Now you can no longer claim that. I will tell you it's happened to me. A filled hydraulic lifter is not easily compressible, you have to let it bleed down as you tight down on it. You reef down too quick on the rocker and the lifter will not bleed down fast enough and you will bend the pushrod, BTDT, and it'll pop out on you when you are leaving the doctor's office with a sick kick and zero oil pressure because the lifter is now setting in the valley and all the oil is dumping back into the crankcase. That is why Comp tells you not to do that. But hey, what does Comp's experience and engineering mean against an opinion anyway.

Comp's engineering and experience has gotten him through 2 sets of lifters with the same problem. Comp sucks. Like I said people have been pumping up their hydro lifters forever.

I understand what you're saying, and I understand why that could happen in theory. But he wants to fix his noisy lifters, and you are the only person I've ever heard of this happening to, I would guess because a retainer bolt nearest to the pushrod that bent was driven in too far before the others were driven in, side loading the pushrod and causing it to flex, and this was the real cause of the issue. Maybe, maybe not, but with the lifter pumped up to the max really all that should happen is the valve will open as the rocker shaft is tightened down. What you're saying could happen any time a rocker shaft assembly is installed/reinstalled, or even with the lifters not pumped up. You know whats harder to compress than a pumped up lifter? One that the cup is bottomed out in (or a solid lifter). Although the extra clearance of not being pumped up might help.

IMO the only thing a set of freshly pumped up lifters would do is screw with cam timing until they bleed down. I would think that is the reason Comp says not to pump them up, in case you get a valve trying to hang open on initial start up until the lifter bleeds down. I agree that priming the oiling system should also fix the issue, but hydraulic systems with air in them can be difficult to bleed. I'm done debating it and the OP can do as he wishes with the information provided.

OP let us know how it turns out.

thanks for advice but honestly I lost trust in these lifters, I'm not sure they can hold pressure anyway.
About Valve spring I regret I followed the recommended components for cam HE275Xl, I had the single 911 and took out to install the double 924 with the extra job of machining heads guide bosses etc etc..

I also would like to go pro magnums, I have nothing against Comp's and I'd buy again from them. the only problem is the ocean between when it's time to buy parts.

the history of this motor is a long history and I really don't want to bother with too much telling. Important to say that I'm not addressing responsability to any builder , since I have performed myself all the works on this engine, and of course I have maximun respect of Comp's as they sell thousands of parts and I assume they know their job very well.
All I can say is that before istalling the HE275XL with spring 924, I had another Comp's cam of thump series (the 279) with valve spring 911 and I didnt experienced any problem with lifters bleeding.
Honestly I wanted a bit more power so I decided for the cam swap , since I had the 275XL unopened package at home from many years.
Now I'm taking some days to read and try to figure out what to do, thanks for help

the 924 springs are not a heavy spring. they are just a little more high lift friendly.

With that bit of information I would suggest contacting comp cams and see what they say. based on the information I would say you may have gotten a bad set of lifters.

When you shut the engine off, oil pressure goes away and the lifters bleed back down. That part is normal. Hand rotating the crankshaft is not fast enough to build enough oil pressure to pump the lifters back up. Once you start the engine, lifters should be fully pumped back up in a few seconds. When the engine is shut off, hydraulic lifters do not stay pump up like solid ones.

To my understanding some of the higher performance lifters are made with a little more internal clearance to prevent lifter pump up as RPM goes up. Cheaper ones do seem to run a lot quieter for me. Also a lot of people complain about the XEHL cams making noise. Probably be worth changing oil weight before panicking.

Yes, that's correct, what I see not-normal is that lifters bleed down so much with engine off, and the engine would start very noisy and would not be silent until very warm. It's true the oil 20W-50 is thick but I 've always used this gradation since ,before on a 383 and then with 440 without hearing any valvetrain ticking even after months of parking.

I dont want to insist on this thread too much, I received a lot of hints and I appreciate it, really.

So the decision I'm going to take is to order a new set of lifters of higher quality or let's say more engineered for hi lift cams.

From Summit catalog online I'd buy a set among these ones:

COMP Cams Pro Magnum Hydraulic Lifters 867-16 $97.97
Crower Camsaver Hydraulic Lifters 66031X3-16- $109.97
Crane Anti-Pump Up Hydraulic Lifters 99278-16-$101.60

I know there are other engine parts involved in this issue so i do not pretend that anyone without seeing the motor can give the right solution but..thank you in advance for any advise about which set would be more desiderable in theory for a cam XE275HL with 924-16 valve springs.

Try a lighter oil first. That is a simple test which doesn't cost much money. Put a 5W-30 in there and see if the lifters pump up quicker on cold start.

If your spring rate is the same and you have more lift now than the valves that stop fully open will have more pressure bleeding it down than the old cam.

Hi everybody,
after a month this topic is still the main problem for this 440 motor.
During this time I performed new tests,I tried old stock valvetrain with no results.Than I put back adjustable with more and less preload,nothing. Than I put lighter engine oil ( 10W-40) but the problem is still the same:
Only on passenger side, lifter / lifters under valve opened BLEED OFF overnight and take 3-5 minutes to pump up until the lash is gone and ticking go away.

yesterday I was in bad moon and took apart the heads because the very different valve spring installed height between cylinders make me nervous, moreover I want to check more measurements and even each cc combustion chamber because I'm sure I have something wrong on heads.

Thank you for support

Might be as mentioned that the new set of lifters (would only take one or two bad ones to make a racket) are bad. If your preload is good and your psi is good and your oil weight is good, not much left. I did have noisy ones on a later /6 with hyd lifters. it would come and go (mostly at idle) but usually when started & I just lived with it. EDIT & when it would come and go randomly the psi was OK. If I ran into that I'd take apart each lifter/clean/reassemble the pieces (same innards in same body & as you know same lifter back in same hole) & if that did not do it then I'd spring for a nother set & do the cam breakin procedure

yes .. for the 2nd time I'll have again this set carefully cleaned and reassembled to be sure they go inside the holes better than new out box.
Anyway tomorrow I'll take heads to machine shop to see what we can do to get the installed spring height as close as possible to 1.900 recomm value.
actually these vintage DC stage IV heads, ported and cut more time in their life have some valves quite recessed expecially intake ( dont know why) and even worse the stems were cutted to balance .. ( these jobs belong to the past of this car) so will update how it ends more ahead. thanks

After plus one year trying to fix a multitude of problems in my free time on weekends, yesterday afternoon for the first time I felt like to quit and sell the car. Before that, I’m asking again to someone for help, in no way I will take the car again to any mechanic in my town or in the whole Italy too!


the UNSOLVED problem is actually the sound of ticking on valve train,expecially when engine hot. If I pull the valve cover I see some free play pressing on rockers , like some lifters are spongy.
I tried also magnum –race lifters but these were a nightmare with the recommended almost zero preload .. I tried to increase preload to standard lifter but nothing solved ..
Oil pressure is ok , first I put Valvoline 20W50 and some lifters needed a lot of time to fill with engine cold ..so I put the Royal Purple 5W30, maybe too thin , but they pump suddenly after started engine. I wonder what is killing the ability of hydraulic lifters to do their work of maintaining zero lash in this engine.

I also tried to pull out all lifters , disassemble and clean them like were my teeth, but the problem when engine gets hot is always the same.

Really Thank you in advance.
Roberto

someone may have restricted the oil flow to the lifters, pull the front lifters out on pass side & get a oil pump priming tool & spin the oil pump, you will be able to see if you have good oil flow to the lifters.

Aftermarket adjustable rockers? Got the preload set right?
Pushrod length good?