Let's have a look at the distributor on the Viva engine. The type that you will come across is the Delco D202 type.
There are alternatives but more on that later.
Note: This distributor is generally regarded as a bit of a poor relation to the one found in contemporary Opel Kadetts, despite the fact that the Viva engine took its cues from the Opel unit. The Opel distributor has a much greater points surface area and better location.DISTRIBUTOR SHAFT WEAR
This occurs because the types of bearing metal used (shaft and sleeve) are very similar, rather than one metal being, say brass.
However I think there may be another reason behind this: On the baseplate of the dizzy there is a plastic bracket with a ring of sponge on it. This
lubricates the cam which moves the points. However the plastic bracket obscures the word "OIL" on the baseplate. When the car is serviced, there is a hole in the baseplate
of the distributor that you should squirt a bit of engine oil down. This helps lubricate the bearing in the dizzy and helps to stop the bob weights from seizing up. Obviously, a lack of oil
would accelerate the wearing process and there is no other obvious way of oil getting in to the dizzy.
POINTS MOVING ABOUT
This is a fairly common problem but is easy to sort out. What happens is the arm of the points slowly rises up the pivot shaft, resulting in it not making good contact with the part that is screwed to the baseplate.
Result? very rough running at worst or sometimes rough only at high revs. And embarrasing when you're out shopping or whatever.
DRIVE SNAPPING OFF
This has never happened to me but is quite widely heard of. The small flat section that slots into the oil pump drops off. Either the dizzy won't turn round at all or it gets caught and spins very erratically. This is particularly a problem with the "offset drive" distributors. Up to about '77 ish, all Vivas had the offset drive type of set up. Later cars, including the Chevette had centre drive types, greatly reducing this problem as the forces on the "flat bit" were more even. To convert to the centre drive set up, you will need a centre drive oil pump too. And then take the engine out, etc.
There are a few other minor problems too which can cause great aggravation. The first is with the little wire that joins the baseplate to the outside of the distributor. This can snap inside, causing intermittent running, especially with the ignition advanced. A nightmare. Just replace the wire. In other cases, the wire from the points to the coil can break too. This is also a point of great "entertainment".
Don't forget that although the distributors are interchangable, watch out with the advance curves as they may be different to that on your existing car. If in doubt, change the vacuum advance and mechanical advance assemblies over to the new distributor. It's worth checking the Haynes manual too although this really isn't that useful. Vivas had a dwell angle of 35-37 degrees up to engine number 1639738. After this, the angle changed to 49 - 51 degrees.
There are a few ways of improving the ignition so we'll start with the most common
Bit of a tricky one as it depends on what the class of racing allows. Electronic ignition has to be the best, just to keep the engine in tune rather than have those points move all the time. In addition to this, a high voltage coil would help, along with heavy duty ballast resistor (if needed) and some thick racing plug leads. Actually I would recommend 8mm leads for road use even if the engine is totally standard as this helps with economy and starting. Don't forget to separate the plug leads and keep them from being too parallel with each other. Racing / notched plugs should of course be considered.