N54 crankhub and timing guide
Factory torque specs, special tools, and honest job sequences for the N54 crankhub, vibration damper, timing chain, and VANOS adjusters — from ISTA.
The N54 is the engine that made the crankhub a household word in the BMW world. On this engine the vibration damper is a ring bolted to a hub, and the hub is clamped to the crank nose by one central bolt — the drive to the oil pump and timing chain sprocket runs through friction plates between those faces. ISTA is blunt about what that means: the friction stack is a wear-and-installation-critical item, and the central bolt is a replace-every-time fastener. Here is every number the factory data carries for that job, and for the chain and VANOS work behind it.
The crankhub, factory view
The N54 damper R&R itself (11 23 010) is screws-out, damper-off — the hub underneath is untouched. The real crankhub work lives in the timing chain job (11 31 051), where the central bolt comes out and the hub comes off the crank nose. Two factory laws govern it:
- The N54 requires special friction plates between the friction surfaces. ISTA's words: the engine will incur damage if the friction plates are damaged or not fitted. They clip onto the sprocket/oil-pump module — check them every time the hub is off.
- The central bolt is torque-plus-angle and single-use. Lightly oil the screw and thread, then torque it in stages.
Crankhub torque table
| Fastener | Thread | Spec | Torque |
|---|---|---|---|
| Hub (torsion damper) to crankshaft, central bolt 12.9 | M16x80 | Replace. Lightly oil screw and thread | 100 Nm (73.8 lb-ft) + 360° |
| Vibration damper to crankshaft hub, ASA screws | M8 x 16 | — | 35 Nm (25.8 lb-ft) |
Special tools
- `11 0 300` — locks the crankshaft at TDC (slides into the block; see the TDC-bore gotcha below)
- `11 4 280` — counterhold for the flywheel/engine locking during the chain job
- `11 9 260` — block crankshaft (engine or gearbox removed)
- `11 8 660` — block crankshaft on the gearbox (automatic)
- `11 8 180` — flywheel holding fixture (manual gearbox)
- `00 9 140` — secures the new central bolt during installation (magnet-mounted to the engine support)
- `11 4 281` / `11 4 283` — camshaft locking fixtures for timing check/adjust
- `11 8 520` — increment-wheel alignment fixture
- `11 9 340` + `00 9 250` — chain tensioner pre-tension tool and torque wrench (0.6 Nm)
- `00 9 120` — central-bolt socket for the camshaft adjuster bolts
Crankhub job sequence (honest summary)
The full procedure is 11 31 051; this is the shape of it, not a substitute:
- Preliminaries: fan cowl, cylinder head cover, spark plugs, chain tensioner, front crank seal, belt tensioner, vibration damper, intake and exhaust adjusters come off.
- Rotate to firing TDC of cylinder 1 and lock the crank with `11 0 300`. Mark flywheel to transmission housing.
- Hold the crank (tool depends on transmission: `11 9 260` / `11 8 660` + `11 8 180`), remove `11 0 300`, and crack the central bolt with 3/4-inch drive. Hub comes off the front.
- Free the chain drive module (top screw, bottom screw, side screws), lift the module with chain and sprocket.
- Inspect and refit the friction plates — they clip onto the sprocket/oil-pump module, one pushes on without retainers.
- Reassemble in reverse: chain held under tension, sprocket collar facing the crankshaft, new central bolt at 100 Nm + 360°, secured with `00 9 140` during the fight.
- Crank it twice by hand and re-check the timing before anything else goes back on.
Timing chain, guides, and tensioner
Chain replacement is the same job as the crankhub — the chain module comes out as part of it. The rail and tensioner numbers:
| Fastener | Thread | Torque |
|---|---|---|
| Chain drive module to cylinder head | M6 x 35 | 8.5 Nm (6.3 lb-ft) |
| Guide rail to crankcase | M8 | 20 Nm (14.8 lb-ft) |
| Guide rail to cylinder head | M7 | 14 Nm (10.3 lb-ft) |
| Chain tensioner to cylinder head | M22 x 1.5 | 55 Nm (40.6 lb-ft) |
| Screw plug in cylinder head | M18 x 1.5 | 25 Nm (18.4 lb-ft) |
| Camshaft bearing strips (steel screw 10.9) | M7 x 70 | 8 Nm (5.9 lb-ft) + 60°, inserted dry |
The tensioner on its own (11 31 090) is an accessible job — coolant expansion tank out on an E89, then the tensioner unbolts with a cloth ready to catch the oil that follows. Keep that oil off the belt drive.
VANOS adjuster bolts
| Fastener | Thread | Spec | Torque |
|---|---|---|---|
| VANOS unit with sensor gear to inlet and exhaust camshafts | M10 x 94 | Replace screw | 20 Nm (14.8 lb-ft) + 180° |
| Non-return valve VANOS to cylinder head | M14 x 1.5 | — | 13 Nm (9.6 lb-ft) |
Opening those central bolts: grip the hexagon on the rear of the camshaft, release only with counterhold 11 4 280. Intake and exhaust adjusters are marked (EIN/IN vs AUS/EX) and are not interchangeable — mixing them up is engine damage, straight from the doc.
Checking and setting the timing
- Adjusters must be at their locked base position before you judge timing — check the lock and rotate the camshafts to lock them if needed.
- `11 0 300` in the correct bore, cylinder 1 at firing TDC, cams of both shafts at cylinder 6 pointing down at an angle, follower unactuated.
- `11 4 283` bolts to the head; `11 4 281` mounts across the camshafts. If `11 4 281` will not seat, the timing needs adjusting.
- Adjusting: release both adjuster central bolts (replace), align the increment wheels with `11 8 520`, pull the tensioner, screw `11 9 340` in its place, pre-tension the chain to **0.6 Nm (0.4 lb-ft)** with `00 9 250`, then torque the adjuster bolts with `00 9 120`.
- Crank twice in the direction of rotation and re-check.
Coverage notes
What the ISTA data does and does not carry: complete procedures, torques, and tooling for the damper, hub, chain, tensioner, and VANOS work — all of it above, traced to document ids. It does not carry failure-mileage statistics or a wear limit for the hub's friction surfaces; any "these fail at X miles" claim you read on a forum is folklore, not factory data. Treat the friction-plate inspection as the factory's answer to the question.
Every number on this page traces to the ISTA document ids listed in the sources. The complete step-by-step procedures live in ISTA itself — this page is the cheat sheet you keep next to it.
- 11 23 010 — Removing and installing/replacing vibration damper (N54, N54T)
- 11 31 051 — Replacing timing chain (N54, N54T)
- 11 31 090 — Installing and removing/replacing chain tensioner piston (N54, N54T)
- 11 31 005 — Checking camshaft timing (N54, N54T)
- 11 31 505 — Adjusting camshaft timing (N54, N54T)
- 11 36 046 — Removing and installing/replacing intake and exhaust camshaft adjusters (N54, N54T)
- 11 21 1AZ — Torsion damper (hub) to crankshaft, central bolt (N54, N54T)
- 11 23 1AZ — Vibration damper to crankshaft hub screws (N54, N54T)
- 11 31 2–6AZ — Chain drive module, guide rails, chain tensioner (N54, N54T)
- 11 36 1AZ — VANOS with sensor gear to inlet and exhaust camshafts (N54, N54T)