Removal & Installation
- Disconnect the negative battery cable. Drain the cooling system and crankcase.
- Remove the timing chain/engine front cover and water pump as an assembly. For details, please refer to the timing chain cover procedure located earlier in this section.
- Remove the camshaft sprocket bolt and washer from end of the camshaft.
- Remove the distributor drive gear.
- Remove the camshaft sprocket, crankshaft sprocket, and timing chain.
If the crankshaft sprocket is difficult to remove, carefully pry to sprocket off the shaft using a pair of large prybars positioned on both sides of the crankshaft sprocket.
- Remove the chain tensioner assembly from the front of the cylinder block. This is accomplished by pulling back on the ratcheting mechanism and installing a pin through the hole in the bracket to relieve tension.
The front cover houses the oil pump. If a new front cover is to be installed, remove the water pump and oil pump from the old front cover.
- Lightly oil all bolt and stud threads before installation. Clean all gasket surfaces on the front cover, cylinder block, and fuel pump. If reusing the front cover, replace crankshaft front oil seal.
If a new front cover is to be installed, complete the following:
- Install the oil pump gears.
- Clean the water pump gasket surface. Position a new water pump gasket on the front cover and install water pump. Install the pump attaching bolts and tighten to 15-22 ft. lbs. (20-30 Nm).
- Rotate the crankshaft as necessary to position piston No. 1 at TDC and the crankshaft keyway at the 12 o' clock position.
- Install the tensioner assembly. Make sure the ratcheting mechanism is in the retracted position with the pin pointing outward from the hole in the bracket assembly. Tighten the retaining bolts to 6-10 ft. lbs. (8-14 Nm).
- Lubricate timing chain with clean engine oil. Install the camshaft sprocket, crankshaft sprocket, and timing chain.
- Remove the pin from the tensioner/vibration damper assembly to load the timing chain vibration damper arm against the timing chain. Make certain the timing marks are positioned across from each other.
- Install the distributor drive gear.
- Install the camshaft sprocket washer and bolt at the end of the camshaft, then tighten to 30-37 ft. lbs. (41-50 Nm).
- Install the timing chain/engine front cover, using a new gasket. For details regarding this procedure, please refer to timing chain cover removal and installation earlier in this section.
- Connect battery ground cable. Start the engine and check for leaks.
This is not a free wheeling engine. If it has "jumped time," there will be damage to the valves and/or pistons and will require the removal of the cylinder heads.
The camshafts and/or crankshaft must never be rotated when the cylinder heads are installed and the timing chain is removed. Failure to heed this warning will result in valve and/or piston damage.
- Disconnect the negative battery cable.
- Remove the valve covers and the timing chain front cover.
- Remove the crankshaft position sensor tooth wheel.
- Rotate the engine to set the No. 1 piston at TDC on the compression stroke.
- Install cam positioning, on the flats of the camshaft. This will prevent accidental rotation of the camshafts.
- Remove the 2 bolts retaining the right tensioner to the cylinder head and remove the tensioner. Remove the right tensioner arm.
- Remove the 2 bolts retaining the right chain guide to the cylinder head and remove the chain guide. Remove the right chain and right crankshaft sprocket. If necessary, remove the right camshaft sprocket retaining bolt, washer, sprocket, and spacer.
Cam positioning tools must be installed on the camshaft to prevent the camshaft from rotating.
- Remove the 2 bolts retaining the left tensioner to the cylinder head and remove the tensioner. Remove the left tensioner arm.
- Remove the 2 bolts retaining the left chain guide to the cylinder head and remove the chain guide. Remove the left chain and left crankshaft sprocket. If necessary, remove the left camshaft sprocket retaining bolt, washer, sprocket, and spacer.
Cam positioning tools, must be installed on the camshaft to prevent the camshaft from rotating.
- Inspect the friction material on the tensioner arms and chain guides. If worn or damaged, remove and clean the oil pan and replace the oil pickup tube.
Do not rotate the crankshaft and/or camshafts.
- Make sure cam positioning tools, are installed on the camshafts to prevent them from rotating.
- If removed, position the camshaft spacers and sprockets on the camshafts and install the washers and retaining bolts. Do not tighten at this time.
- Install the left crankshaft sprocket with the tapered part of the sprocket facing away from the engine block.
The crankshaft sprockets are identical. They may only be installed 1 way, with the tapered part of the sprocket facing each other.
- Install the left timing chain on the camshaft and crankshaft sprockets. Make sure the copper links of the chain line up with the timing marks of the sprockets.
If the copper links of the timing chain are not visible, pull the chain taught until the opposite sides of the chain contact one another and lay it on a flat surface. Mark the links at each end of the chain and use them in place of the copper links.
- Install the right crankshaft sprocket with the tapered part of the sprocket facing the left crankshaft sprocket.
- Install the right timing chain on the camshaft and crankshaft sprockets. Make sure the copper links of the chain line up with the timing marks of the sprockets.
It is necessary to bleed the timing chain tensioners before installation. Proceed as follows:
- Position the timing chain tensioner in a soft-jawed vice.
- Using a small pick or similar tool, hold the ratchet lock mechanism away from the ratchet stem and slowly compress the tensioner plunger by rotating the vise handle.
The tensioner must be compressed slowly or damage to the internal seals will result.
- Once the tensioner plunger bottoms in the tensioner bore, continue to hold the ratchet lock mechanism and push down on the ratchet stem until flush with the tensioner face.
- While holding the ratchet stem flush to the tensioner face, release the ratchet lock mechanism and install a paper clip or similar tool in the tensioner body to lock the tensioner in the collapsed position.
- The paperclip must not be removed until the timing chain, tensioner, tensioner arm and timing chain guide is completely installed on the engine.
- Install the right and left timing chain tensioners and secure with 2 bolts on each. Tighten the bolts to 15-22 ft. lbs. (20-30 Nm).
- On 1993 and later vehicles, install a crankshaft positioning tool, over the crankshaft and front cover alignment dowel, to position the crankshaft.
- Lubricate the tensioner arm contact surfaces with engine oil and install the right and left tensioner arms on their dowels.
- Install the right and left timing chain guides and secure with 2 bolts on each. Tighten the bolts to 6-9 ft. lbs. (8-12 Nm).
- Position a suitable C-clamp around the tensioner arm and chain guide, to remove all slack from the chain.
- Remove the paper clips from the timing chain tensioners and make sure all timing marks are aligned.
- Using a camshaft positioning tool, align the camshaft, tighten the camshaft sprocket-to-camshaft bolt to 81-95 ft. lbs. (110-130 Nm).
- On 1993 and later vehicles, position a suitable dial indicator in the No. 1 cylinder spark plug hole. Check that the camshaft is at maximum lift for the intake valve when the piston is at 114° after TDC. If it is not, loosen the camshaft sprocket bolt and repeat Steps 18-22.
- Remove the camshaft and crankshaft positioning tools.
- Installation of the remaining components is the reverse of removal.
- Connect the negative battery cable, start the engine and check for leaks and proper operation.
- Disconnect the negative battery cable and drain the cooling system.
Never open, service, or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. In addition, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.
- Remove the timing chain front cover.
- Rotate the crankshaft until the timing marks on the sprockets are aligned.
- Remove the camshaft retaining bolt, washer, and eccentric. Slide both sprockets and the timing chain forward and remove them as an assembly.
- Position the sprockets and timing chain on the camshaft and crankshaft simultaneously. Make sure the timing marks on the sprockets are aligned.
- Install the washer, eccentric, and camshaft sprocket-retaining bolt. Tighten the bolt to 40-45 ft. lbs. (54-61 Nm).
- Install the timing chain front cover and remaining components.
- Fill the cooling system. Connect the negative battery cable, start the engine, and check for leaks.
- Check and adjust the ignition timing and idle speed, as necessary.