1968 911 Sportomatic with no spark

[JT912]

Quick background. Car was sitting for many years before coming into my possession. Was running before we started restoration. The time has come to wrap things up and get her running. She turns over, but won't fire. Troubleshooting finds no spark. First steps included pulling a wire from a plug and then the HT coil lead led to finding no spark being generated from either location. Distributor is an 002 with new rotor, cap, points, and condensor. I've also installed a new Bosch coil. Using a Haynes manual I ran through their troubleshooting guide for conventional ignition systems. It went as follows: (i) Are points opening correctly? Yes. (ii)Check voltage across terminal 15. Should be at least 9 volts. Yes. 14.07 volts. (iii)check voltage at coil terminal 1, points closed-no volts,points open- reading on the meter. Questionable results here. I was getting a similar reading with points open and closed. The voltage reading was around 1.2v but would drop to around .6 volts when the fuel pump (Hardi) would trigger. (iii) With the ignition switched on check the voltage across the contact breaker points; points closed- no volts, points open- meter reads. Points open-no reading, then the condenser is faulty. With points closed, my meter read 0.000 and points open, meter read .015v. I also tested the coil (and two others I've got thinking even a new coil might be bad) and all three had resistance readings with were in line with what they should be. (iii) seams like it might be on to the problem, but I am not sure where to go from here. I've also attached a picture of where I've definately got power. Input is greatly appreciated.

[911quest]

Being a 68 are still using the cast iron distributor? If so its easy to get a faulty connection to the points with the old bolt that passes thru the distributor body....this would be the first thing I would check.

[JT912]

In browsing through Upfix, that bolt came up as a problem with a proposed solution of using a piece of aluminum foil wrapped over the insulator block. I'll check this connection tomorrow.
Thanks.

[edmayo]

The screw post through the distributor body can be a problem as mentioned above. Put one ohmmeter lead on the post and ground the other to the dist. body. With the points OPEN there should NOT be a circuit. Often the moveable point arm is installed against the body instead of installing the insulating strip first. Stoddard has rebuild kits for cast iron 356 distributors which will work on your cast iron distributor.

[JT912]

Thanks for the info. I've been troubleshooting this for quite awhile now. With both of your suggestions, and a chance finding of a solution in an old Upfixin, I was able to get spark and for the first time in over five years got the motor to fire. Once all the Marvel Mystery oil and age was blown out, the motor almost idles. Now time to work through dialing in the carbs. I did pull the bolt and re-install it and still got no spark so I tried the method in Upfixin. I have a new-found appreciation for aluminum foil.

[JT912]

This is the video of the honest first restart of this engine. Unfortunately this isn't a "it ran perfectly after 20 years" story, but not bad for having rebuilt the carbs, dizzy, and most other things on this motor. Now the fun continues.
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[Fritter]

Thanks for posting the video, very cool!

[JT912]

I guess I'd been watching too many of the Youtube video of "first" time starts where the engines idle smoothly after sitting for 20 years. This was my reality.

[Rich Lambert]

I guess I'd been watching too many of the Youtube video of "first" time starts where the engines idle smoothly after sitting for 20 years. This was my reality.

Much the same way my first start went. Congrats!

[edmayo]

JT, glad you got the problem solved and car running. Now, one more question, I notice you are running a resistor before the coil. Are you sure that is needed with that coil. The original coil did use a resistor which was bypassed during cranking by the relay on the relay board. Most new coils are designed to be wired without a dropping resistor. It is not terribly critical, as obviously the car will run either way. I was just curious if that coil did in fact need the resistor. If it doesn't you might get a slightly higher voltage at the spark plug by eliminating the resistor, if in fact it isn't required.