2000 Jeep 4.0 Max Valve Lift

[trombly]

What is the max valve lift I can go on a stock 4.0 bottom end without hitting the pistons?
Thanks guys! (forum is awesome btw too)

[Retlaw01XJ]

The 4.0/4.6 has ample valve-piston clearance. Shouldn't be an issue unless you get real crazy with mods.
Valve spring/retainer/valve height IS a concern with higher lifts.
A stock setup should work up to 0.460" valve lift. More lift will require some mods to the valvetrain or head machining.
Some stock measurements here:
http://www.jeepstrokers.com/forum/viewt ... =coil+bind

[trombly]

So if I change the springs to .550 with a .460/.476 lift cam I should be alright?

[Retlaw01XJ]

So if I change the springs to .550 with a .460/.476 lift cam I should be alright?

0.476" lift should theoretically work with stock springs, but you would be exceeding the safety margin... it would not be recommended. Spring pressure may be too low as well.
I don't know what you mean by .550 springs?
Replacement performance springs usually require new retainers and locks. Might need a bit of head machineing too.