Dead Cylinder help me diagnose.

[Internexus]

So I noted yesterday that I had a couple dead cylinders when pulling wires from the distributor. This is a 289 that I just got running monday after it sat for 6 years. Anyways decided to change the plugs to see if that would cure the situation. One of the plugs had only a few thousandths for a gap, all the plugs looked great except one, it was covered in carbon.

So after getting it all back together the one with the closed gap came to life so I am running on 7 cylinders now. The one covered in soot I thought about, I changed the exhaust gaskets because I thought I had an exhaust leak but now after startin it up the noise is still there so I am certain the valve train has an issue going on. I believe it is the intake side of cylinder 6 that is not working. Would this be the front or back valve on the head? Is there a particular item in the valve train that would fail?

Obviously I have only a few options, a rocker, valve spring, lifter, pushrod. I am kinda worried about it being a lifter that is collapsed and I may not be able to get it out? Does anyone have any ideas or do you feel I am on the right track with this? I won't be able to get to it for a day or two sadly.

 

[69gmachine]

Pull the vc off and do a visual inspection of the rocker, valve spring and pushrod. You'll need to pull the pushrod out and check it for straightness by rolling it on a flat surface.

There are many other potential sources of your problem however. You could have a worn or broken piston ring allowing oil to enter the combustion chamber, or a burnt valve. Did water ever get in the cylinder? If so, it could have rusted up the bore and ruined the rings when you started it up. Do a compression check at minimum, and if you can get access to a leakdown gage, use that to assess the health of the cylinder in question.

A collapsed lifter means the plunger is not pumping up to take up the slack in valve lash. It won't have any effect on being able to remove it. If the lash was set properly before the plunger collapsed, you'll have a large valve lash that will cause a ticking noise. If the lash was set with the plunger collapsed, the valve won't seat once it's pressurized and that cylinder won't fire. However, if that's the only problem, the spark plug won't be sooty because without compression it won't light off.

You didn't give us much to go on. You're going to have to just dive in and start checking things. Make note of anything that looks wrong, like exhaust or oil in the intake.