I recently replaced all of the lifters in my Magnum 5.2 with new ones from Sealed Power just for mileage sake. There was a light tick in the engine on the originals.

The new ones seem to have one lifter that does not stay pumped up when the car is off - it always goes clalalalack when I start it.

After the car is running, you can't hear it too well at idle, but it stays around all up and down the rev range, as if the lifter isn't pumping up the last little bit either.

I have made sure that all of the rocker pedestal bolts are tight and replaced the header gaskets on both sides. I also checked to make sure I don't have any loose or cracked spark plugs - nope. Neither of my header gaskets were blown out (I couldn't tell from the sound, when I blew out a gasket earlier it made a similar noise).

I tried adding some Marvels' Mystery Oil to the engine in case some lifter bore scuzz messed something up and this actually improved this behavior by a bit than when I first started, but I still can't get the tick to totally go away.

I also pulled all the pushrods back out to make sure they're clear end to end, which they are.

I'm suspicious that I may have a slightly bum rocker somewhere since I had a light tick somewhere in the heads/valley before I changed the lifters too. I have read about rockers occasionally being wear items on these motors.

Is there an easy way to check the rockers without a known good spare pair on hand? Is there anything else I could be missing? It is 100% definitely somewhere in the engine itself, not the tensioner or a plug wire arcing.

with you haveing pinned down the noisy lifter, you could replace it & as you know go thru the cam breakin procedure.

And you said the push rod ends look good...but are they straight? Did you roll them on a mirror after cleaning them?

Aha, I did not. I will check that next.

Well, all of the pushrods were straight. I think I may just have a slappy loose timing chain.

I've read that Magnums can develop a ticking noise from the timing chain getting loose enough to start slapping some piece of metal sticking out from the thrust plate or the inside of the timing cover and cause a ticking noise that sounds like a lifter or an exhaust leak.

When I started the motor after putting the rockers back on this time, there were a couple of lifters that needed to clacklacklack pump themselves back up, but then it was *QUIET* for several seconds until the tick started appearing again, which doesn't make sense to me for lifters.

actually I had a later hyd lifter /6 & the clacking would come and go (not sure how many,maybe all of em) cuz I never bothered to check it out (you cant kill a /6!) & the psi was plenty.

I haven't driven the car since this last check, but before this last garage session, driving around the tick really only seems to change between 500-1200rpm, otherwise it's the same all up and down the rev range (or at least up to 3000-something, I'm not going nuts until I have a better idea of what's up)

Actually, is it safe to run these motors/heads with a valve cover off to do the old screwdriver-stethoscope on the rocker pedestals? I haven't done that yet, that would sure tell me if it's an individual lifter or something else entirely.

It's "safe", but it'll get messy real quick.

Some years ago I build a 496" BB stroker. A number of lifters started collapsing when the engine was held at higher rpms for awhile.
Took a long time before they recovered.
Opened up, checked and cleaned the lifters 2 times and they still kept doing this.
Checked the oil for possible foaming but that didn't happen.
Could have been a engine block issue maybe, but at the time I was getting fed up with it and replaced them all with solid lifters which solved the problem.

More recently when I built my 360 engine I encountered a similar problem with certain lifters not staying primed and started ticking.
One lifter never pumped up and a couple of others collapsed when the engine was held at a higher rpm for awhile.
Again, here too I checked out all the lifters but found nothing wrong while the issue remained.
I modified the lifters to act like solids and the problem was gone.

Reading other people's similar stories and experiences online, it seems almost installing new hydraulic lifters are a crapshoot at best these days.
I'm currently at the point that I will never install hydraulic lifters anymore in an engine build if I have the choice.

I don't have the $ to switch to solid lifters and adjustable rockers, I wish I did.

I drove the car to and from the airport yesterday and the tick is extremely persistent at cruising + accel RPM, but I do have to say it is less noisy than it was earlier right after I finished swapping the lifters.

Could removing the rockers repeatedly possibly be helping with this? I.e. taking seat pressure off of the lifter.

The misbehaving lifter doesn't stay pumped up with the engine off (always clacklacklack on cold starts) and seems to have some last little smidge that it cannot pump up to at speed - it ticktickticks from 1200rpm -who knows, but now I can barely hear it at idle and sometimes it's just gone if I turn it down to like 550rpm.