missfire in the three hole! help?

[HLS30-51947]

my 72 is breathing new life after being stored for the last six years,forgot how much I love my Z! Anyways evey thing seems too be working good except for a miss in three hole. I have been through the fireing order many times, run the valves both hot and cold and I can't get it to go away. It sounds like a very poorly adjusted rocker tick tick tick tick, when I pull the plug wire off it stops making that awful noise and definatly draws down the engine. I checked the plug wires,there all good.I checked the plug in the three hole its also fine. any ideas or suggestions would be greatly appreciated. Arnie from spring field are you coming too Idaho any time soon I could definatly use some of your zwizdom right about now! thanks Brock from Boise

[Arne]

Sorry, no plans to come to Idaho any time soon, Brock.

But if I'm understanding your description, your problem is not an actual miss, but a loud ticking noise that goes away when you take away the spark. Since the noise stops then, and also because the engine slows down, I'm pretty certain that the cylinder IS firing. I'm also afraid that you have more serious problems in the lower end - perhaps a bad rod bearing or possibly a wrist pin. But more likely a rod bearing. The noise goes away when the spark is pulled because that piston is then coasting.

[HLS30-51947]

Thanks for the reply. I pulled the pan and checked the rod/main bearings they both look great. I'm starting to think its either the wrist pin or valve. Thanks again. Off the subject my older brother just got a great job in Roseburg and will be moving there soon, he says Its A beautiful area, I will have to check it out someday! got to run,later..

[bloxman]

just on the off chance, 'cause everything else is sounding so good...

How about an exhaust manifold leak.

I had an experience once where the ticking increased with rpm and the ticking got louder as the engime warmed up... Sounded exactly like bad tappets .

Turns out the previous owner of my car had replaced the exhaust manifold gasket and never tightened it really passed hand tight.

As soon as I tightened everything up the engine was a cracker!

Bloxman

[HLS30-51947]

thanks Bloxman I will check them out. I just replaced the manifold to exhaust gasket but i never checked the manifold to head connection. I would also like to thank the people who maintane this web site . I freakin love it..... Brock in Boise