DIY Network

Timing Chain Replacement -- Timing-Chain Kit From "Weekend Mechanic" episode WKM-112

advertisement

Figure A Figure B The worn-out timing chain will be replaced with this new, performance chain. Figure D Figure E Figure F Figure G Figure H Figure I Figure J Figure K Figure L Figure M Figure N Figure O

Timing Chain Kit

With all of the necessary parts removed, including the old chain and crankshaft and camshaft sprockets, the new timing chain and associated gears can be installed.

Important: Included below are the steps in this automotive procedure as shown in the episode. These steps are general guidelines that are applicable to most vehicles. With any particular vehicle, there may be procedures, specifications, settings, tolerances, components, etc. that are specific to that vehicle. There are also variations according to the type and brand of repair-kit you select. Always consult your vehicle's service manual when undertaking significant automotive repairs, and read and follow the manufacturer's directions and precautions that come with your kit or replacement parts.

Safety Alert: Always wear eye protection, and follow proper safety precautions, when working with power tools.

Safety Alert: As a standard safety precaution, always disconnect the vehicle's negative battery cable before you begin work on any electrical or mechanical components.

The standard timing-chain components (figure A), like those that were in the Camaro, are being replaced with a higher-performance chain.

The old chain is made up of segmented links (figure B) that ride on the teeth of the crankshaft and camshaft sprockets. By contrast, the new chain (figure C) has rollers built into each link that fit like a glove on the dual rows of teeth in the new gears. The replacement crankshaft gear (figure D) has three separate key-ways. These may be used for adjusting engine performance by advancing or retarding the engine timing. It also has two rows of teeth for better grip.

Installation Procedure

• First, the crankshaft seal (aka, the "front seal") -- located in the front engine cover that was removed earlier -- needs to be replaced with a new one. Pull out the old seal using a seal-puller or, if necessary, tap it out using a hammer and punch.

• Use a rag to clean out the opening in the front cover where the seal was installed.

• Position the replacement seal on top of the opening (figure E) and tap it into position using a seal-installer (figure F).

  Important: Avoid simply tapping the seal into the opening with a hammer. This can damage the seal and could result in an engine leak and serious damage.

• With the engine cover, chain and sprockets removed, clean the front portion of the engine. As a precaution, use a lint-free shop-rag to block the front access area of the oil-pan (figure G) to prevent debris from entering the oil pick-up or contaminating the oil.

• Install the new crank gear (figure H), making certain that it is oriented properly. You may need to use a hammer and blunt punch to tap the gear into position and seat it securely.

• Before installing the new chain, soak it in engine oil. This will ensure proper lubrication from the moment that the engine is started, following the installation.

• Place the chain on the gear (figure I), making certain that the alignment mark is at the 6-o'clock position, and slide the assembly into place.

• Install the bolts that hold the gear and chain in place (figure J). These bolts need to be torqued to proper specification -- in our case, only 20 foot-pounds. (Over-tightening the bolts could strip the threads and cause serious damage to the camshaft.)

  
  

• The next step is to replace the front engine-cover gasket. Always replace old gaskets; never re-use them even if they look OK. Gaskets are inexpensive -- much less expensive than the cost of subsequent repairs if worn ones should fail.

  
  

• Apply gasket sealer to the mating surface of the engine (figure K), making certain to apply a good, even layer.

  
  

• Install the new gasket, making certain to install it with the correct side facing up.

  
  

• Apply gasket sealer to the top of the gasket (figure L).

  
  

• Reinstall the engine cover, and bolt it on securely.

  
  

• Position the harmonic balancer back in place on the engine cover (figure M ) and secure it using a harmonic-balancer installing tool (figure N). Tighten down the nut until the balancer is snug.

  
  

• Install the pulley, and tighten down the mounting bolts securely.

  
  

• Install the harmonic-balancer bolt in the center of the pulley (figure O). (In our case we had to install a new one, since the original one was missing from the vehicle.)

In the segment that follows, the remainder of the removed parts (or replacement parts) are installed on the vehicle to complete the project.

RESOURCES :

The Complete Idiot's Guide to Trouble-Free Car Care
Author: Dan Ramsey
ISBN: 0028635833
Alpha Books

How Cars Work
Author: Tom Newton
ISBN: 0966862309
Publisher: Black Apple Press

Auto Repair for Dummies
Author: Deanna Sclar
ISBN: 0764550896