VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 235 engine problems

Many times I have no help . I have a 55 chevy 2nd series truck with a 235 engine . I am not able to start the engine and it is not a fuel problem . How can I test the coil or points without a 2nd person here to help me ? Any solution ?

Mark, You can check the coil for continuety and for a short with a Ohmmeter. then check the (+) coillead for battery voltage with the ignition on, I check the (-)lead with a voltmeter while cranking the needle should swing up and down as the points open and close, then be sure the timing gear on the camshaft is moving the valve rockers up and down and rotating the distributor rotor, Check out the breaker point gap, rotor and distributor cap. I use a heavy duty under the hood starter switch, clipped to the battery and to the solenoid to turn the engine with the starter, I clamp a new sparkplug to the engine (good ground) with vice grip pliers so that I can see the electrode end, and connect the #1 plug wire to the new spark plug, with a fully charged battery crank the engine in a darkened garage and watch for a spark at the new plug. That is my way....


You can probably also hook up a timing light to the battery and the #1 sparkplug wire and crank the engine and pull the trigger on the timing light, if everything is hunky dorey it should light on and off.

You can check the coil and points by removing the coil lead from the distributor cap and holding. Take the cap off the distributor, hold the end of the coil wire near a good ground (make sure to insulate yourself from the wire or it will light you up) and then use a screwdriver to open and close the points (or if the points are open then use screwdriver to short across the points. Arm to arm is ok for a test). Oh ya, works best with the ignition switch ON. Note the length that the spark will jump. With good coil it should be at least 1/4". You should also hear a sharp "snap" sound.

If you don't get a spark when shorting the points. Then check to make sure you have current to the points. Could be ignition switch, broken wire, short circuit. If you don't get a good spark from the coil wire then substitute another coil.

Once you get a strong spark from the coil wire to ground then put everything back together and check a spark plug or plug wire for spark. It requires turning the engine over in most cases. However if your distributor has an advance (or retard) mechanism that you can operate from outside (by moving a lever, rotating the distributor body or ??) you can set it up to test without rotating the engine. Rotate the engine with the distributor cap removed until the points are just open or just closed. Rocking in gear, using the fan, large screwdriver levering the flywheel teeth or ??? are methods that can be used. Then operate the advance to open or close the points. Once that is done then install the cap making sure that the rotor points to a plug wire terminal and check that spark plug wire to ground. If that produces a large spark (same as the coil) then install a plug and test again. You should get a spark that you can hear if not see.

There are other ways too. One is to make sure the points are closed and the rotor is pointed to a plug wire terminal. Take off the negative coil lead and touch it to the coil to simulate the points opening and closing. Again the ignition switch needs to be ON!

Good luck!