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Revision as of 11:17, 14 August 2016

The Timing Chain drives the Camshaft.

Also see: 
* Timing Cover
* Crankshaft Pulley

1 Overview
2 Checking For Wear
3 Replacement
- 3.1 Alignment
- 3.2 Slinger
4 Part Numbers
5 Adjustable Cam Gear
6 Gear Drive

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

super-strong Double-Roller chain is standard
album

Checking For Wear

If tensioner spindle projection is more than 15mm, replace chain. Rotate the engine clockwise a bit, then check the distance.

Album 24796

This ones looks to be at the limit:

Replacement

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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.

12302-18000 THROWER-OIL CRANKSHAFT

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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

full

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 non-return tensioner (A10 engine)
* 13070-18010 ASS'Y-TENSIONER, non-return B10 [double-chain]

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.