flat cam lobe

[burdar]

Working on the Challenger today, trying to check some things off my list.  I've got a "tick" on the #3 cylinder.  I listened with my stethoscope and it's NOT an exhaust leak.  You can't really hear it when you first start the car but as it warms up, you can start to hear the tick.  I pulled the valve cover and removed all the lifters on the drivers side.  They all look fine.  There are no signs of metal on metal contact.  I assume if a lobe was starting to go flat, there would be signs on the lifter right?  You wouldn't have a bad lobe and the lifter look fine?  Looking down through the holes in the head, I don't see anything out of the ordinary on the lobes but I'm only seeing a small section of them.  I might as well pull the other cover and have a look at that side too.

I thought I had a surge at cruise but I noticed a miss when I drove the car the other day.  It's not a dead miss but it's definitely not firing 100% all the time.  You can hear it skip a beat every couple seconds at idle.  When you hold it at 2000rpm it's not running as smooth as it should.  I haven't checked the plugs or vacuum leaks yet.  I don't see anything that would be causing the "tick" either.  The lifters on #3 are still pumped up and haven't bled down.  I'm going to go out and have a look at the plugs.

[Chryco Psycho]

There is no Maybe if a cam loses the lobe , metal eats metal the lifter would be badly ground down on the cam lobe face

[burdar]

Pulled the plugs on the drivers side.  #3 was not quite as dark as #1 or #5. The ceramic on #7 was still very white.  I pulled it out of the socket and the end was broken off.  I didn't think I put any side load on the plug when I removed it.  Maybe the end was cracked a little?  I doubt I'll be that lucky and a new plug fixes the miss.

[Chryco Psycho]

could well be the whole problem is one bad plug

[Strawdawg]

 I have heard a tick when I cracked a plug from the spark jumping

[roadman5312]

There is no Maybe if a cam loses the lobe , metal eats metal the lifter would be badly ground down on the cam lobe face

                                        And it don't take long. 

[burdar]

The passengers side all looked good too.  All the lifters are back in.  I'll button it back up tomorrow.  I don't know what the ticking is under the valve cover.  The springs are VERY close to the rocker arms but I don't see any evidence that they were touching.  Once it's back together, I'm going to unplug the vacuum hoses from the distributor, EGR and air cleaner canister and see if it runs better.

[roadman5312]

Any evidence of spring/retainer contact inside valve cover.  ?  I've had that on aftermarket covers .

[burdar]

I took apart the lifters on #3 and drained the oil out of them.  I didn't see anything strange so I put them back together.  After I started the car, they made a lot of noise for a few minutes until they quieted down.  I don't here the ticking anymore.

The car still ran really bad.  It was missing and shook horribly when the RPM's increased.  I talked to a machine shop about what I could try next...I was all out of ideas.  Since the car had been sitting a long time, they suggested putting new gas in it.  They said gas only lasts about 90 days any more.  I had stabilizer in it but it had been sitting a year and a half.  I siphoned out the tank and filled it with new gas.  No more missing and shaking.  I feel stupid for not thinking of it sooner but at least it was an easy fix.

I still have a surge at cruising speeds I need to figure out.  I disconnected the vacuum advance and the EGR valve to try and isolate the shaking problem.  The surge is still there.  One problem at a time...

[Strawdawg]

You looked into the carb when it is idling to make sure there is no gas dribbling into it?

Old gas not only runs badly, but, it can gum up carb passages and necessitate a rebuild.

When you think you have a cylinder that is misfiring, you can disconnect one plug wire at a time and note if the engine runs the same or misses worse.  If there is no change, then you have probably found a cylinder that is not firing right as it should run much worse with one plug disconnected.

If the car has been sitting, that is probably a fuel related problem, I would guess, but I would check the clearance in the distributor make sure it is where it should be as well as clean out any dust, etc that may be coating the inside of the cap.