Tecb Tip
Do You Have Spark?
Let’s get started.
Check spark directly at the plug
Get your spark tester ready.
Connect plug wire to tester.
Hold the threaded metal portion firmly against clean engine metal.
Crank the engine.
You want a strong, blue/white, snappy spark that consistently jumps the gap.
A weak yellow/orange spark is suspicious.
Check every plug wire
Make sure the terminals inside the distributor cap and at the plugs are clean and making good contact.
Test the spark directly from the coil
Remove the center high-tension wire from the distributor cap.
Hold its terminal about 1/4 inch from a good engine ground.
Crank the engine.
You should get a strong, regular spark from the coil wire.
Strong coil spark but weak/no plug spark = distributor cap, rotor, wires, or connections.
Weak/no coil spark = investigate the coil, points, condenser, primary wiring, or ignition switch.
Check the points
With the distributor cap off:
Crank the engine and verify the points actually open and close.
When they open, you should see a small spark at the points—not a huge arc.
Check the point gap against the Crosley specification.
Make sure the points are clean and not oxidized.
Verify the distributor's moving point plate isn't loose.
Check condenser
A bad condenser can give you a weak or erratic spark even though the system appears to be functioning.
Excessive arcing across the points is a clue.
Since you've already replaced the condenser on your Crosley, I wouldn't automatically replace it again, but it remains something to double-check.
If you replace the condenser on your Crosley, use the same screw that secured it. If not, make sure the screw is short enough to ensure it doesn’t interfere with the distributor.
Check the distributor rotor
This is particularly important on your Crosley.
Make sure the rotor turns when the engine is cranked.
Verify it isn't cracked, burned, or loose.
Confirm the rotor is actually pointing toward the appropriate cap terminal when that cylinder fires.
Verify firing order
Even with four excellent sparks, the engine won't run if the wires are installed in the wrong order.
Confirm the Crosley's specified firing order.
Trace each wire physically from the distributor cap to its cylinder.
Don't rely solely on how the wires "look" like they're arranged.
Note: Crosley distributors turn counterclockwise.
Verify ignition timing
This is a separate issue from simply having spark.
You can have excellent spark but have it occurring at the wrong time.
Since you've already been working with static timing on your Crosley, I'd verify:
#1 is actually at compression TDC.
The distributor rotor is pointing to #1.
The points are opening at the specified advance.
The timing mark you're using really corresponds to #1 compression TDC.
In summary, remember you are primarily checking for spark. A $5.00 spark tester investment (Harbor Freight, Amazon, Wal-Mart, etc.) is highly worth it. Also, in general, you are checking for electrical shorts throughout the ignition system.
For the next several Tech Tips, we are going to focus on specific areas based on our earlier general recommendations. We will not address every possible check but will focus on very practical areas especially common to Crosleys.