Should new lifters be primed or "pumped up" before installing? I've always done that but have noticed some say do not pump them up. I searched some old posts and and found varying opinions. I always assumed it would be best to have the lifters pre-loaded so the valves are moving like they should as soon as the engine fires. Thanks
Lifter suppliers do not recommend it, I don't know what lifter manufacturers have to say about it. I've not seen it happen, but apparently it's possible that if the hydraulic lifters are completely full of oil at initial startup, some valves may be left open even when the lifter is on the cam's base circle. The flip side is that the engine will fire just fine with all lifters pumped down. The valves just won't see full lift until they become filled with oil. If there is something unique to the nailheads I'm not aware, so my apologies in advance. Devon
The factory schools that I have been in say to prime them by putting them into a clean container full of clean oil and pump them up and down with a new clean pushrod untill the air bubbles quit coming out of them.....i have done it both ways,,,, if you prime up with the oil pump and rotate the engine by hand as you do, it will go a long way toward priming them up.... with this last nail that I built , it rolled over 3 times and fired up and kept running.... very little lifter noise on start up....
I, and my engine person do not pump them up before the oil system priming operation. With the lifters "dry", it is a lot easier to depress the plunger and get a reading for correct push rod length on each valve set. When all the push rod lengths are calculated, and the correct push rods installed, I/he then primes the oil system, while rotating the engine over by hand, socket and bar on the damper, a few dozen rotations, filling the lifters as the pump is priming the entire oil system while the engine is rotating over. Regards, Milton
The last rebuilding guide to Nailheads that I read said not to pump up the lifters before hand; - not entirely sure of the reasoning though. The first set of lifters I put in this Electra were pumped up; and it ran well enough, and was quiet until about 1000 miles later when it all came apart due to the fact that there were 3 different sizes of lifters in there. This last set I just put it, it clacked for a few seconds, and then primed up, no problems, and the vacuum gauge confirms that.
Prime them at least a little just to demonstrate that they will pump up...better to know now than after assembling the engine to find a defective lifter.
I've always been told to put them in the bucket of clean oil, and let the oil work their way in for a day or so. Considering the differing opinions, maybe this will allow oil in, yet not a full prime, giving you some oil so you don't fire it up with dry lifters(???)
I have been trained to soak them in ATF. I'd like to know why ATF over oil??? I wish I could remember where I've heard that from, but I could understand that if they were used lifters or sticking, to free them up tho...
Maybe I should have clarified my comment; - the book said to soak the lifters in oil, but not to "pump" them up before installation. This goes against what I was trained. But then again I was trained on Small Block Chevys which more or less have to be fully primed. I then coated the lifters with lithium grease, and then installed them. The engine was primed, having just run an hour before. The new lifters clacked for a couple of seconds, and then quieted right down. On a fresh engine, it was suggested just to run the lifters in after leaving them sit in oil, and then prime up the engine before starting. This way the lifters do get primed, and the clearances are properly set with all the parts in place. I guess one of the problems that was encountered was improper torquing of the rocker arm assembly with "solid" or primed lifters. I would agree witht his, because one of my rocker assemblies came apart (snapped the shaft in three places, and broke one of the mounting bolts) after being put together with fully primed lifters. (obviously I goofed the torquing procedure) The rocker assemblies are torqued down to only 25 lbs, and the rocker shaft mounts are made from aluminum, so they are very suseptible to being cracked or broken if improperly torqued down. Because of the funny geometry of the Nailhead rocker system, I can see how easy it would be to screw it up with fully primed lifters, and I'd recommend following what Buick suggests and leave the lifters un-primed.
ATF has a lot of detergent compared with plain engine oil. It would most likely be for used lifters to make sure any dirt/gunk is cleaned off before going back into an engine.
Really the only way to do that properly is to disassemble and clean each lifter, making sure the parts go back into their corresponding lifter bodies. Devon
Whether they need "pumped up" or "primed up" is the original question I'm not sure has been answered with a clear consensus. Sounds like Jason's original question has led to a fairly even split in opinions. It would seem to me it would be more practical to soak them in EOS or coat them in cam break-in lube for the ZDDP properties rather than a detergent on a NEW break-in assembly. That would make more sense to me... If they are used, stuck, and/or need cleaned; that is a horse of a different color. I would then agree with the disassembly and any good cleaner should do. Erik
Erik, we're on the same page regarding cleaning, but I see no need to soak lifters in a zinc-rich oil solution as there are no surfaces inside the hydraulic lifter that need such high pressure help. The only surface that needs that kind of help is the interface between the cam lobe and the base of the lifter itself. Any light weight oil at that interface will be wiped quickly after initial startup, which is why it's good to use the thick moly-based paste there. The high zinc additive needs to be in the sump, well mixed with the oil for startup. If the new lifters aren't dirty, haven't been sitting upside down or on their sides over a long period of time, a splash of motor oil should be just fine. Devon
i agree with Dev, I use moly grease on cams and the foots of the lifters and on the ends of the pushrods and the tips of the rocker arms.... That stuff will last for weeks and months and not run off of the part s.....
