The one lifter/pushrod/rocker out of the 16 that is profusely oiling, I opened up the lifter thinking maybe the metering disc is missing & it was there which tells me that a flat metering plate with no holes in it IS correct like was priorly posted that these are also listed for an AMC application, so I buttoned it back up & reinstalled the lifter/pushrod/rocker assy (just like it was) & preoiled again & now it is oiling just a hair like the 15 others & not profusely like it did before & all I did was dissassemble/reassemble it ???! so as advised prior I turned the crank a bit & preoiled & turned it more & preoiled & repeated this several more turns/preoiling & each time all lifters are bleeding just a hair of oil (not near enough). Today I pulled ALL the rockers/pushrods & preoiled & all the same, just a very very slight bit of flow out of the lifter tops Sooo I dropped another set of hyd lifters that have minimal run time & they gushed oil then while I was at it I dropped in another set of used lifters with minimal run time & they barely bled like the very first set. ALL (3) lifter sets look identical on the outside as far as oil band groove height/width/hole & have a thin circular perimeter groove near the top of the lifter (served no running purpose I know of) but I am puttin everything out there. I'm thinking to get a new set of Melling JB2011 lifters tomorrow. Any thoughts on what is going on here AND is there a way to check the convex face to see if the slightly used set that oils profusely IS useable AND if this a too risky of a move to reuse lifters (even with minimal run time). Thank you for your time (& patience).

Sorry to have to break it to you, but what's going on is you. You inspect and think the heck out of things when maybe you should just plop'em in and go. Even in something as generic as a 2011 lifter (and they are generic, the one size fits all for basically every 0.904" hydraulic lifter) there are differences between manufacturers. They are subtle differences, like tiny holes around the perimeter of the metering disk, or not.

BTW I know that all 0.904 lifters aren't the same, but the 2011 is what you'll get in the majority of cases at a parts store. Eliminating part numbers is a way to decrease cost.

Now on to your barely used lifters: They're probably OK. The way to tell if they're convex is to hold two lifters foot to foot and see if they will rock slightly. Or put one on a perfectly flat surface and do the same test.
Back in the day there were some GM lifters that were manufactured with too coarse a surface on the lifter foot and we were told by Chevrolet Racing to chuck them in a lathe and lightly sand the bottom with 1000 grit paper. The grit number may not be accurate, my memory isn't sharp on that point. Another thing to look for on your barely used lifter is if any wear pattern visible is circular and concentric to the lifter body. That would be good. Any straight line from edge to edge would be bad.
It usually doesn't take a lifter long to wear once it starts. It isn't very gradual, more like abrupt.
The load the lifter carries is the second area of concern. Stock springs run like 80 - 90 lb load on the seat. This makes the pressure between lifter and lobe pretty low. Pressure is load over area, measured in psi. Seat load and open load are the two largest factors governed by the valvesprings. The cam designer controls the last factor, acceleration of the lifter. When the lifter is lifted off the base circle, it not only has the spring load but it has the load of accelerating the valvetrain. Greater lifter acceleration is the key to power and the key to wear.

Adding this together we find that if put in a stock setting your lightly used lifters will almost certainly work fine as is. The more aggressive a cam you use, the higher spring loads and inertial loads on the interface between lifter and lobe will result in higher contact pressures. So as cam gets hotter, the risk goes up. To reduce the risk you check lifter bottoms and maybe put a new slightly rough surface on them with 1000 grit paper. If you are going full bore on the cam, Delta and others will resurface the lifter ends for a small fee.

Finally, make sure the lifters rotate as the cam rotates.

Best Regards,
R.

Dog it is an accepted caveat not to use used lifters on a new cam so my thinking was straight here (to check if the very minimum (10 minutes) run time is OK or not OK). I was on it today & the one set of slightly used lifters (that oiled) rocked held back to back, some still had circular circles so I put em in on the cam lobes & with no pushrods they flowed a "fair" amt of oil out of the pushrod cup holes so I figured woo hoo I am good! (finally) Then I added the pushrods/rockers & preoiled again & it immediately reached 80 lbs then about 2 seconds later I could see oil flowing like a river down both valley sides (from the valvetrains) & the psi dropped to ~25 or so & fluttering & I could hear the sucking at the pickup like it was running out of oil in the sump (4qt pan/hi vol pump/filter) & I had poured in 5 qts. The valve train is flowing a torrent of oil, [ Moparts Family Site - Keep it Friendly ]. these are stock MP replacement magnum rockers & the MP pushrods for this conversion & the aforementioned lifters. Help... I am hitting the wall on this deal! What am I missing/not seeing? I grasp the slightly used lifters/new cam deal but what orifice or orifices is oversized/mismatched to be flowing that kind of flow?

I tried several ways to plug one pushrod end with something then drill it out to .040" to no avail. I am gonna finalize what pushrod length I need & call Smith Bro & go ahead & spring for a set, 5/16 with .040 orifice. I will holler how it oils with em in place.

RR I would think you just need the lifters for the magnum eng that used pushrod oiling of course. I mean I don't know for sure but my guess is the lifters for the older 318 to 360 had no holes in the disc since they oiled through the head to the rocker shaft but the magnum lifters should have the oil holes in the disc since they oil that way. I cant remember what year the magnum went to the roller cam but I do remember some years the 318 to 360 in trucks I believe used flat tappet cams while the cars of the same year used roller cams. I had a tech put flat tappet lifters on a roller cam once when parts gave him the wrong lifters.

I would think the older LA eng and newer magnum engines take a different # lifter ? But that said I also noticed on my 440/493 flat tappet solid lifters I used they all were open at the top and had oil holes in the sides of them like they can be used for pushrod oiling. My lifters are the ones that have the small hole in the bottom to put oil on the cam lobe all the time. My pushrods are solid and block the upper hole in my lifters as I use the stock oiling up through the heads to my rocker shafts. So my pushrod blocks the oil that could come out the top because my eng carries from 40 to 80 psi all the time. So I would think if the flat tappet lifters for the LA and magnum engines did have the same part # then they should all have the oiling holes in the disc since the solid pushrods in the LA engines would block the oil at the top of the lifter ? But I never checked them to find out. I would guess you asked if the magnum and LA engines call for a different part # lifter ? Ron

I called Smith bros & they have oiling orifices of .020/.030/.040 & they suggested I call Hughes to pin down which one I should order & Dave said that he had never heard of this issue (which was disheartening!). I told him that it was an iron 360 block with EQ mag heads & the MP stuff (.104" orifice pushrods/thin guide plates/"sled" rockers) and a Melling hi vol pump (I was assuming). I did notice the feed hole in the 2 lifter sets, one set is way smaller than the other set (I did not measure em). Preoiling with a healthy 1/2 HF drill I get 80 psi in a split second then within another second or so the gauge drops to ~25 ish & is fluttering & the rockers (both) are being FLOODED with oil & he said to take the HV pump out of there & he asked me if I primed it with some grease (which ostensibly might have jammed the bypass closed I'm thinking he is thinking) & I replied no. He said restricting the pushrods wouldn't fix it as the psi would cause a problem elsewhere so I just came in from the garage & pulled the pan & to my dismay it is a Melling m72, not a hi vol... It did have a 1/2 pickup (housing drilled/tapped for that) but that is on the supply side which I wouldn't think would have a bearing on this. I just called him back & he has closed early for Friday so that is where I am at. The gauge said 80 & it is a 5 dollar mechanical cheapie but the rockers are flooding so there is no indication that it ain't right. This is where I am at so far. Any thoughts? WHAT am I missing! EDIT cam is hyd flat tappet MORE EDIT & when the gauge is fluttering at ~25 I can hear the pickup sucking/gurgling. (VC's & intake are off).

Today I preoiled with another m72 pump/std 3/8 pickup & got NO flow up top with the new lifters. put in a prior set of slightly used ones & it gushed up top (like before). I tried another set of slightly used lifters & NO flow up top. All (3) sets appear externally to be the same (not sure of the brand but I think Melling on all (3). the oil holes in the recessed band on all (3) sets is .094. I'm lost! Any thoughts? EDIT .104" pushrod oiling orifice (if that is critical).

This may or may not tell you anything, but it’s a pretty painless test.

Take one of the lifters that’s flowing a lot of oil, take it apart, completely clean it out so it’s basically dry....... put it back together.
Install it in a lifter bore where the cam is on the base circle........ prime engine.
See how long it takes to get oil flowing out of it like it was before.

Dwayne I'm glad you chimed in, I will do it

I took apart several of the lifters that were flooding & they had spacers under the plunger to lock the cup up against the snap ring to in effect make a solid lifter ostensibly to be able to use shorter pushrods in a prior solid lifter build (not sure how but no wonder they flooded & Dave Hughes said he had never seen/heard of this in his life! (I wont share who backyard engineered that mod!). OK so then I took a set of the lifters that did not flow & got #1 on TDC compression as Dwayne said & preoiled & after what seemed forever it started to lightly flow some oil out onto the (2) rockers (& I'm sure a bit more here & there on some of the others) then I turned it 1/4 turn & preoiled & after the same time wait #8 oiled & so on. Evidently it takes a LONG time for oil to reach the top of the oil thru pushrods. So it ends up with the right lifters in there, the only problem was I did not preoil long enough. Thanks guys (& especially you Dwayne) for your patience here, this one was getting to me. I filled the pushrods with oil & buttoned it all back up & filled the "sled" rocker arms with oil.