Car Ignition Timing Adjust for carburettor Classic cars
Engine timing is to be set at a specific degree in relation to the crankshaft of the engine. If this timing becomes mis-aligned it can cause low power, poor gas mileage, engine detonation (pinging) andbackfiring. To check the engine timing locate the number one cylinder of the engine. This number one cylinder will be the forward most cylinder of the engine. On straight 4 and 6 cylinders engines it is pretty obvious, but on "V" style of engines like the V8 it is a little more tricky. The cylinders heads on every "V" style of engine are offset from one to the other.
One cylinder head is more forward than the other. The most forward cylinder head is the side of the engine where the number one cylinder is located. The forward most cylinder is the number one cylinder. Next, locate the crankshaft timing marks, most engines timing marks are at the front of the engine on the harmonic balancer. Near the balancer there is a small pointer or scale to align the balancer mark to. When the engine is running this gauge or pointer should align with the mark on the balancer.
Strobe timing usually has to be carried out while the engine is running at a certain speed, usually tickover speed. This varies from car to car, so check the manual.
Turn on the engine and look at the rev counter (tachometer) to make sure that the engine speed is correct. If the speed needs to be altered you can do this by adjusting the idling screw on a carburettor car.Aim the strobe light at the timing marks The light flashes very brefly every time a spark voltage flows to the chosen cylinder. so in that instant everything seems to be stationary. This is because each time it flashes the moving mark has rotated by two turns, but since the spark comes at exactly the same instant in the cycle, the mark appears not to have moved at all, The other moving parts of the engine have an odd appearance.
The fan and generator pulley may seem to be moving quite slowly often backwards. If the flashes are bright or the surroundings are dark this can be very misleading and though you know the fan is really moving quickly you can
Altering engine speed Engine speed (rpm) is critical when setting the ignition timing with a strobe. You can alter this if it is wrong by adjusting the idling screw. This is fixed to the side of the carburettor close to the point where the accelerator cable or rod is attached. To help you locate the idling screw, have someone press down on the accelerator pedal while you look carefully at the carburettor.
Turn the screw clock- wise to speed up the engine. anti- clockwise to slow it down. Always return the engine to its normal tickover speed setting when you have finished. timing position, If the timing is set wrongly. loosen the pinch bolt holding the distributor In and turn the body in the opposite direction to that of the rotor until the correct timing mark lines up with the marker. Then retighten the pinch bolt just enough to make sure that there is no chance of the distributor movlng.
The ignition timing should now be correctly adjusted Continue to run the engine for a short while and check with the strobe light that the marks still coincide. If a Vernier gauge is fitted you can use it to make adjustments finer than those you can make manually. with the distributor body clamp, Point the strobe at the timing marks and turn the screw gauge slowly backwards and forwards until you find the precise spot where the stationary marker lines up with the correct advance mark. Turn off the engine and unclip the strobe light. Finally. replace the vacuum advance pipe.