Honda N600 Engine Timing Chain Tensioner Schematic and Installation Guide
Replace the automatic adjuster with a manual ratcheting unit if frequent tension loss occurs. Factory-issue spring-loaded plungers lose tension after 12 000 km; a screw-type replacement maintains 12–14 Nm torque without slack. Locate the drive cover at the crankshaft pulley side–remove four 8 mm bolts and the 17 mm crankshaft bolt with a torque wrench set to 54 Nm.
Align the sprocket marks before loosening the camshaft gear. Rotate the crankshaft clockwise until the dowel pin aligns with the V-groove on the crankshaft sprocket; the camshaft sprocket should display a circular punch mark facing upward. Use a 10 mm socket to release the camshaft gear–apply penetrating oil if seized; torque specification is 18 Nm.
Inspect the guide rail for wear beyond 0.8 mm. Measure groove depth using digital calipers at three points: near the camshaft sprocket, midpoint, and crankshaft sprocket. Replace rails if variance exceeds 0.1 mm–aftermarket rails require clearance checks of 0.3–0.4 mm against the block surface. Secure rails with Loctite 242 before final assembly.
Reassemble with new gaskets–apply anaerobic sealant at the camshaft cover and oil pan mating surfaces. Tighten the cover bolts in a spiral sequence: begin at the center, alternating sides, final torque 8 Nm. Rotate the crankshaft two full turns by hand; verify sprocket alignment and tensioner travel–noise should cease within four seconds of startup.
Understanding the S600 Engine Camshaft Drive Mechanism Guide
Inspect the automatic adjuster before attempting repairs–its plastic guide rail often fails first. Locate the spring-loaded plunger inside the aluminum housing (part #14501-410-010) and check for cracks or deformation. Replace if the rail thickness measures below 3.5mm at any point, using only OEM-spec DuPont Delrin for aftermarket fabrication.
- Remove oil pan to access the lower mounting bolt (10mm, torque: 18 Nm)
- Rotate crankshaft clockwise until timing marks align at TDC (compression stroke)
- Disconnect the adjuster’s oil feed line (6mm banjo bolt) to prevent hydraulic lock during disassembly
- Note the plunger’s position–it should protrude 12-14mm when properly tensioned
Verify the secondary sprocket’s thrust washer (0.3mm thick) hasn’t worn through–measure clearance with a feeler gauge (max 0.15mm). During reassembly, apply molybdenum disulfide grease to the rail’s contact surface, avoiding the sprocket teeth. If the manual locknut (17mm) shows rounding, replace the entire assembly rather than reusing–thread failure causes sudden slack with catastrophic valve collision risk.
Finding the Cam Drive Adjuster on the S600 Powerplant
Begin by removing the valve cover–secured with six bolts along the perimeter. The adjuster sits directly beneath the camshaft sprocket, concealed behind a thin metal plate fastened by two 10mm bolts. Use a magnetic retrieval tool to prevent losing the fasteners when lifting the plate.
The adjuster mechanism consists of a spring-loaded plunger housed in an aluminum cylinder. Locate it on the right side of the block, adjacent to the coolant passage. A small dowel pin maintains alignment; ensure it remains undamaged during disassembly.
Accessing Without Full Disassembly
For quick inspections, a bore scope can be inserted through the oil filler neck. Tilt the scope downward at a 25-degree angle to view the adjuster’s base. If debris or slippage is visible, remove the sump pan for complete access–avoid prying near the crankshaft seal.
The factory manual references a “jet valve” near the adjuster, but this is a misnomer. The component is a lubrication nozzle delivering oil to the cam lobes, critical for preventing premature wear. Clear the nozzle’s orifice with 0.5mm wire if clogged.
Common Misidentifications
Enthusiasts often mistake the distributor drive gear for the adjuster. The gear sits left of center on the block, driven by helical teeth, while the adjuster remains stationary unless manually reset. Never force rotation–apply firm pressure to the ratcheting arm only when the engine is at TDC.
Reinstallation requires torquing the cover plate to 8-9 ft-lbs. Over-tightening distorts the gasket, leading to oil seepage. Confirm proper engagement by listening for a faint click when the plunger extends post-startup–absence indicates misalignment or spring fatigue.
Step-by-Step Guide to Disassembling the Camshaft Drive Adjuster Unit
First, drain the cooling system and remove the upper radiator hose to access the front engine cover. Mark the position of the camshaft sprocket relative to the crankshaft pulley using a scribe or paint–this ensures proper synchronization during reassembly. Disconnect the spark plug wires and secure them away from the work area to avoid interference.
Locate the adjuster assembly bolt–typically a 14mm fastener–near the base of the valve gear housing. Use a socket wrench with an extension to break the bolt loose, then carefully withdraw it by hand. The adjuster piston may be under spring pressure, so apply controlled force to prevent sudden ejection. If stuck, tap gently with a soft-faced mallet around the housing while rotating the bolt counterclockwise.
With the bolt removed, slide out the piston and spring. Inspect the bore for debris or scoring; clean with compressed air or a lint-free cloth if necessary. Note the orientation of the spring and piston–some models have a directional oil passage that must align during reinstallation. Check the gasket surface on both the housing and engine block for warping or old sealant residue, scraping carefully with a plastic scraper if needed.
Before reassembly, apply a thin layer of assembly lubricant to the piston and bore. Replace the O-ring or gasket if hardened or cracked. Insert the spring first, followed by the piston, ensuring it seats fully. Torque the adjuster bolt to 22-25 Nm, then rotate the crankshaft two full turns by hand–listen for smooth operation without binding or unusual noise.
Key Components of the Air-Cooled 600cc Valvetrain Guide System
Inspect the hydraulic adjuster assembly first–its plunger and spring must move freely without binding. A stuck plunger causes erratic valve clearance, leading to compression loss or piston-valve interference. Measure the spring’s preload at 12.5–14.5 N before installation; values outside this range indicate fatigue. Replace the adjuster if the internal oil passage shows signs of sludge, as even minor blockages disrupt pressure regulation.
| Component | Material | Failure Signs | Critical Dimension |
|---|---|---|---|
| Guide Rail | Nylon-6/6 or Aluminum Alloy | Chipping, groove wear >0.3mm | Length: 147±0.2mm |
| Locking Pawl | Case-Hardened Steel | Tooth rounding, cracks | Engagement depth: 1.8–2.2mm |
| Pressure Relief Valve | Brass | Oil seepage, valve seat corrosion | Orifice diameter: 1.2±0.05mm |
Ensure the guide shoe’s wear pad remains parallel to the drive link; misalignment >0.15mm accelerates sprocket tooth erosion. Lubricate the pivot pin with 75W-90 gear oil before assembly–generic motor oil lacks the shear stability needed for sustained 90°C+ operation. Verify the ratcheting mechanism’s pawl engagement by applying 35 Nm torque to the crankshaft pulley; a functioning system will emit a sharp, single click per tooth advance.
Decoding the Adjustment Blueprint for Valve Train Component Regulation
Locate the spring-loaded plunger on the reference guide–its position relative to the camshaft sprocket indicates preload settings. Factory specs require 3.5–4.2 mm of exposed plunger shaft before engagement; deviations outside this range risk premature wear or slack-induced misalignment. Use calipers to measure precisely, accounting for thermal expansion if the assembly is recently run.
Trace the hydraulic actuating line depicted in dashed notation; this pathway connects the oil gallery to the tensioning device. Confirm no air pockets exist by priming the system with fluid before final adjustment–air bubbles distort pressure readings. The feed orifice diameter should match the 0.8 mm marking; anything larger invites pressure drop, while a smaller bore restricts necessary flow.
Critical Mark Alignment Verification
Observe the crankshaft pulley index relative to the front cover’s etched markers–misalignment by even 2° alters valve operation timing. Rotate the assembly manually to Top Dead Center for cylinder one, then recheck that the linkage arm rests flush against the slipper pad. Any gap exceeding 0.1 mm signals improper tension, requiring spring compression adjustment via the threaded rod.
Examine the one-way ratcheting mechanism depicted in exploded view–its teeth must engage smoothly without binding. Lubricate contact points with molybdenum disulfide paste to prevent false lock-up; graphite substitutes fail under heat cycling. If the pawl skips under load, replace the entire subassembly rather than attempting realignment.
Document all measurements against the sectioned illustration’s callouts using a non-permanent marker on the housing. Cross-reference with a torque chart: the pivot bolt requires 22–26 N·m, while the adjuster locknut tolerates 12–15 N·m only. Over-tightening distorts the casting, causing irregular torque transfer patterns detectable during engine warm-up tests.