RE: 1996 408 Magnum

Back in the fall, it ate a piece of metal. The resulting carnage was 2 bent valves and pushrods in #3, 2 wiped out cam lobes, a scarred combustion chamber, and a couple of nicks in the top of the piston. I replaced all the broken parts and had a machine shop clean up the cylinder head. I was able to clean up the top of the piston with emory cloth. I put it back together and it sounded like can of marbles. So I tore it apart again and this time, the #8 intake lifter broke (and remember its a roller lifter) and tore the new cam up. I'm willing to write that off as either a bad lifter or I installed the cam, rocker or valvespring in wrong.

So now Im on camshaft #3 with a brand new set of lifters. Now it sounds like marbles again and it sounds like the valvetrain but Im trying to rule it out. So now my plan is to pull the oil pan and inspect the rod, wrist pin and piston skirt.

Am I on the right track? I feel like after going through the valvetrain 3 times I should rule it out. Remember I have not looked at anything below the top of the piston but I listened to it with a mechanics stethoscope and it sounds like the battle rattle is coming from the top.

Have you tried running it, and pulling a plug wire on down the line to try and isolate a 'bad' cylinder???

I did that a long time ago, its holding compression in every cylinder except for when it first broke and the valves and pushrods were bent

Not to be redundant, but what you're saying is, your noise is there whether the cylinder(s) are firing, or not???

I'm pretty sure he was asking you to pull the wires to see if the sound changes not if it misses When you pull the wire there is no explosion in the cylinder therefore it will indicate where your noise is.
Gus

Yes it ticks whether the cylinder fires or not

Valve covers are usually easier to remove than oil pans. Just because the valve train is new don't mean it ain't broke so verify the easy stuff first. If it does turn out to be the bottom end, the covers had to come off anyway.

Kevin

this has an intermittent tapping, like it skips a tap on maybe on every 3 or 4 strokes.

Sounds like a broken valve spring to me,still enough pressure to keep the valve closed but not enough to keep it working right under working conditions
Gus

In the late 70's my 383 Fargo had a tick. Being as I knew it all, I took it around to many experts. Fuel pump push rod, push rods, rockers, nothing helped. Got mad one day, and when I pulled #3 piston, half the skirt hit the ground. Used piston and new rings, away I went, until next time. Maybe with the impact, something broke.

Have you tried an x-ray?

Bent rod?