Troubleshooting my 1970 Ford Mustang

No. STOCK engine. New double roller timing gear. No roller valve train assemblies.

If you could round up a lab o’scope for a day you might could see something wrong examining the spark plug signals. Don’t need any fancy equipment beyond a working o’scope. I’ve done it by wrapping a thin wire 10 times around the center wire from the distributor, and hook it to the o’scope probe, one end to the probe ground, the other to the probe signal. I do the same for w/the trigger signal, only wrapping the wire around the number one spark plug wire. The current to the spark plug when it fires induces a voltage to the probe which allows you to see the spark plug signals lined up in a row, starting at number 1 and going through the whole firing order. You may see one or more of the plug signals dropping out as the rpm increases. This might happen for example if the distributor was worn out. Seems unlikely given that the engine worked fine before the lay-up, but pretty easy to do.

Check the firing order of the plug wires and be sure they are in the correct position on the distributor cap.
You might also want to be sure there isn’t any crossfire in the plug wires or distributor cap.

Thanks for getting back to me. I wish I were new to old muscle car engines but I’m not. It would make me feel less stupid for sure! Everything on the ignition has been replaced twice to include the switch itself. I thi I its covered in an earlier post. Thanks again. Its usually the simplest thing that gets you but I’ve tried to go through all that stuff 20 times over hoping I might have missed something.

Did you try the experiment i mentioned about inducing excess valve lash? Loosen those rockers till they make noise and see if she still blows back up the primaries. Easy to do… I’m interested to know what happens, shame you aren’t in a garage a few blocks away, I’d already have one valve cover off, LOL.

Boy I sure wish u were down the road! Haven’t had time yet. I’m at the lake for the weekend. I had the rockers loose before but on to adjust valves. Next week I’ll try to loosen them and see if it makes a difference. Fi gets crossed!

There was a no-start thread here recently where the poster was discussing and trying all sorts of alternatives, when the problem turned out they were using the wrong key, didn’t fit that car … lol …

Larry:

You mentioned a new cam, I think. Is it possible that the intake lobe for the misfiring cylinder was ground incorrectly? Too much lift, wrong begin lift angle, too much dwell? I have no idea how to fix that. Just throwing out the idea.

Someone else thought that there was a problem with a lifter. Maybe there’s a connection?

I hope you find the solution.When youdo, Post the result in ALL CAPS!EmojiEmoji

Frank Martinoli

No new cam Frank. Stock engine. Replaced valve seals, lifters and timing gear. All other internals are factory. Engine has 73,263 original miles.

I misunderstood. The thread is getting confusing.