Quick question about reinstalling hydraulic lifters in 4.1 liter six. Getting conflicting info from coworkers. While reinstalling head on 74 comet with 250 six cyl. after valve job, should lifters be hard and full of oil ? or Bled down. seems to me they should be bled to avoid bending push rods or valve stems. Thanks.
preferably full of oil, though that usually doesn't happen as the only practical way to get oil inside is pressure from oiling system(for filling soaking is mostly a joke)... This said as long as plunger is extended you can adj them approx 1/2-3/4 turn and that's all that's necessary... Which leads to question, are 250 lifters adjustable??? I thought they were non adjustable...
Hydraulic lifters are supposed to be installed dry (with the faces lubricated with cam lube). It is a myth that they're supposed to be full of oil and "pumped up". They have an internal spring, so the plunger will always be fully extended with no pre-load. After adjusting pre-load, prime the oil pump with a drill and primer tool. Verify that oil is flowing over the tops of the rocker arms. If it is, the lifters are pumping up as they should.
(afaik) No 4.1 L6 engines came stock - OEM with adjustable lifters. Replacement and mixed rocker parts with non-adjustable parts can be a crap shoot. Reconditioned adjustable and higher-ratio small block six stock and performance valve train parts available at: http://www.rockerarms.com/ For adjustable small block six rockers , just take the plugs out so you can easily spin the engine with a socket on the crank-balancer. Take off VC and watch when each cylinder to be sure the lifter is OFF the cam lobe. Usually just watch the cylinders' other valve is ON the cam lobe to be sure. Then tighten lifter until you can just turn with your fingers. If engine has not been started, pre-lubing with drill on oil pump shaft is recommended. have fun . .
'60-'62 small six's have solid lifters. Ford went to hydraulic lifters in '63. Ford used up the adjustable rocker arms bin on hydraulic cams then went to the "new" non-adjustable rockers. By the time the 250 came along in '69 the adjustable rockers were in the history books. Only way to adjust hydraulic lifter is to use a longer or shorter pushrods.
... leads me to believe there were some parts tolerance differences needed to compensate in factory assembly that may show up when swapped. A good running Maverick 250 with @40 k original miles had a seriously bent pushrod when I disassembled... . have fun
you don't have to put in the extra effort to pump lifters up prior to assembly.. but it's still highly recommended to presoak them by all the engine builders that I've ever talked to. The longer they sit the better and overnight is obviously going to be better then 1 hour by far. Makes perfect sense when you think about the additional air volume and time needed to purge them and start oiling the pushrods, rockers, and springs. The only time that it's not considered best practice is when you're going to be pre-priming the engine prior to startup. Then it would just be wasted time anyways as the lifters will be fully purged of air at startup. If you've ever pre-primed an oiling system on an engine it's pretty obvious as to how much air needs to be displaced until the oil starts flowing through all the pushrods. The way the oiling circuits run on most motors the last lifters in the line can take almost 1 full minute or more of priming and you don't want that kind of wear and tear issues on any motor. Especially a new cam and lifter install. It's also highly advisable to mate each lifter to the same exact cam lobe that it was removed from if they have already been run in due to core shift and machining variations between lifter bores and the cam itself. Otherwise you can wipe a lobe even with weaker springs like these.
on a used hyd. lifter, if you don't collapse it the lifter will be full of oil... I've never "broke" a cam in...never wiped a cam. had friends and heard of others that have followed break in instructions and still wiped one... depending on the miles on his motor, I would be more worried about the bottom end staying together...
...and if you crank a small block six with the VC off it's disconcerting to see how long it actually takes to get oil up to front rockers... have fun
"you" don't need to collapse a lifter for some of the oil to be expelled. The valve springs will often do that for you on any valves that remain open while the car is parked for longer periods before lifter removal. But I do agree that if the setup is previously used it shouldn't be a major concern and was more or less replying to Larry's comment of the "myth of not needing to worry about lifters being dry". As I mentioned above, the biggest concern with used lifters is to properly remate them to the lobes that they have previously worn against. Not all lifters will wear the same due to the machining tolerances, cam lobe/bore alignment variations(some blocks and cams are terrible in this respect) and lifter rotations being different between many of them. This wipes out the lifters original crown(which is designed into the lifters face for proper rotation) and even causes some that rotate less than others to become slightly dished to mate with specific lobes that have worn in similar fashion as a result. These springs are very weak so that's definitely a good thing when it comes to swapping lifters around between lobes(would be similar to using lighter break-in springs and/or reduced ratio rockers on the performance type setups). I've also seen people wipe cams when mismatching previously worn lifters being paired with higher spring pressures. And I too have also seen some still wipe cams despite following all the cookie cutter recommendations. But best practice is still best practice regardless of some occasionally getting away with less than desirable building practices.. or those who don't pay attention to the little details that can come back to bite them and blame the parts quality themselves. Bigger problem is that people far too often trust mechanical parts, engine block included, to be properly machined and sufficiently clearanced for the task at hand. That is not the case every time and is specifically why all the best engine builders will check and measure every single component being used prior to assembly. And I myself would be far more concerned about the crappy valve guides and horrible valve stem seals on these motors than anything else.
If the rocker arm shaft wasn't installed slow and even to allow the oil to bleed out of the lifter then it will bend the pushrod or bend the rocker arm shaft. No need to soak the lifters...just use assembly lube on the foot of the lifter and drop them in the lifter bore. Use assembly lube on pushrod ends too.
