If an engine stops or runs poorly it is often due to a problem
within the distributor relating to the points, condenser or general
wear. Regular maintenance can minimise these problems but wear will
always be present.
It is not uncommon on 2½ litre cars for oil to find its way into
the distributor as the drive to the distributor is taken from the
middle of the front inlet cam shaft bearing and oil which creeps up
into the distributor is sure to lead to problems. A small hole drilled
through the bottom of the distributor helps the oil escape but some
will still find its way onto the points.
Wear in the distributor bushes and spindle causes a variation in the
points gap which affects both the dwell angle and the ignition timing
as well as making it difficult to set the points gap correctly. Play
between the spindle and the cam will give similar problems. The points
gap will also close up as the plastic heel on the points wears. This
can be due to roughness on the cam or poor quality plastic.
To make matters worse, several people have commented that some modern
replacement points are of poor quality often with the points not
closing to give full face contact. There are similar reports about
condensers which fail very quickly. Clearly there are several places
within the distributor where problems can arise so is an electronic
ignition kit the solution?
There is a large range of electronic ignition kits now available and a
good place to see the range is Ebay. It is even possible to find kits
which include a new base plate with the trigger head already attached
to it both for the early Bakelite base plates distributors and the
later metal base plate ones. This makes fitting very easy. The question
is: do they really overcome the problems and are they worth the money?
They all claim to give better fuel economy, better starting and
smoother running and in general these claims are met. They use a
triggering head fitted to the base plate which takes the place of the
points and this is activated by a sleeve fitted over the cam each time
a cam lobe passes the trigger head. Since there is no direct electrical
connection between the sleeve and the trigger head there is nothing to
arc and burn so no maintenance is needed. With no points pushing on the
cam there is less wear on the distributor bushes. The gap between the
sleeve and the trigger head is not critical so slight wear and hence
wobble in the distributor has negligible effect as does oil in the
distributor. Of course there is no condenser to fail either. Modern
petrol cars use electronic ignition and these do not have a history of
problems so these kits should be more reliable than the old points
much for theory but how do they work in practice? The first system I
used was made by Mobelec and I fitted it many years ago to my RMF. It
comprised an electronics box and a trigger head. The electronics in the
box enabled the spark pulse to be shaped for enhanced performance. I
made a new base plate for the distributor and fitted the trigger head
to it. I fitted the electronic box to the inner wing under the carbs.
where it could not been seen. This particular kit was for +ve earth and
I fitted similar kits for -ve earth to my RMB and to a friend's RMB.
The kit on my RMF is still working well. I have lost touch with the
RMBs but when last seen they were working well too. All three cars
suffered from oil in the distributor but all ran faultlessly with
slightly better fuel consumption - a total success.
The kits currently available on Ebay are simpler than the Mobelec
ones above having no electronics box. This makes fitting very simple
but looses the pulse shaping ability. So far I have only fitted one of
these which was -ve earth and included a new base plate. Fitting
involved removing the old base plate, fitting the new one, connecting
up a couple of wires, sliding the sleeve over the cam and giving the
ignition timing a fine tune. It was very easy and quickly done as well
as being virtually undetectable. I have left the old base plate in the
car just in case anything goes wrong but I do expect to use it. After
all, I have carried the old base plates in my RMF and RMB for many
miles and never had to use them. I cannot comment yet on fuel
consumption but the engine is running very smoothly. The illustration
shown here is typical of a kit including a new base plate. The blue
plastic sleeve fits over the cam.
As regards costs, a kit on Ebay costs in the region of £40 to
£50 depending on the make and whether a base plate is included.
The one illustrated here is for for +ve earth and retails at
£49.99 including P&P at the time of writing. Compare this to
a new set of points at about £16 and a new condenser at about
£5 and how often these will have to renewed. Also consider the
cost of refurbishing a distributor which has worn bushes or worse.
There may also be a saving on petrol too. Clearly there is potential
for a considerable cost saving over the forth coming years as well as
an improvement in running and reliability.
The only obvious drawback is a departure from originality which is
unlikely to be noticed as the only indication is an extra small wire
running to the distributor..
So if you want your ignition system to be as reliable and trouble free
as those on modern cars, why not make the change? You might extend the
life of your distributor too.