I'm having a few problems with these lifters. Twice now one of or more lifters have collapsed. The first time it was just one lifter but after refitting the valve covers and starting the car it pumped back up after about 15 seconds. The second time it was two lifters, again I started the car and it sounded like one pumped up but the other refused. I've now got the lifters on the bench and one has collapsed. I've tried pumping the lifter up in a can of oil but it just won't. I can't take the lifter apart because of the link bar rivet. Any idea what I can do to get this lifter to pump up?

might be some debris in them. try cleaning them with brake kleen or solvent, blow them out & soak in oil. then try them. might be a bad lifter too.

I'm beginning to think it's just a bad lifter myself but two other lifters did the same thing and then started working as normal. I may have been running too much oil causing the oil to get aerated. I'll try some solvent tomorrow.

Found out why these Comp lifters started clattering on Sunday.
I couldn't completely disassemble them because the link bar rivet stops the plunger from being removed. I was able to remove the pushrod seat by pushing the plunger down far enough to lift the seat off. Under the pushrod seat there's an oil metering disc and as you can see from the picture, on these two lifters it had shattered into pieces. I also noticed that there was no check ball under the plunger, instead they use a steel disc as a check valve (cheaper). The smaller broken pieces of metering disc get forced under the plunger and trap the check valve open so the lifter won't stay pumped up. That's the case with the lifter on the left, the one on the right was still working but the rest of the metering disc was nowhere to be seen, obviously under the plunger just waiting to jam the check valve open. This was the third lifter to collapse, the other two started working again after running the engine for a while. Pieces of the shattered metering disc must have jammed the check valve open for a while and then worked they're way past the check valve to the bottom of the lifter.

Wonder who makes the Lunatis,Howard's or Bullets?

Lunati are Morels, Howards uses Morel and another private company out West, depending on what series lifter it is. Bullet is all Morel last I knew. Morel doesnt sell diect or retail, they only sell to dealers or wholesalers. They private label for a lot of other companies. A lifter is a lifter is a lifter however is NOT true. There are different versions and variations of Morels, so dont think that because they are $299.00 lifters , that they are the premium Morels.

The Morels, Cranes, and GS Products are the best out there. They all have an Ultra Pro series, and they are a must for serious engines....

How much RPM? What valve spring? Todd

Did a little research on the Morels. They offer 2 types of HR for BB Mopars. One is part# 5319 which is a street performance lifter with .700 dia wheel. The other is a #6074 and called a Pro lifter with a .810 dia wheel and they say no heavier than 5w40 oil can be useful. I found these at JohnCalliesinc.com . Cranes HR lifters look like they're about $790!

Here I go Somebody will disagree but this is what I have found after building numerous hemi and wedge engines with these and other lifters.
The 6000 rpm is fine, but that is where you need to keep it. No higher.
I understand that is the spring called for by Comp. Understand I am a Comp dealer and sell and use their stuff. However, I have found with the retro fit hyd roller setups they need more spring than that.That spring will not control the valve weight of a big Mopar engine. These extreme energy cams be it flat tappet or roller are super aggressive lift rates that combined with large valve weight equals valve float. Valve float will kill any valvetrain. I have invited Comp over to the shop and we can show them if they are interested. Most of the R/D on these cam profiles was done years ago. If they were formulated on a 2.08 1.74 valve and you are probably using larger stainless valves the weight went up but the springs did not. Hope that helps.
TOdd

The base Morel that everyone is selling should have no more than 140 on the seat and 350 open or the plunger has issues. That is not enough to keep heavy Mopar valve trains under control--remember that roller lifter weighs a Lot too! I have seen those float near 6000 RPM bad enough to kick out push rods and when I say float I mean they just totally go out of control. The better lifter will take up to 175 seat and 390 open max--this helps out a ton but there is no free ride--those lifters cost--Todd or Compwedge can give you the best first hand advice --listen to them, use the correct oil as directed by lifter mfg and take great care not to over rev.
Comps hyd roller lifters have been junk since first introduced and have caused many failures.

Pulled the roller cam today and fitted a cam I used in this engine some time ago, Comp XE290S. This time I fitted 1.6 rockers for .576/.595 lift. Idle is a bit rough but I took it for a good drive and it runs well. Engine sounds quieter too, always sounded noisy with the roller cam.