause a miss-fire.
The plug lead on a Champ is an assembly of the outer wire mesh braiding and the inner spark plug lead. If the outer mesh braiding is good then it may be worth re-threading with new spark plug lead.
The diameter of the plug lead on a Champ is 7mm. But, what quality of lead?, There is lead marketed as, 'Performance' for racing cars, hot rods, etc. There is red plug lead on eBay at £1.21 a metre and another with 'silicone' in the description for £2.52 a metre. If I did mine, and without in-depth knowledge of whether the Champ needs high quality plug lead, I would try the last one or go to a Lucas agent and ask them.
The following article appeared in CHAMP NEWS, issue 22. written by a Champ owner, Richard,
"I think many starting and running problems on Champs are due to HT faults. My recommendation is to go to a Lucas Service Agent and order a roll of 10 metres (Editor: I found 3 metres did plug and coil leads) of "Hypalon" HT lead, part number 857158. I bought some about 4 years ago and it was not expensive, and I assume it is still available. It's a plastic material, not silicon rubber, but much higher specification than the cheap PVC leads that were often used in the 70's. I have used it on another classic car with great success, where it is subjected to very high temperatures.
It has a copper wire core, is black in colour, 7.00 mm dia. and is very flexible and heat resistant. It was a bit of a struggle, but I was able to pull out all my old Champ leads, and feed the Hypalon through the conduits. The coil lead was a bit tricky and took several attempts, I had to feed a draw wire through first, and use silicon grease to lubricate it. By using the silicon grease I had no problems with the rubber grommets and sleeves.
To answer a reader's question, it's easy to make the connections for the spark plugs. You strip the end of the cable back about 3/4 inch and tease the conductor strands into two bunches, which you twist into 2 separate "pigtails". Put the grommet and elbow over the wire, and the porcelain part, then fit the "cup" washer. Then put the "open top hat" over the pigtails, fold the pigtails outwards into the slot, and pull the cable back so that the cup is pulled up so that the pigtails fit into the slots made in the edge of the cup. Hold the cup with a pair of pliers, and turn the "top hat" with a screwdriver half a turn so that the pigtails are drawn under head to secure everything. Trim off any excess - job done. I found it best to do this first, then feed the cable into the conduit. At the other end, I discovered the Hypalon was easily pierced by the spikes in the cap, as the Hypalon is very soft and flexible. I gently pushed it onto the spikes with a screw driver, if you try to do this by pulling down the cover you may find it will crack."
(Editor) If the outer braiding is damaged then it is better to find new sets of leads, they come as two assemblies: plug numbers 1 & 2 and numbers 3 & 4 and the plug number is stamped on a metal collar around each outer braiding.
The reason the leads come as two assemblies is that the leads, 1 & 2 and 3 & 4 are joined on a flange where the lead sets enter the distributor.