Honda B16A Timing Belt Marks: Crank and Twin-Cam TDC Alignment
Honda B16A timing-belt alignment guide showing crank-to-oil-pump pointer, cam UP marks, horizontal TDC lines, belt tension and hand-rotation checks.
At No. 1 cylinder TDC on a Honda B16A, align the timing mark on the crankshaft timing-belt drive pulley with the pointer on the oil-pump housing. Position both cam pulleys with their UP marks at the top. The horizontal TDC index lines on the intake and exhaust cam pulleys must align with the cylinder-head upper surface and with each other. Keep the crank and cams at those fixed references while installing and tensioning the belt, then rotate the crank counterclockwise by hand and recheck all marks.
B16A timing photographs are easy to misread because the cam gears have several visible features: UP lettering, horizontal edge marks, spokes and sometimes aftermarket degree graduations. Honda's usable TDC reference combines two checks on each stock pulley—UP at the top and the side index lines level with the head surface.
At the bottom, use the small timing-belt drive pulley and cast oil-pump pointer while the lower cover is removed. The outer crank pulley has additional ignition-timing marks used with a timing light; those are not the preferred internal belt-installation reference.
Engine swaps add another risk: a B16A long block may be paired with mounts, covers, crank pulley or ECU/distributor from another B-series application. This page remains indexable but visibly limited until market- and chassis-specific Honda manual illustrations can be attached.
Interactive B16A timing-belt reference
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Pulley-end functional view: both UP marks vertical, both horizontal TDC lines level with the head, and the crank drive-pulley mark at the oil-pump pointer.
Honda B16a Timing Belt Mark Diagram
| APPLICATION / ITEM | SPECIFICATION | NOTES |
|---|---|---|
| Crank reference | Drive-pulley mark to oil-pump pointer | No. 1 TDC |
| Intake cam | UP mark up; TDC line level with head | Do not use UP lettering alone |
| Exhaust cam | UP mark up; TDC line level with head | Lines face/aligned across both gears |
| Rotation direction | Counterclockwise viewed from pulley end | Normal Honda engine direction |
| Final proof | Hand rotation and all fixed marks rechecked | Stop on abnormal resistance |
The B16A is an interference DOHC VTEC engine, so a one-tooth error or uncontrolled cam movement can cause poor running or internal contact. Cam-pulley UP lettering alone is not enough: the horizontal index lines must also sit level with the head surface. Use genuine fixed metal marks rather than paint marks from an unknown previous belt job.
How to use this specification correctly
- 01
Identify the full engine code/suffix and chassis or swap components; obtain the matching Honda service manual and verify belt, tensioner, water-pump and cover part numbers.
- 02
Disconnect the battery, support the engine and remove mounts, accessory belts, crank pulley and timing covers using the chassis-specific procedure and correct crank-holding tool.
- 03
Turn the crankshaft counterclockwise to No. 1 TDC. Align the crank timing-belt drive-pulley mark with the oil-pump pointer.
- 04
Place the intake and exhaust cam pulleys with UP marks at 12 o'clock. Align both horizontal TDC lines exactly with the cylinder-head upper surface.
- 05
Inspect cam/crank pulley teeth, keys, belt, tensioner, water pump and seals. Correct oil or coolant leakage and keep the new belt clean and dry.
- 06
Route the belt in the sequence specified by the Honda manual, keeping tension on the non-tensioner spans so neither cam moves a tooth.
- 07
Apply belt tension with the manual's crank-rotation and tensioner-bolt sequence. Do not pry against the belt or substitute a generic deflection value.
- 08
Recheck the crank pointer, both UP marks and all horizontal cam lines before finalizing covers or using the starter.
- 09
Rotate the crankshaft counterclockwise by hand through at least two complete revolutions. Stop immediately if resistance indicates possible contact.
- 10
Return to No. 1 TDC, recheck every fixed mark and belt tracking, then assemble with the exact fastener procedures and verify idle, vacuum and ignition timing after warm-up.
Cam-pulley UP and horizontal marks
Each stock B16A cam gear has an UP reference that should be visibly at the top at No. 1 TDC. Side index marks form a horizontal line across the two gears and align with the machined cylinder-head surface.
If the UP marks look correct but one horizontal line is above or below the head plane, that cam may be a tooth off. View squarely from the pulley end; camera parallax can make a correct mark appear displaced.
Crank timing-belt pulley versus outer crank pulley
The small toothed drive pulley behind the lower cover has the mechanical TDC mark used against the oil-pump housing pointer. This directly establishes crank position for belt installation.
The outer harmonic pulley carries TDC and ignition-advance lines viewed through the cover pointer. Aftermarket or mixed B-series pulleys can place those lines differently, so do not sacrifice the internal crank reference to make an outer mark appear convenient.
Tensioning without moving the cams
A DOHC belt can pull one cam away from its TDC line as slack is routed. Keep the belt taut across the crank-to-cam and cam-to-cam spans specified by Honda, leaving controlled slack at the tensioner.
Use the Honda tension-setting sequence and normal counterclockwise rotation. Turning backward to correct an overshoot can move slack to the wrong span; continue in the normal direction and approach the reference again.
Swap and aftermarket cam-gear cautions
Adjustable cam gears may have multiple scales, removable hubs or engraved zero marks that do not duplicate stock pulley references. Establish true cam timing from the cam and manufacturer degreeing procedure before assuming both adjustable gears should read zero.
A B18 block/B16 head combination, decked head, aftermarket cam or nonstandard belt can change the intended setup. The stock-mark page can orient the assembly but cannot replace degree-wheel verification for a modified engine.
Final verification checklist
- Exact B16A suffix/chassis or swap parts identified
- Crank drive-pulley mark at oil-pump pointer
- Both cam UP marks at top
- Both cam horizontal marks level with head surface
- Belt clean, correct direction and fully seated
- Water pump/tensioner/seals inspected
- Honda tension-setting sequence completed
- Two counterclockwise hand revolutions completed
- All fixed marks rechecked at No. 1 TDC
- No abnormal tracking, noise or compression symptoms after startup
Honda B16A DOHC VTEC specifications can change by model year, engine, platform, wheel, and installed component. Confirm the VIN or engine identity, part numbers, fastener condition, and the current manufacturer instructions before service.
Honda B16A Timing Belt Marks: Crank and Twin-Cam TDC Alignment FAQs
How should B16A cam gears line up?+
Both UP marks point upward, and the horizontal TDC lines on both gears align with the top surface of the cylinder head.
Where is the B16A crank timing mark for belt installation?+
Use the mark on the crankshaft timing-belt drive pulley aligned with the pointer on the oil-pump housing.
Which direction should a B16A be rotated by hand?+
Counterclockwise when viewed from the crank-pulley end, which is the normal operating direction for this Honda engine.
Is the B16A an interference engine?+
Yes. Incorrect cam timing can allow valve-to-piston contact, so do not use the starter until hand rotation and fixed-mark checks pass.
Can I align only the UP marks?+
No. Also verify the horizontal cam-pulley index lines are level with the cylinder-head surface and the crank is at its oil-pump pointer.
Do adjustable cam gears use the same marks?+
Not necessarily. Follow the gear and camshaft manufacturer's degreeing instructions; engraved zero marks are not automatically equivalent to stock timing.
Technical sources
TorqueSheet favors engine- and component-specific manufacturer instructions over unsourced universal values.
1Honda ServiceExpress repair-publication matrixHonda identifies ServiceExpress as its source for model-specific service manuals, specifications and repair information.↗2Honda B16A maintenance and repair manual archiveThe archived Honda B16A publication supplies the DOHC cam-pulley, crank-pulley and belt-tension procedures for this engine family.↗3Honda 1990 Civic/CRX VTEC service-manual supplementThe model-specific Honda supplement documents B16A VTEC service information and application boundaries for the period Civic/CRX installation.↗