How much lift will the stock lifters handle?

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Baxter61

Baxter61

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Gonna swtich cams in my 5.2 and looking at options. Is there a lift limit to what the stock lifters can handle?

Also secondary question, anyone know approximately how much lift you can put in a stock piston 5.2? I know i'll have to have the heads setup accordingly and theres a lot more plays into it and to mesure, just wondering about "generally speaking" what may work.
 
IDK the answer to your question.
But I can tell you that if you run in the bottom of the lifter, you have a lotta lotta room for the lifters to pump up if the springs cannot keep it together. I think they have a range of .095 or something, and at the valve that is .095x1.5=.143, so if you don't have the room look-out!, you could be buying a new engine; jus saying.

I run an adjustable valve gear and a preload of .020, for exactly that reason.
You could just order shorter pushrods to fit, and then no worries.The trouble with that is yur married to them, but that's probably not an expensive decision.
 
With MOPAROFFICIAL'S contribution of .600, that means say you ran in the middle of the lifter at .050 which at the valve is .075, less some for angularity. Then .600 less .075=.525 valve lift.... for zero clearance. if the lifters pump up the remaining .045 which is .068 less angularity say .008 leaves, .060. So you have to allow an additional .060 in case it happens. Now we are down to a gross lift of .525 less .060 =.465. But what if the valves with the lifters fully pumped up, still have enough inertia to bounce over the nose another .010? now yur down to .455.
Now, I don't think this scenario would ever happen in reality........... but what if it did?
The other scenario with just .020 lifter preload, which being .030 at the valve comes to .600 less .030= .570 allowable valve to piston for zero clearance. Putting proper springs on eliminates or more or less eliminates pump-up, but it's still a good idea to allow some room. Throw in .030 for that, and the max lift becomes ~.540

Lessee .540 or .455 .....................
I'll take proper springs and shorter pushrods for $4000 saved, Mr.Trebec
 
AJ/FormS said:
With MOPAROFFICIAL'S contribution of .600, that means say you ran in the middle of the lifter at .050 which at the valve is .075, less some for angularity. Then .600 less .075=.525 valve lift.... for zero clearance. if the lifters pump up the remaining .045 which is .068 less angularity say .008 leaves, .060. So you have to allow an additional .060 in case it happens. Now we are down to a gross lift of .525 less .060 =.465. But what if the valves with the lifters fully pumped up, still have enough inertia to bounce over the nose another .010? now yur down to .455.
Now, I don't think this scenario would ever happen in reality........... but what if it did?
The other scenario with just .020 lifter preload, which being .030 at the valve comes to .600 less .030= .570 allowable valve to piston for zero clearance. Putting proper springs on eliminates or more or less eliminates pump-up, but it's still a good idea to allow some room. Throw in .030 for that, and the max lift becomes ~.540

Lessee .540 or .455 .....................
I'll take proper springs and shorter pushrods for $4000 saved, Mr.Trebec
Click to expand...
Running fine, lunati .585 lift hyd roller on mp replacement roller lifters, 360 in a '35 plymouth...So I'd say about .600 , cant imagine needing much more. Go solid roller if so.
 
Retainer to guide clearance will limit you somewhere under about .550" lift at the valve if the guides are not getting cut down. The 5.2 and 5.9 Magnums use the same heads. Stock factory lifters can handle any street hydraulic roller that will fit in that head constraint.
I never measured piston to valve clearance on the 5.2 Magnum yet.
 
Im running .550 lift on 2 different motors currently and setting up my turbo motor for .600 lift. All of them are on stock lifters.
 
If it's stock 5.2 bottom end remember pistons are true flat top with no valve relief where as 5.9 has valve relief so what works in a 5.9 may not work in the 5.2
 
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