Rocker arm fasteners are light — 15 to 25 ft·lbs for most shaft and pedestal designs. Values by engine family, plus how to set lash on adjustable rockers where torque is not the answer.
Short answer: most rocker arm fasteners take 15–25 ft·lbs (20–34 N·m) — GM LS is 22 ft·lbs, Honda K-series shaft bolts 16 ft·lbs, Chrysler Hemi shaft bolts 21 ft·lbs. Adjustable stud-mounted rockers are different: the nut is set by valve lash procedure, not by a torque figure.
| Engine family | Design | ft·lbs | N·m |
|---|---|---|---|
| GM LS / LT V8 | Pedestal, bolt-down | 22 | 30 |
| Chevrolet small-block, self-aligning | Pedestal, bolt-down | 20 | 27 |
| Chrysler Hemi | Shaft-mounted | 21 | 28 |
| Honda / Acura K-series | Shaft-mounted | 16 | 22 |
| Toyota 4-cylinder | Shaft-mounted | 14–16 | 19–22 |
| Ford modular 4.6 / 5.4 | Pedestal, bolt-down | 20–25 | 27–34 |
| Subaru EJ | Shaft-mounted | 13–16 | 18–22 |
| Chevrolet small-block, adjustable | Stud-mounted nut | Set by lash | — |
Shaft-mounted rockers. The whole assembly bolts to the head on a common shaft. Tighten the shaft bolts progressively from the centre outward in two or three passes so the shaft is not bowed — pulling one end down fully first bends it and binds the rockers.
Pedestal or bolt-down rockers. Each rocker has its own bolt into a machined pedestal that sets the geometry. There is no adjustment: torque to spec with the lifter on the base circle of the cam and the geometry is correct by design.
Adjustable stud-mounted rockers. There is no meaningful torque figure for the adjusting nut — its position sets the valve lash. Rotate the engine so the lifter is on the base circle, take up all free play until the pushrod just loses its side-to-side spin, then apply the specified preload (commonly half to three quarters of a turn for hydraulic lifters) or set the feeler-gauge clearance for solid lifters. Lock the nut afterwards if the design has a locking screw.
Base circle, every time. Every rocker must be tightened with its cam lobe pointing away from the lifter. Torquing a rocker while the lobe is lifting bends pushrods and can bottom a hydraulic lifter.
Work in firing order or by cylinder pairs. Rotating the crank to bring each cylinder to top dead centre on the compression stroke puts both of its rockers on the base circle at once. Doing all of them in that order avoids missing one.
Prime and soak new hydraulic lifters. A dry lifter compresses differently and gives a false preload reading. Soak them in clean engine oil before assembly.
Check pushrod length after any head or block machining. Decking a block or milling a head changes rocker geometry. The correct fix is a pushrod length check, not extra preload on the adjuster.
The cover that goes back over the rockers
Staged sequences and TTY bolts
For valvetrain specs given in inch-pounds
Reference for a standard 8 mm fastener
Most rocker arm bolts take 15–25 ft·lbs (20–34 N·m). GM LS pedestal bolts are 22 ft·lbs, Chrysler Hemi shaft bolts 21 ft·lbs, Honda K-series shaft bolts 16 ft·lbs and Toyota 4-cylinder shaft bolts 14–16 ft·lbs.
Not by torque. With the lifter on the cam's base circle, take up the free play until the pushrod just stops spinning freely, then apply the specified preload — commonly half to three quarters of a turn on a hydraulic lifter — or set the specified clearance with a feeler gauge on a solid lifter.
From the centre outward, in two or three progressive passes. Pulling one end of the shaft down to full torque first bows it, which binds the rockers on the shaft.
It is the round part of the cam lobe, opposite the lift ramp. A rocker must be tightened or adjusted only when its lobe is on the base circle — otherwise the cam is already pushing the valve open and any preload you set is wrong.
On aluminium heads the threads strip or the bolt snaps. On pedestal designs, over-torquing can also crack the pedestal, which changes rocker geometry and causes rapid valve tip and guide wear.