The Timing Chain drives the Camshaft.
Also see: * Timing Cover * Crankshaft Pulley
Contents |
Overview
We have seen a couple of single link timing chains on A12, which is the original A10 single row chain. Insist on the factory specified double-chain, like Nissan did for later A10s.
NOT GOOD - early A10 single-row chain
NOTE: A rattle can be the trait of a stretched timing chain. Pinging/pinking has also often been mistaken for timing chain rattle
A-series engine has a short timing chain -- and with an automatic adjuster -- it rarely stretches or goes bad.
Compare to the loooooong chaing used in the Nissan KA24E engine:
click
KA24 often has timing chain problems
Replacement
Alignment
Check the cam gear alignment. It should be exactly like this:
If it is not, see Camshaft#Timing.
Slinger
Don't forget the oil slinger.
Part Numbers
The timing chain kit (timing set) includes: Cam, Crank, Chain, Tensioner
KIT SET * CLOYES Part # 94054S RockAuto.com $35.79 * CLEVITE/PERFECT CIRCLE Part # 92602 * ITM 05390500 RockAuto.com $32
Cam Sprocket
38 tooth Cam Gear (timing gear) * Sealed Power 223478 $3.50 * ITM 50022 $4.67 * ITM 50021 $4.67 * CLOYES Part # S47 RockAuto.com $9.41 * Beck/Arnley 0250282 $10.85
Cam Sprocket Bolt
Special bolt 13082
Chain
Same as SRL311 with U20 engine (for Jackshaft)
CHAIN RockAuto.com * CLOYES Part # S478 $9.40 * CLOYES 94054 $9.70 * BECK/ARNLEY Part # 0240226 * ITM 2354 $7
specs Links: 54 Pitch: 3/8 inch Rollers: Double Timing Marks: 2
Crank Gear Key
Same key is used for the engine crankshaft pulley. See Crank Pulley Parts.
Tensioner
* CLOYES Part # 95005 RockAuto.com $3.90 * ITM 60004 $6.37
Early A12 engines (to April 1970) also used a tensioner on the Tension side of the chain. Apparently this was deemed unnecessary so was omitted starting May 1970.
13083-18001 TENSIONER-CHAIN TENSION SIDE -0470 13084-18000 SUPPORT-TENSIONER TENSION SIDE -0470 08110-62010 BOLT M6 FIXING TENSIONER -0470 full
Crank Sprocket
19 tooth Crankshaft Gear (Timing Crank Sprocket, Timing Crank Gear) RockAuto.com * CLOYES Part # S477 $8.87 * Sealed Power 223477 $6.17 * Beck/Arnley 0250258 $7.36
USA
B110 RAW LIST VALVETRAIN 13024-H8500 SPROCKET-CAMSHAFT 13024-18001 SPROCKET-CAMSHAFT 13082-18000 BOLT-CAMSHAFT SPROCKET 13030-18000 WASHER-CAMSHAFT 08915-2401A WASHER-LOCK 08915-14010 WASHER-LOCK 13028-18001 CHAIN-CAMSHAFT 13070-18001 ASSY-TENSIONER CHAIN 08120-63510 BOLT-FIXING CHAIN TENSIONER 08915-13610 WASHER-LOCK FIXING CHAIN TENSIONER PISTON, CRANKSHAFT & CONNECTING ROD 13021-H1000 SPROCKET-CRANK A12 12316-30000 KEY-WOODRUF 5X16 2 A12
Adjustable Cam Gear
Fitting an adjustable Camshaft gear lets you fine tune the timing. The cam vendor's recommendations are usually best, but retarding the cam a degree or two will generall shift the torque curve higher up in the RPM range. Advancing the cam will (usually) lower the power curve a few RPM.
Adjustable gears come in a few basic kinds:
- Multi-key. Rollmaster had one with nine adjustible keys in the crank sprocket
- Multi-hole. Using different holes
- Variable: Slotted holes allow a continuously variable range