Petronix Distributor Conversion

[Fordchap]

I'm having issues keeping strong spark. I have an industrial truck 218 flathead in my '49 B1B. I replaced the coil, points, condenser, voltage regulator (yes I polarized!) and still no spark. It was running fine, took it to a glass place and when picking it up, would not start. Plenty of battery because it cranks. Thinking of a Petronix conversion but wonder if anyone has any experience to share. Good idea? I'm assuming that the original generator and voltage regulator design work well with the Petronix coil, module and distributor. I plan to leave it 6 V positive ground. Any thoughts, insights before I purchase the conversion? Many thanks! Pilot House Newbie!

[Don Coatney]

I suggest you find and fix your problem prior to installing anything new. Have you used a meter to find out where you are loosing power to your ignition system? Your shop manual has a chapter on both the distributor and electrical system. 

[Merle Coggins]

changing to an electronic ignition system, like the Petronix, will only fix the problem if the problem is within the distributor. You said that you already replaced all of those components without success, so replacing them with something different may not give you the results you want. Have you checked for voltage at the coil, or distributor? It could be a loss of power to the coil from the ign switch. Or it could be a short in the distributor keeping a constant ground for the coil. The points need to make and break the ground for the coil to discharge electricity through the cap/rotor and on to the spark plugs.

Two quick tests with a volt meter, or test light. First is with key in ON position, you should have 6 volts at the Negative terminal of the coil. If that checks out your next test is at the Positive terminal, or the terminal at the side of the distributor. These should have voltage when the points are open and no voltage (grounded) when the points are closed. A test light will blink on and off when cranking the engine. If you can't read voltage at this point the problem is within your distributor. Likely a shorted out wire or terminal.

[Fordchap]

Thanks very much Merle, very helpful. I'll check all of those items before I go drastic!

[RodFru2u]

Fordchap,

Did the little jumper wire fall out of breaker plate ?

[Don Coatney]

If the pictured wire is grounded nothing will work.

[Fordchap]

I'll make sure I check this. Thanks very much Don.

[iowa51]

Had problems with hard starting/weak spark a few months after my rebuilt engine was put in with a Pertronix unit that also cranked just fine. Ended up being a bad wire from the relay on the firewall to the coil. Had been spliced several times but taped over so I didn't see the "bad" spots plus with moving the wires around when taking the engine in/out added to the wire breakage problem. Try hot wiring from the battery directly to the coil (be careful) and see if it helps. New wire and no more problems, at least this problem anyways.

[Fordchap]

Thanks for the response. i found the problem, fried wire from the points to coil was grounding. I replaced it, fired right up!