If you were happy with how the car was running before the spring broke the least expensive solution would be to measure the diameter of the spring wire and try to find a replacement. I have a few used items that may be suitable.
There are specialists who will rebuild the distributor for you and supply springs and weights to get the advance curve back to something similar to the original. Ideally the distributor should be tested on a machine. I believe SLJ has or had one of these.
I have chosen to replace the distributors on my cars with new electronic units which can have the advance adjusted by a Bluetooth phone if you choose the Plus model. These include electronic ignition and have no weights to wear so give more accurate timing.
The units are made by 123 Ignition and cost much the same as a rebuild of a Lucas distributor. I believe the company is based in the Netherlands.
The distributors do not fit properly as purchased. They need about 3 or 4mm machined off the base to lower them and give more engagement with the drive dog. This is a fairly simple procedure that I have done on a small lathe without stripping the unit, just taping up to keep swarf out.
|