Most of the visitors on this site do not have to concern themselves with having to adjust the ignition timing. It's already catered for by the electronic ignition.
However this is Retro-Renault and there are quite a number of older cars that still require the timing to be adjusted manually.
So what gets adjusted?
Well that would be: the timing itself, how far advanced/retarded it is and the points gap, which alters the dwell angle.
If you read the other article about the Ignition System it will explain a lot of the things you are unsure of, like advance and retard.
It doesn't go into Dwell or Points though.
So whats Dwell?
This is the angle or percentage that the distributor cam goes through which the points actually touch (Dwell together so to speak). The longer they are together the bigger the spark, the shorter they touch the shorter and lower voltage the spark.
So what are Points?
Points are tungsten-tipped electrodes that touch together and pull apart and they run on the back of distributor cam. These are what determines the dwell angle and cause the coil to fire.
The Points gap is what determines the Dwell. It does this in a very similar way to adjust the tappets. The bigger the gap the longer it takes for the cam to close up the gap. The smaller the gap the longer the Dwell.
We have left out another vital component in this picture. The Condensor - this is basically a capacitor, and it has an important role. As we mentioned, the points are made of tungsten. When they open and close there is a high powered arcing involved. This pits the points and wears them away. The Condensor acts as a buffer, reducing this shock thus increasing the Points life.
So what's what?
This picture shows the Distributor with the cap off:
This picture shows the same picture but with coloured circles:
Red Circle - Points
Yellow Circle - Condensor
Blue Circle - Nut to adjust the Points' gap
Green circle - Vacuum Advance Toothed Wheel
Now we know what happens we'd best get on with doing the job!
Of course as usual, the rest of the system needs to be operating properly, so HT leads held together with tape, eroded away caps, and rotor arms and plugs that have eroded so much the engine fits between the electrodes, are no use. Therefore make sure these other key components are in good condition.
What you need:
Feeler Gauges
7 and 11mm Spanner
Small Socket and Ratchet
Timing Light
19mm Spanner
Dwell Meter
You can do without the dwell meter and timing light but they make things much easier.
A side note: many of the cars with adjustable timing were made in the days of yore when fuel had lead in them. Lead increased the fuel's RON thus helped prevent pinking. Todays unleaded fuels are more volatile and thus they burn rather quickly. So if you are sorting out an old Renault 8 etc, use the standard figures for a base point only!
Figures vary for each engine, and in this case its for the 1397cc C1J engine.
The standard gap for the points is 0.4 mm, the dwell angle is 57+-3 degrees or 63% dwell (this is true for most though).
Ignition timing is 5 degrees advanced with the vacuum feed dissconnected and plugged or 10 degrees advanced with the vacuum advance in operation.
First thing to do is to pop the dizzy cap off so you can see the innards.
If you are replacing the Points and Condensor, then remove the small clip and unscrew the single screw that holds the Condensor to the Distributor's body. You can then lift the Points out of the Distributor along with the Condensor.
Fit them back in, then you need to adjust things, as follows.
Turn the engine via the crank pulley bolt until the cam fully opens the Points then see what the gap is. A 0.4mm feeler blade should be a sliding fit in here with some resistance. Pic shows the feeler gauge in the gap.
If you look on the bottom left of the pic you will see a shiny socket on the adjustment nut. To adjust the gap, screw it in to widen the gap and out to close it.
If the timing seemed okay beforehand start the car now, it should run nicely. If you have a dwell meter then connect it up. Here's my borrowed unit:
As you can see the dwell is at 36 degrees, which is better than it was. Before it was barely registering!
With more adjustment I got it where it's meant to be, about 56 degrees dwell.
This knocked the actual ignition timing out. So I had to rotate the Distributor again to bring the timing back to where it should be.
To advance the timing rotate the Distributor anti-clockwise, and clockwise to retard it. When the idle seems to be the strongest and most stable that should be the right timing, if you are using a strobe you can check it out. It may not be bang on what the manual says but if the car idles fine and accelerates fine then leave it as is.
The Vacuum Advance Toothed Wheel. This really shouldn't need to be tinkered with. In the red car mine was set at 4 clicks, when the timing was adjusted it seemed to far advanced. There was also evidence that it had been tinkered with in the past. So I backed it right off. There no real lack of go now but I will advance it a click at a time until I find the best compromise.
When I adjusted the timing and dwell to where it should be there was a serious missfire on part throttle around 2000rpm, when I backed off the toothed wheel this disappeared.
There are no hard, concrete-set rules for timing, as each engine is different. Set it to where the car feels best and it's not pinking.
The change in the red car since adjusting it from 2 degrees ATDC to roughly 8/9 degreees BTDC is quite remarkable, its transformed the car. Before it was dangerously slow now its quite pokey!
Linear Mode
