A contact breaker (or “points”) is a type of electrical switch, and the term typically refers to the switching device found in the distributor of the ignition systems of spark-ignition internal combustion engines.
Points. Ignition points are a set of electrical contacts that switch the coil on and off at the proper time. The points are opened and closed by the mechanical action of the distributor shaft lobes pushing on them. The points have a tough job, switching up to eight amps of current many times per second at highway speed …
Test for continuity between the block and the stationary point attached to the distributor plate. Rotate the engine until the points are closed. Use the multi-meter to test for a good connection between the points. A slight gap when the points are supposed to be closed will keep your machine from running.
The usual causes for pitted or burned points are setting the points too close or having a bad condenser. I assume you have replaced both the condenser and the points, so double check the gap on the points. Or even better, use a dwell meter if you can find one.
They’re used constantly – every time your car is cranked and then the entire time the engine runs. This puts a lot of wear and tear on them (hence the reason better, more durable ignition systems have been created for newer cars). In general, you can expect your points and condenser to last around 15,000 miles or so.
As they close, current from the ignition switch flows through the contacts into the coil’s primary windings and then off to ground. … All that current flowing across the points doesn’t like to stop suddenly, and can initiate a small arc, which eventually erodes the tungsten contacts.
If the spark is a big fat one, then the condenser is bad and needs to be replaced. 2. If no spark is visible, check to see if the points or wires are shorting to ground either at the points or at the primary terminal screw going through the housing.
Should points be open or closed at TDC? Theoretically, the points should be just in the process of going from closed to open at #1 TDC. … if you watch the points while you rotate the distributor body, you will see that you can make the points open OR close just be rotating the housing.
Points shouldn’t spark when the engine is running but they might while you’re working on it. The points are the grounding circuit for the primary side of the ignition coil. If the secondary side is not completed – spark plugs in and hooked up, (make sure the plug leads are good) you can get a spark across the points.
Weak spark is often the result of a bad condenser (and it’s a cheap part to replace). If you see higher resistance here, then you need to clean and check the connections and the circuit path to ground through the points. … Also check resistance between the distributor body and the engine block.
In simple terms, the ballast resistor in a Mopar limits the amperage, or current flow, through the coil while the engine is running, thereby extending the life of the coil and breaker points of the distributor.
Re: What is the effect of the points gap being too large? Too wide a point gap decreases the dwell angle. This does not give the coil sufficient time to charge, resulting in a weak spark. It also slightly retards the timing.
This is an older style of ignition system that uses points, a distributor, and an external coil. … In an electronic system, you still have a distributor, but the points have been replaced with a pickup coil, and there’s an electronic ignition control module.
Turn the key ON and crank the engine. Using a feeler gauge to get close, adjust the points to the desired setting according to dwell readings and tighten the points. Crank it again to be sure the dwell angle is still correct. You can now go on to set your timing.
If points are bad, the engine could experience multiple problems. Bad point connections cause engine overrun, timing issues, speed missing and causes the engine to misfire or fail to start. Look closely at the surface of contact points. Check for corrosion or degradation.
Turn off the vehicle and spray the spark plug wires and the inside and outside of your distributor cap with WD-40. … Using WD-40 to repel water from spark plugs, distributors, alternators, and batteries is a good way to prevent corrosion and keep moisture away.
To get them to be good enough to use for a long time, you can file them. If you file a slight radius on the contacts, that might be better than filing them flat.
Replacing the distributor cap and rotor at the same time should be completed every 50,000 miles, regardless of whether or not they are damaged. If your vehicle does not put on a lot of miles every year, it’s also a good idea to replace them every three years.
A wider gap will advance the timing. The sooner they open the wider the gap will be. As you increase the gap, the dwell angle will decrease because the points will open earlier. The spark occurs when the points open, hence increased spark timing.
Any condenser of the same value will work. They are indifferent to voltage but the capacitance (microfarads) should be the same or at least close. They aren’t that accurate from new. If the condenser is perfect your points won’t burn.
Once the top dead center timing mark is lined up with the marker on the engine, the motor should now be at top dead center. To verify, shine the flashlight down into the spark plug hole. You should be able to see the top of the piston clearly near the top of the cylinder.
It’s up to you. Both valves should be closed if it’s TDC at the end of the compression stroke. If it’s TDC at the end of the exhaust stroke, you should be in the valve overlap zone, with the intake valve partially open and on its way to opening fully, and the exhaust valve partially open on its way to closing.
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