'70 won't start with ignition shielding installed

[Kenneth H.]

All through the winter the engine turned over fine, but it just wouldn't start. So I called my mechanic about 6 weeks ago and made an appointment, and also set up a tow. To make it easier on him, and to make sure that the distributor ignition shielding didn't get damaged, I removed it before taking it in. I tried to start it once more before the tow arrived, and the engine started fine. I took it to the mechanic anyway, and had him take a look. At that time I didn't associate the removal of the shielding with the no start problem.

He adjusted the carburetor, verified that the ignition system was functioning properly and I brought it home. I took it out three weekends in a row and the engine started without issue. It was time to get it ready for a local show, so I reinstalled the shielding on the morning of the show. I then tried to start it so that I could get it out of the garage to clean it up, and it wouldn't start. It turned over just fine, but it wouldn't fire up. During the next two weeks I tried to start it numerous times, without success.

I made another appointment with the mechanic and the towing company for tomorrow morning, and just now removed the ignition shielding. I decided to try to start it and it kicked right over.

So the question is, is it possible that the shielding could be grounding some component or causing some other issue, has anyone else ever had a a problem like this, or do you think that this might just be a coincidence and that there is some other problem?

Added: The ignition shielding is the '70 early type box shielding.

[Kenneth B.]

Re: '70 won't start with ignition shielding installed

All through the winter the engine turned over fine, but it just wouldn't start. So I called my mechanic about 6 weeks ago and made an appointment, and also set up a tow. To make it easier on him, and to make sure that the distributor ignition shielding didn't get damaged, I removed it before taking it in. I tried to start it once more before the tow arrived, and the engine started fine. I took it to the mechanic anyway, and had him take a look. At that time I didn't associate the removal of the shielding with the no start problem.

He adjusted the carburetor, verified that the ignition system was functioning properly and I brought it home. I took it out three weekends in a row and the engine started without issue. It was time to get it ready for a local show, so I reinstalled the shielding on the morning of the show. I then tried to start it so that I could get it out of the garage to clean it up, and it wouldn't start. It turned over just fine, but it wouldn't fire up. During the next two weeks I tried to start it numerous times, without success.

I made another appointment with the mechanic and the towing company for tomorrow morning, and just now removed the ignition shielding. I decided to try to start it and it kicked right over.

So the question is, is it possible that the shielding could be grounding some component or causing some other issue, has anyone else ever had a a problem like this, or do you think that this might just be a coincidence and that there is some other problem?

Added: The ignition shielding is the '70 early type box shielding.

You need to put a piece of rubber under the top cover. Your coil wire is grounding out on the cover. I have had that problem with my 67'S
KEN

[D S.]

Re: '70 won't start with ignition shielding installed

On my '70 LS-5 I discovered that one of the braided ground wires was laying across one of the posts on my ignition coil.

[Dennis S.]

Re: '70 won't start with ignition shielding installed

You need to put a piece of rubber under the top cover. Your coil wire is grounding out on the cover. I have had that problem with my 67'S
KEN

Kenneth
The same thing happened to me. That plastic insulator under the cover does nothing, and a thin piece of rubber doesn't get the job done either. I ended up making some spacers (welded nuts on threads) that would allow more room for a thicker piece of rubber. When I am not at a car show, that shielding cover stays on a shelf in my garage. Just something else to add to the unreliability of a 42 year old car.
Dennis

[Timothy B.]

Re: '70 won't start with ignition shielding installed

Kenneth,

You may want to try a new coil wire from the coil to cap as others have mentioned it's shorting on the cover.

[Dennis S.]

Re: '70 won't start with ignition shielding installed

Kenneth,

You may want to try a new coil wire from the coil to cap as others have mentioned it's shorting on the cover.

Then again, does anybody sell just the dated repro coil wire, or do you have to buy the whole set again from Lectric Ltd?

[Patrick H.]

Re: '70 won't start with ignition shielding installed

Then again, does anybody sell just the dated repro coil wire, or do you have to buy the whole set again from Lectric Ltd?

I wouldn't worry about the date. You can get away with that short piece being from another set of wires or wherever.

[Richard T.]

Re: '70 won't start with ignition shielding installed

Ken: I agree with the other guys that some how the top cover is grounding the coil. I would check the coil wires for pinching when the cover and lower shielding is installed. My 70 350 has a clear plastic shield under the top cover where the coil comes up and the shielding is all original. On an early 70 there are four plastic rivets that show when the cover is in place. Maybe on latter cars a piece of thin rubber was used instead of the plastic but I do not know for sure.

[Kenneth H.]

Re: '70 won't start with ignition shielding installed

Thank you everyone, for the insight. After reading all of the replies, I'm sure that the shielding is my problem. I've haven't looked yet, but I was also wondering if it's possible that the hot wire coming from the ignition switch to the coil is somehow getting grounded by the shielding. I'll have him check that tomorrow.

That said, I'm guessing that the coil to distributor wire is the culprit. I do have a reproduction shield and I've often wondered what that plastic was for. Now I know. I'm going to give all of the responses to my mechanic and let him decide how to proceed. I'll let everyone know how it works out.

Thanks.