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| Joined: | 03-12-2005 |
| Location: | Kingman, Arizona USA |
| Posts: | 532 |
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The mechanical cam timing sounds correct, as does the stated static ignition timing. And while problems in these areas might prevent an engine from running, they would not prevent the ignition system from working.
The stated 0.035" spark plug gap is too big. And while a good ignition system will often give a spark across such a large gap, the time to experiment is after everything else is working fine. Initially, at least, the correct gap is 0.025" with Strombergs and 0.023" with Dellortos.
Installation of a new Pertronix coil was mentioned. If this is the type of coil that requires an external ballast, then it is hooked up exactly as is the stock coil, with the ballast resistor being connected between coil and ignition switch and the ballast bypass wiring (from the starter solenoid) also connected. Note that a coil that requires an external ballast, if run without one, WILL overheat and may fail in a very short period of time, giving precisely the symptoms mentioned. However, the substitute coil speaks against this as the problem. However, with sufficient bad luck, the current through the coil could have been so high that the switching transistor inside the Pertronix module was destroyed.
On the other hand, if the coil contains an internal ballast, then the wire from the ignition switch connects directly to coil (+) and the ballast and the ballast bypass wiring from the starter solenoid are ignored. A coil with an internal ballast, that is wired up with an external ballast as well, may not produce enough high voltage to create a spark across a wide spark plug gap.
Deal with the issues above and see if the car runs. If not, then the problem sounds like the basic 'No Spark'. When that occurs, I usually suggest the following:
1. Manually rotate the engine so that the distributor rotor aligns with one of the spark plug turrets on the distributor cap. Do not guess, do not assume, pop the cap, take a look, and make SURE. Check a second time as you put the distributor cap back on. This is particularly important in a JH as many if not most of its ignition problems involve incorrect ignition timing of one form or another.
2. Trace the high voltage wire from the turret to which the rotor points, to the associated spark plug. Disconnect this high voltage wire from this spark plug, and connect it instead to a test spark plug having the correct gap. Ensure that the body of the spark plug is in firm contact with the engine block, and that it is possible to see the spark plug electrodes.
3. Unplug the wire attached to the coil (-) terminal. Place the ignition switch to the RUN position and verify the presence of +12 volts on the coil (+) terminal.
4. Repeatedly make and unmake a connection between the coil (-) terminal and chassis ground using a test wire, screwdriver blade, etc. Each time the connection is unmade, there should be a bright blue spark between the electrodes of the test spark plug.
4a. If so, then the basic problem is either incorrect ignition timing, some sort of mechanical problem in the distributor or its drive, defective points / condenser / Pertronix, or (very rarely) a coil whose high voltage output is so low that it can make a spark in air but not in a cylinder under compression.
4b. If not, the problem is a defective coil, a defective high voltage wire between coil and distributor or between distributor and spark plug, or a defective distributor cap or rotor.
4c. In either case, you'll have a direction in which to proceed.
To verify Pertronix operation, connect the coil wiring as appropriate, then rotate the engine and verify that the voltage on the coil (-) terminal goes from zero volts to +12 volts and back to zero twice per engine revolution, just as it would if points were installed and were opening and closing. If not, either there is something wrong with the Pertronix or the distributor shaft isn't turning.