Went out to run a few errands in the MK2 today – it’s running really nicely. That’s fairly remarkable as it happens, since it doesn’t seem to have had an engine rebuild since new. Admittedly it has only covered 68 thousand or so miles but 51 years is an awfully long time for it to be in one piece!
The previous owner had lavished a fair amount of attention on the external tune of the engine before other projects had forced him to leave it running poorly at the time Cherine and I took the car on. Although it didn’t take long to get the car running well it turned out to be a slightly less than straightforward job, mainly because one of the reasons it was running badly was that it just hadn’t been driven for years. This led to a sort of catch 22 situation with the car: It needed a good run for the rings to bed back in, for the valves to start seating properly and to blow away all the “cobwebs”, but it was running too poorly to want to take for a good run.
There were two main problems with the car: The ignition spark was below par and the carburettors needed attention. The carbs had been freshly overhauled by a specialist and looked lovely, however one of the details on the invoice (for which extra had been charged) was the manufacture of a “new pump rod”. Sure enough the accelerator pump rod on the rear carburettor was newly made and not original; it was also too long and the rear pump was doing nothing until the throttles were more than halfway open. Fixing this improved matters and after a few miles the engine began to run evenly although performance was pretty poor. Sorting out the ignition brought the performance back – although if the compressions had been better at the time I’m sure that the ignition problems would have been less dramatic than they were. The problem was the electronic ignition conversion which had been fitted: With the electronic ignition fitted the car needed ‘L’ to be selected on the transmission quadrant in order to make it asthmatically to the top of the hill where we live. With a nice overhauled DMBZ6A distributor and some copper leads, it flies up the same hill in intermediate gear. Electronic ignitions are not all made equal – some of them are compelled to use the original ignition coil and insist on the use of silicone H.T. leads. Unfortunately old coils just weren’t designed for this type of lead so the spark is actually weaker than standard. The moral of the story is to make sure that your electronic ignition either has a high energy coil or that it can use copper H.T. leads!
And the moral of the carburettor story: Just because it has been professionally rebuilt it’s still not safe to rule it out as the cause of the problem!