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BASIC ENGINE SET UP
For the best reult all the components of the ignition system must be in good working order e.g. Plugs, gaps, distributor cap, plug leads, rotor arm, condenser and distributor spindle bearing etc.
If at all possible do a compression check, that gives a good idea of the health of the engine, bore, rings and valves.
Get the engine thoroughly warm – at least 10 mins running.
Remove all four spark plugs
Disconnect coil from battery
Prop accelerator pedal down with a broom handle (to open the throttle)
Screw gauge into each cylinder in turn and measure highest pressure reached on starter (may take 5 – 10 turns)
A steady cranking speed is needed, if battery is low results will tail off
After the ‘dry’ test introduce a teaspoon of engine oil into cylinder and repeat.
If adding oil doesn’t make a difference suspect valve problems.
Typical level for a road-going car & perfectly OK: 80-90 PSI (variation is not only wear but head type, skimming, valve overlap etc.)
A “fault” is indicated if variation between two cylinders is over 10%.
NOTE: It’s well worth checking your tappet clearances from time to time!
This is the result of a test I carried out, this indicates that cylinder number 1 is losing compression past the the rings.
From experience, the following method to set the static engine timing is easy, quick and accurate enough to get you running and does not involve exposing the flywheel.
Remove No1 sparking plug (nearest the radiator) and set cylinder No1 on compression by rotating the engine and placing a finger over the plug hole and feel for compression developing this is easier with the all plugs removed.
Check the contact points are 12 thou’ (0.012”).
Set No1 piston exactly at top-dead-centre using a thin wooden dowel (to prevent any damage to the piston crown) inserted through the plug hole. PHOTO You can buy a screw in purpose made tool, but they don’t work in our engine as being a side valve the piston is not directly under the plug hole.
To find TDC rock the crank either side then ‘middle’ it to find the center.
Connect a low wattage lamp between the low tension terminal on the side of the distributor and a convenient earth point. If the ignition is now switched-on and the fibre heel is mid way between cam lobes (i.e. the points are closed) – the test lamp will remain unlit. PHOTO
With the ignition still switched-on, slacken the clamp at the base of the distributor body and very slowly turn the body anti-clockwise whilst observing the test lamp. When the cam approaches the fibre heel, the points will start to open and the test lamp will light immediately the points separate. It is useful to repeat this several times to determine the correct static timing position. Having done this – tighten the distributor retaining clamp bolt.
The engine should now start-up and run reasonably well and the final fine adjustments should be done with the engine running at fast tick-over by one of the following two methods:
If you are old enough to have worked on engines before the advent of electronic tuning devices (i.e. when sweets were on ration!) you will be able to make fine timing adjustments by simply listening to the sound of the engine. This is impossible to explain in writing but can be learned by years of practice.
Alternatively make a series fine timing adjustments by trial and error.
Make SMALL rotational adjustments to the distributor and carry-out a road test to consider acceleration, maximum speed and top gear hill climbing, without ignition knock.
Note – to advance the timing, rotate the distributor anti-clockwise and of course clockwise to retard. Try to reach a compromise between best performance and a smooth engine note. An over advanced engines will sound harsh, feel rough and vibrate under load. An over retarded engines will be noticeably down on power, can sound rough and may run rather hot.
Note: Correct ignition timing may lead to excessive noise if the engine main bearings are worn, in which case it may be desirable to run the engine slightly retarded.
If the distributor has been removed, replace it in the correct position with the flat side of the body facing mid-way between cylinders 1 and 2.
When entering the distributor into the dynamo to engage the skew gears – make sure the fibre heel on the contact points is mid-way between cam lobes.