Lifter\Rocker question

[cwestra]

So I'm stuck on why the car performs well if the rocker adjustment is so far off on that one rocker. NO backfiring or shaking. I really don't want to open a ditch here.

Could it be because that's an intake valve and not an exhaust valve? I heard that intake valves that are out of adjustment are more forgiving than exhaust valves? Is this true?

Can you try swapping this lifter with one of the other ones to see if the problem follows the lifter or stays with the valve?  I'm not suggesting running it that way but just for measurement purposes.  That may help pinpoint the source of the difference.

[jimynick]

Has anyone considered that in this day of lousy oil, that the problem MAY be a worn lobe on the cam that needs extra length to take up? Take a magnetic base dial indicator ($50-60 at Princess Auto) and check the push rod movement on the bank you're working on, on the type (intake or exhaust) that is the same as the one you're concerned about- they should be the same. There's a reason for this and I'd also check that the adjusting screws are all the same length as were the push rods. It's a stretch, but if all the former check out, put your indicator on the valve end of the rockers and see if one somehow got bent. Good luck!

[Cooter]

Sounds to me like you are hoping against hope it'll live like this and won't hurt anything...Nothing could be further from the truth..Yes, the engine will run like that right up until it pops..No warning, no buzzers, no little voice in the back seat saying "Hey Do something fast"..Nothing..You mentioned "Hard miles", well, how many times has this thing been over revved? how many times did that Mustang almost get by you and you downshifted in order to stay out front, even @6800 RPM's? Are you still running the "Good" oil? Or did you go to a roller cam in order to get around this? Roller cams need "Good" oil too due to the highj rate of spring pressure and load on the lifters.

Those Roller rockers are known for coming apart as are roller lifters on the street. The little "axles" and wheels on the lifters are wearing out under severe street use and high rate valve springs, and the rockers seem to keep having trouble at the fulcrum needle bearings for some reason..Not saying your rockers are bad, just saying. You need to get to the bottom of this because I hear this little ticking sound..Tick,tick,tick,Tick, BOOM!

[Challenger III]

You might take a shot and back it off a little at a time to see if your lifter pumps up. If someone wasn't paying attention, it could have been adjusted before it pumped up all the way. The lifter piston might be riding low in the lifter.

[oldkimmer]

.....So , let me get this straight..............u ask for advice.........but dont want to take it...................i sometimes dont get some ppl.......kim.............

[Chryco Psycho]

I would use a strong magnet & fish out the one lifter & replace it ...wait you are running a hyd roller , I would think that lifter collapsed

[Jesus H Chrysler]

My guess is a collapsed lifter.  With all the pushrods the same and assuming all the valve heights are the same that is the most logical answer.  You might want to pull the intake and peek at that lifter and cam lobe to see what's up.  If you're lucky the roller saved the lobe and you might be able to just drop a new lifter in there and continue to march.  Collapsed lifters do make noise and new lifters can still collapse thru manufacturing defects.  Somebody must have knowingly or unknowingly snugged this one down to cover it up?