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How to: SOHC V6 Timing Chain Inspection & Repair

Discussion in 'Under the Hood' started by 2000StreetRod, July 28, 2010.

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  1. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Background

    The SOHC V6 timing chain related components can fail as early as 45,000 miles and as late as 250,000 miles depending on component improvements incorporated in the year of manufacture, vehicle maintenance, driving habits, and just luck. Various years and models of Explorers, Mountaineers, Rangers, Mustangs and Discovery III vehicles were produced with Ford's SOHC V6. Ford recognized a few years after the first 1997 SOHC V6 model was sold that there were problems with the durability of the original tensioners and guides. Various upgrades were incorporated between 1997 and 2002. The 3 leaf spring primary (crankshaft to jackshaft) timing chain tensioner was replaced with a larger base, 6 leaf spring unit. The wear resistance of the various guides was improved. The left guide assembly was reinforced with metal on the chain traction and slack sides. The right guide assembly was reinforced with metal on the chain slack side. The left and right spring/hydraulic tensioners were improved.

    Failure of the primary timing chain tensioner or guide normally does not result in engine damage. It only affects camshaft timing relative to the crankshaft due to slack in the primary chain. However, if both the tensioner and guide are failed, it is possible that the chain could slip enough that the pistons and valves on both banks could collide.

    Failure of the camshaft timing chain guide assembly can result in the chain slipping. When it slips, it frequently slips enough that the exhaust valves collide with the pistons on that bank as shown in the photo below by cjmedina.
    3Dings.jpg

    It is difficult to identify by sound which timing chain related components have failed. The dreaded timing chain rattle echoes within the engine making isolation uncertain even when using a mechanic's stethoscope. Timing chain rattle can occur at engine start, at mid-range engine speeds, or may start and stop seemingly at random. The rattle could be due to weak or broken spring or hydraulic tensioners, broken or excessively worn plastic guides, worn chains or worn sprockets. Normally, the chains and sprockets are functional significantly longer than the tensioners and guides.

    The only reliable method of determining the source of timing chain rattle is visual inspection. The upper sections of the left and right guide assemblies can be inspected after removal of the valve covers (requires removal of the upper intake manifold). The primary tensioner and guide and the lower section of the left guide assembly can be inspected after removal of the front timing cover.

    Since the right guide assembly can only be replaced by removing the engine (or the transmission) I recommend checking it first. If broken, you may decide to replace (rather than repair) the engine. There's no point finding what else may be wrong if it's not going to be repaired. Next, the left valve cover should be removed and the left guide assembly inspected. If it's broken then the front timing cover will have to be removed to replace it. If it's not broken then the timing chain rattle is coming from under the timing cover. The original style primary tensioner frequently fails before the left guide assembly.
     
    Last edited: July 29, 2010
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  3. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Right guide assembly inspection

    Note: It is important to position the crankshaft with #1 piston at TDC on the compression stroke prior to removing the crankshaft balancer or either camshaft sprocket retaining bolt. Special tools are required to determine TDC once the crankshaft balancer with crankshaft timing marks is removed. The SOHC V6 is an interference engine and rotating the crankshaft or either camshaft when a camshaft sprocket is loose risks valve to piston collision.

    Inspecting the right timing chain guide assembly with the engine in the vehicle is rather difficult because of limited access. The hood prevents direct viewing from above and the heater blower box prevents viewing from the side. The use of a rectangular mirror at an angle may help. Taking photos with a camera may provide additional visibility. The photo below by CDW6212R shows a good guide assembly.
    Projectthread058.JPG

    Sometimes the upper section of the traction side (the side with no tensioner) will be completely missing since it has no metal reinforcement and is susceptible to fatigue failure. See photo below.
    SlckRt.jpg
    The guide assembly upper mounting bolt may be flat on one side due to the chain slapping against it. Or, the guide assembly may appear to be intact but the lower section is separated from the upper section as shown in the photo below by cjmedina.
    DSCN8608.jpg
    This can be detected by pulling upward on the traction side of the guide assembly. If it moves a quarter inch or more then it is broken. If there is considerable slack in the chain at the camshaft sprocket then the guide assembly is probably broken or the spring in the hydraulic tensioner is broken.

    The slack side (the side with the hydraulic tensioner) of the right guide assembly does not usually break on later models because of it's metal reinforcement.
     
    Last edited: July 29, 2010
  4. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Left guide assembly inspection

    Note: It is important to position the crankshaft with #1 piston at TDC on the compression stroke prior to removing the crankshaft balancer or either camshaft sprocket retaining bolt. Special tools are required to determine TDC once the crankshaft balancer with crankshaft timing marks is removed. The SOHC V6 is an interference engine and rotating the crankshaft or either camshaft when a camshaft sprocket is loose risks valve to piston collision.

    Inspection of the upper section of the left guide assembly is fairly easy because it is located at the front of the engine with good access.

    The photo below by shelbygt shows the slack side of the guide assembly to be intact.
    tensioner0.jpg

    The photo below by shelbygt shows the failed traction side of the guide assembly.
    tensionplastic.jpg
    The camshaft sprocket was detached for inspection.

    The photo below by gold984by4 is another example of a failed guide assembly on the traction side.
    ResizeofPICT0726.jpg

    If the engine contains excess sludge as shown below inspection may be a little difficult.
    CamLt.jpg

    With the original style guide assembly either side (traction or slack) could be broken due to fatigue failure. With the upgraded guide assembly the plastic protrusion that contacts the hydraulic tensioner may be broken off. Excess slack in the chain at the camshaft sprocket indicates a problem with either the guide assembly or the hydraulic tensioner spring. The plastic sections of the guide are attached to the metal reinforcement with plastic clips instead of bonding. The plastic clips can break allowing vertical movement of the plastic that contacts the chain. Or the plastic may fracture leaving only the metal sections in position.
     
    Last edited: July 31, 2010
  5. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Under timing cover inspection

    Note: It is important to position the crankshaft with #1 piston at TDC on the compression stroke prior to removing the crankshaft balancer or either camshaft sprocket retaining bolt. Special tools are required to determine TDC once the crankshaft balancer with crankshaft timing marks is removed. The SOHC V6 is an interference engine and rotating the crankshaft or either camshaft when a camshaft sprocket is loose risks valve to piston collision.

    Removal of the front timing cover (which requires crankshaft balancer removal) allows inspection of the primary chain (crankshaft to jackshaft) tensioner and guide, lower section of left guide assembly, and balancer shaft tensioner and guide if equipped (usually on 4WD models). It is not necessary to remove the water pump. The front cover can be removed with the water pump attached as an assembly. It is not necessary to remove the cranskhaft position sensor. Just be careful it is not damaged when setting the front cover aside.

    Loosening of the crankshaft balancer retaining bolt and removal of the crankshaft balancer is somewhat involved due to the tightness of the bolt and the depth of the balancer. The process will be described here.

    The 19mm hex head M12-1.5 crankshaft balancer retaining bolt is a torque-to-yield bolt that should not be reused. When it is installed it is torqued to 37 ft-lbs and then rotated an additional 90 degrees. This is equivalent to more than 100 ft-lbs. The easiest way to loosen the bolt is with an impact wrench but that usually requires removal of the radiator for access. Also, the SOHC V6 engine timing chains are susceptible to slipping when the engine is rotated counter-clockwise. Another method that some members have used is to install a large breaker bar with socket onto the retaining bolt and wedge the bar in position against the floor or vehicle structural member. Then the starter motor is engaged for just an instant. This method does not risk slipping the timing chain but is rather uncontrolled. A third method is to use a strap wrench attached to the smaller diameter section of the balancer (but not on the timing teeth) to hold the crankshaft from rotating while a breaker bar loosens the balancer bolt. This is the most controlled method but a suitable strap wrench may be expensive and difficult to locate. A fourth (and more crude) method is to utilize a deep jaw pipe wrench. The diameter of the narrow section of the balancer is greater than 4 inches so the depth of the pipe wrench jaws must be greater than 2 inches. It is very important that the jaws do not contact the balancer timing teeth. If they are damaged the engine may not start or run properly. The area between the green arrows in the photo below is where the strap or pipe wrench can be applied. Avoid the area between the red arrows.
    StrapIt.jpg

    A crankshaft balancer puller is required to remove the balancer. Do not attempt to use a gear puller. A gear puller will damage the rubber like material between the inner and outer sections of the balancer. Crankshaft balancer pullers usually come in a kit that includes various diameter and length bolts to attach the puller to the balancer. Because of the depth of the balancer the standard puller kit bolts will be too short. They may be long enough to engage but will strip when force is applied to the center puller bolt. Suitable bolts are M8-1.25 of 90mm or 100mm (preferred) length. Some members use the stud bolts that attach the A/C compressor to its mount.

    In order to remove the balancer the large bolt on the puller has to press against something contacting the crankshaft while the two smaller bolts pull against the balancer. See photo below by cjmedina.
    DSCN8621.jpg
    The normal process is to loosen the balancer retaining bolt about a half inch. Then install the puller with the center bolt pushing against the head of the balancer retaining bolt and the long side bolts attached to the balancer. The puller center bolt head is then alternately tightened with a wrench and hit with a hammer until the balancer is extracted far enough to reach the head of the balancer retaining bolt. Then the puller is removed, the balancer retaining bolt is loosened another half inch and the puller is reinstalled and the puller center bolt is tightened and hammered until the balancer once again reaches the head. The process is repeated until the balancer is free of the crankshaft or there are only a few balancer retaining bolt threads still engaged with the crankshaft. Then the balancer retaining bolt is completely removed and a longer bolt inserted. The longer bolt can be the same thread as the balancer retaining bolt but those are hard to find and expensive. Instead, I use a smaller diameter (3/8 inch) bolt that does not engage the female threads on the crankshaft and is long enough (5.5 inch) to seat in the bottom of the bore for the crankshaft threads. By this point there is little force required to complete the extraction of the balancer because there is only a small amount of surface in contact with the crankshaft.

    It is hammering the puller center bolt head (impulse) that results in extraction of the balancer. The side bolts just apply the tension determined by how much the center bolt is turned.

    If the front crankshaft seal is not leaking and the front cover is removed without damaging it, then replacement of the seal is not required prior to reassembly.

    To remove the front timing cover:
    1. Remove the 5 oil pan bolts (10mm) that attach to the cover
    2. Remove the 2 studs (10mm) at the bottom of the cover
    3. Remove the nuts attaching the crankshaft position sensor loom bracket
    4. Remove the loom bracket
    5. Remove the loom bracket studs
    6. Remove the nut attaching the vacuum rigid hose bracket
    7. Remove the vacuum hose assembly
    8. Remove the stud for the vacuum hose assembly
    9. Remove the thermostat housing
    10. Pry the cover loose from the block starting at the top and working downward
    11. Be careful not to move the cover up and down excessively deforming the crankshaft front seal
    12. Be careful not to damage the curved rubber section of the oil pan gasket.

    The photo below by CDW6212R shows a good (original style) primary tensioner and guide.
    SOHCvalvetrain.JPG
    Also visible in the lower left of the photo is the balance shaft guide. The balance shaft tensioner is below the guide and not visible because of the installed block cradle (upper pan).
     
    Last edited: August 1, 2010
  6. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Under timing cover inspection - continued

    Often it is obvious that the primary tensioner has failed as shown in the photo below by White98.
    Exp019.jpg
    However, in the case of leaf spring failure it may be necessary to attempt to deflect the primary chain to detect the failure. In the photo below the chain is deflected by the tensioner but still loose against it.
    PrimTens.jpg
    Even if the primary tensioner has not failed, if it is the original 3 leaf spring style with the small base I recommend replacing it with the 6 leaf spring style with the wide base as shown in the photo below by shelbygt.
    reassb.jpg

    The primary timing chain tensioner and guide may be replaced without retiming the camshafts since loosening or removal of the jackshaft sprocket is not required. If the jackshaft sprocket retaining bolt is loosened the camshafts must be retimed since the compressed valve springs may cause the camshafts and jackshaft to rotate. Normally, the OTC-6488 timing tool kit is required to retime the camshafts.

    With the front cover removed a small portion of lower section of the left guide assembly is visible. Make sure that the "finger" next to the lower sprocket is not broken as shown in the photo below by gold984by4.
    ResizeofPICT0743.jpg
    I suspect it assists in oiling the chain when the engine is running. Restricted access to the left guide assembly lower mounting bolt is also available.

    I have no first hand experience with the balance shaft tensioner or guide. I believe the guide is easily replaced but replacement of the tensioner may require removal of the block cradle (upper oil pan).
     
    Last edited: July 30, 2010
  7. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Primary tensioner & guide replacement

    Note: Replacement of the primary (crankshaft to jackshaft) chain tensioner and guide can be easily accomplished with the engine in the vehicle and does not require loosening the jackshaft sprocket retaining bolt. Therefore, retiming of the camshafts is not required.

    Remove the two bolts (8 mm) attaching the primary chain tensioner to the block.

    Slide the tensioner toward the passenger side of the engine until it is clear of the chain and can be removed.

    Remove the two bolts (10 mm) attaching the primary chain guide to the block.

    Pull the guide forward until it is free of the block. There is a guide pin on the rear of the guide that keeps it from moving up, down, left or right. The guide pin actually plugs into an oil port identified by the green arrow in the photo below.
    JackKeep.jpg

    Install new guide making sure guide pin seats in block.

    Install new guide mounting bolts (10 mm) and torque (14 ft-lbs).

    Position new tensioner.

    Install tensioner mounting bolts (8 mm) and torque (80 in-lbs).

    Extract tensioner leaf spring holding pin.

    Make sure that primary chain is in tension.
     
    Last edited: August 10, 2010
  8. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Left timing chain cassette replacement - with OTC-6488

    This post describes how to replace the left timing chain cassette (or just the guide assembly) after the left valve cover and front timing cover have been removed. It assumes the OTC-6488 tool kit will be utilized to retime the camshafts.

    Note: The left cassette lower chain and sprocket are located below the jackshaft sprocket. In order to replace the left cassette the jackshaft sprocket retaining bolt and sprocket must first be removed. When the jackshaft sprocket retaining bolt is loosened the left and right camshaft timing is lost because the valve spring pressure exerted on the camshafts may cause them to rotate.

    Make sure #1 piston is at TDC on the compression stroke. The protrusion (nub) on the left camshaft for the camshaft position sensor should be on upper side of the camshaft.

    Remove the primary tensioner as described in the previous post.

    Install camshaft gear holding tool (6478) and camshaft gear holding tool adapter (6482) onto the left camshaft sprocket. The photo below by shelbygt shows the left camshaft in the correct position with the tools installed.
    tools1.jpg

    Loosen (counter-clockwise) and remove jackshaft sprocket retaining bolt using female star socket E18

    Loosen (counter-clockwise) the left camshaft sprocket retaining bolt (19mm)

    Note: After a few hours of operation wear patterns develop on the sprockets and chain. Keep the sockets and chain together as an assembly to preserve the wear patterns.

    Mark the front side of the crankshaft sprocket.

    Grasp the jackshaft sprocket and chain with one hand and the crankshaft sprocket and chain with the other hand and pull sprockets and chain forward as an assembly. Pinch the chain together and wrap with a large rubber band to keep the chain in place around each sprocket.

    The photo below by CDW6212R shows the lower section of the cassette after removal of the primary chain and sprockets assembly.
    Projectthread067.JPG

    Remove the camshaft gear holding tool (6478) and camshaft gear holding tool adapter (6482) from the left camshaft sprocket.

    Remove the cassette upper mounting torx bolt using T30 bit.

    Remove the cassette lower mounting bolt (10mm).

    Remove the camshaft sprocket retaining bolt (19mm).

    Extract the cassette from the head.

    Carefully insert the new cassette into the head. Do not break the lower "finger" on the guide assembly.

    Position the camshaft sprocket onto the camshaft and loosely install the camshaft sprocket retaining bolt.

    Loosely install the cassette lower mounting bolt (10mm).

    Install the cassette upper mounting bolt using T30 bit and torque (9 ft-lbs)

    Torque the cassette lower mounting bolt (10mm). (14 ft-lbs)

    Install the primary chain and sprockets assembly with the crankshaft sprocket mark facing forward. The photo below by CDW6212R shows the front of the crankshaft sprocket.
    CrankgearFront.JPG

    Install camshaft gear holding tool (6478) and camshaft gear holding tool adapter (6482) onto the right camshaft sprocket.

    Install the new jackshaft sprocket retaining bolt using female star socket E18 and torque (33 ft-lbs + 90 degrees)

    Remove the camshaft gear holding tool (6478) and camshaft gear holding tool adapter (6482) from the right camshaft sprocket.

    Install the primary tensioner as described in the previous post.
     
    Last edited: August 1, 2010
  9. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Engine assembly

    It is probable that the plastic pieces from failed timing chain components will reside in the bottom of the oil pan and lodged in the oil pickup tube screen. The oil pan and pickup tube screen should be removed and cleaned. I'm not aware of any way to separate the screen from the tube. My method was to use a T30 torx bit to remove the two bolts that attach the pickup tube to the oil pump as shown in the photo below.
    PrimeOil.jpg

    Then I carefully separated the pickup tube from the pump without tearing the gasket between them. I cleaned the screen with engine flush and then used a bent wire to loosen the plastic fragments lodged between the outer diameter of the screen and its enclosure. While holding the pickup tube with the screen opening downward I shook it from side to side until the fragments fell out. I applied gasket sealer to the old gasket just prior to reinstalling the oil pickup tube.

    Install oil pan with gasket.

    Apply silicone gasket and sealant to the exposed oil pan front and the engine block mating surfaces.

    Apply silicone gasket and sealant to the front cover in two places.

    Apply engine oil to crankshaft front seal.

    Loosely install the engine front cover with new gasket.

    Loosely install crankshaft balancer.

    Slide front cover from side to side and up and down to align front crankshaft seal with balancer.

    Tighten cover upper bolts (14 lb-ft).

    Install engine front cover lower bolts and tighten (14 lb-ft).

    The new crankshaft damper retaining bolt is not long enough to reach the crankshaft when the damper is first positioned on the crank. Ford uses a special tool to install the damper. The photo below shows my "special tool" consisting of an on hand 36mm 6 point socket and a 4 lb hand sledge hammer.
    DampTool.jpg
    The socket is larger in diameter than the damper retaining bolt head and it's round seat. I "tapped" the socket with the hammer until the damper was far enough onto the crankshaft that the new retaining bolt could screw in at least a half inch to eliminate the possibility of stripping its threads. I continued tapping and screwing until the damper was seated on the crank.

    Install a strap (chain or pipe) wrench to smaller diameter of balancer avoiding crankshaft position sensor timing teeth.

    While preventing rotation of crankshaft with strap wrench, torque new balancer bolt to 44 ft-lbs +90 degrees

    Remove strap wrench
     
    Last edited: August 1, 2010
  10. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Camshaft timing using OTC-6488

    This post describes timing of the camshafts after repair of the primary and left timing chain related components using the OCT-6488 tool kit shown below.
    toolkit.JPG
    The tools are indexed as follows:
    1 - 6485, camshaft gear bolt socket
    2 - 6485, camshaft gear bolt socket extension
    3 - 6481, camshaft holding tool
    4 - 6478, camshaft gear holding tool
    5 - 6484, timing chain tensioner tool with O ring
    6 - 6480, camshaft holding tool adapter
    7 - 6482, camshaft gear holding tool adapter
    8 - 6479, crankshaft holding tool
    9 - molded storage case

    Using breaker bar with 19mm socket installed on balancer bolt position #1 piston at TDC by aligning balancer mark with pointer.

    Note: Crankshaft holding tool (6479) must contact the engine block to keep #1 piston at TDC.

    While observing the timing mark on the balancer install the crankshaft holding tool (6479).

    Check the timing of right camshaft by attempting to install camshaft holding tool (6481) and camshaft holding tool adapter (6480) onto the right camshaft. If the adapter will not install due to misalignment then the right camshaft will have to be timed as follows:

    Begin (Right camshaft timing procedure)

    Install camshaft sprocket holding tool 6478 and adapter 6482 onto the right hand camshaft sprocket. Tighten the top two clamp bolts of the camshaft sprocket holding tool to 10 Nm (89 lb-in).

    Caution: The right hand camshaft sprocket bolt is a left-hand threaded bolt (tightens counter-clockwise).

    Using camshaft gear removal tool 6485 loosen the right hand camshaft sprocket bolt. Loosen the top bolts of camshaft sprocket holding tool 6478.

    Note: The camshaft timing slots are off center. Position the camshaft timing slots below the centerline of the camshaft. This will allow for proper installation of camshaft holding tool 6481 and adapter 6480 onto the cylinder head. Then, install both tools onto the cylinder head.

    Remove the right hand camshaft timing chain tensioner and install timing chain tensioner tool 6484.

    Caution: The right hand camshaft sprocket bolt is a left hand threaded bolt.

    Note: If camshaft gear removal tool 6481 is being used with the torque wrench, keep the torque wrench in line with the tool and tighten the camshaft sprocket to 61 Nm (45 lb-ft), (this tool will amplify the torque). Otherwise, tighten the camshaft sprocket to 85 Nm (63 lb-ft).
    Tighten the top two clamp bolts on camshaft sprocket holding tool 6478 to 10 Nm (89 lb-in).
    Tighten the camshaft sprocket bolt to 85 Nm (63 lb-ft).

    Remove timing chain tensioner tool 6484 and install the right hand camshaft timing chain tensioner.
    If installing the original washer, tighten to 67 Nm (49 lb-ft).
    If installing a new washer, tighten to 44 Nm (32 lb-ft).
    Apply grease to the washer to keep it in position until tight.

    Remove all special tools from the right hand cylinder head.
    End (Right camshaft timing procedure)

    Begin (Left camshaft timing procedure)

    Install camshaft sprocket holding tool 6478 and adapter 6482 onto the left hand camshaft sprocket. Tighten the top two clamp bolts of the camshaft sprocket holding tool to 10 Nm (89 lb-in).

    Using camshaft gear removal tool 6485 loosen the left hand camshaft sprocket bolt. Loosen the top bolts of camshaft sprocket holding tool 6478.

    Note: The camshaft timing slots are off center. Position the camshaft timing slots below the centerline of the camshaft. This will allow for proper installation of camshaft holding tool 6481 and adapter 6480 onto the rear of the left cylinder head. Then, install both tools onto the cylinder head.

    Remove the left hand camshaft timing chain tensioner and install timing chain tensioner tool 6484.

    Tighten the top two clamp bolts on camshaft sprocket holding tool 6478 to 10 Nm (89 lb-in).
    Tighten the camshaft sprocket bolt to 85 Nm (63 lb-ft).

    Remove timing chain tensioner tool 6484 and install the left hand camshaft timing chain tensioner.
    If installing the original washer, tighten to 67 Nm(49 lb-ft).
    If installing a new washer, tighten to 44 Nm 32 lb-ft).
    Apply grease to the washer to keep it in position until tight.

    Remove all special tools from the left hand cylinder head.
    End (Left camshaft timing procedure)

    Remove crankshaft TDC timing tool 6479 from the crankshaft.

    With oil pan installed, oil filter pre-filled, and oil in pan at full level rotate engine two revolutions using balancer bolt to check for interference and to prime oil pump.
     
    Last edited: August 1, 2010
  11. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Left guide replacement - no OTC-6488 use

    This post will describes replacement of the left timing chain guide assembly with no future use of the OCT-6488 tool kit. It assumes that the existing camshaft timing is correct (chain has not slipped). It should only be used if there was timing chain rattle but the engine ran good and the compression was good. This procedure should not be used if the compression of all cylinders on a bank is below normal which could be due to timing chain slip.

    Disclaimer: This procedure has not been validated. Use at your own risk! It is based on my SOHC V6 engine experience, a discussion I had with another member, and the following thread: Timing Chain Pictures!?!
    This procedure is provided here because the other member was determined to attempt something similar. If you implement this procedure, please provide positive or negative feedback so it may be improved for the benefit of other members.

    In general, the process consists of marking the left camshaft timing components relative to each other prior to disassembly in a manner that will allow restoration of their relative positions after replacement. It assumes that the front timing cover has been removed as described in previous post #4. It also assumes that the primary tensioner and guide has been replaced (if required) as described in previous post #6.

    The improvised tool shown in the photo below is suitable for preventing rotation of the jackshaft sprocket while tightening or loosening the jackshaft sprocket or camshaft sprocket retaining bolt. A scrap bolt with washers on both sides of the chain link is screwed into the head. Another scrap bolt with washers is passed thru a hole in the sprocket and chain link and secured with a nut.
    JSprkLsn.jpg
    The improvised tool is shown in the loosening configuration. For tightening the jackshaft sprocket or camshaft sprocket retaining bolts the chain is attached to the left head instead of the right head.

    Make sure #1 piston is at TDC on the compression stroke. The protrusion (nub) on the left camshaft for the camshaft position sensor should be on upper side of the camshaft.

    In order to remove the left guide assembly it is necessary to separate the camshaft sprocket from the camshaft. With a solvent clean the rear of the camshaft sprocket and the camshaft hub between the sprocket and the thrust bearing in an accessible location. Then make a line with a permanent marker to identify the relative position of the sprocket with the camshaft. After the ink has dried use an awl (or something similar) to scratch a line down the center of the ink line as shown in the photo below identified by the red arrow (right sprocket shown but left sprocket is identical).
    MarkHigh.jpg
    The scratch mark is more accurate then the ink and less likely to be accidently removed. This line is critical for aligning the sprocket with the camshaft.

    In order to remove the left guide assembly it is usually necessary to separate the camshaft sprocket from the chain. With solvent clean the front of the camshaft sprocket and chain in the vicinity of an accessible area. Also, clean the timing chain and block in the area between the jackshaft sprocket and the head. Mark lines with a permanent marker and an awl as identifed by the red arrows in the photo below.
    MarkLow.jpg
    The accuracy of these two lines is not critical since the teeth in the sprocket will align the chain when engaged.

    Install the improvised tool described above to prevent the jackshaft sprocket from rotating counter-clockwise (chain attached to right head with bolt).

    Loosen (counter-clockwise) the left camshaft retaining bolt (19 mm).

    Remove the improvised tool.

    Remove the cassette upper mounting torx bolt using T30 bit.

    Using a 10 mm box wrench loosen the cassette lower mounting bolt as shown in the photo below by gold984by4.
    ResizeofPICT0736.jpg
    When the bolt is loose it will be necessary to feed it thru a hole in the jackshaft sprocket to extract it. Use a magnet to keep it from falling.

    Important: When the camshaft sprocket bolt is removed it is important to prevent the chain from being so slack on the lower cassette sprocket (under the jackshaft sprocket) that the cassette sprocket teeth and the chain no longer engage. If the chain slips on the lower cassette sprocket it may be difficult to reposition the chain on the sprocket correctly so that the chain mark aligns with the block mark.

    Remove the camshaft sprocket retaining bolt.

    Separate the camshaft sprocket from the chain and lay the sprocket aside within reach.

    Carefully remove the left guide assembly.

    Carefully insert the new guide assembly. It may be necessary to bend the "finger" slightly to position the guide. Be careful not to break it.

    Install the chain unto the camshaft sprocket with the marks aligned.

    Check the alignment marks on the chain and the block in the area between the jackshaft sprocket and the head. If they are not aligned then the chain slipped a tooth on the lower sprocket. Slacken the chain and rotate it until the marks align.

    Position the camshaft sprocket with chain onto the camshaft and loosely install the camshaft sprocket retaining bolt.

    Loosely install the cassette lower mounting bolt (10mm).

    Install the cassette upper mounting bolt using T30 bit and torque (9 ft-lbs).

    Torque the cassette lower mounting bolt (10mm). (14 ft-lbs)
     
    Last edited: August 3, 2010
  12. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Left camshaft timing - no OTC-6488 use

    This post describes timing the left camshaft without using the OTC-6488 tool kit after replacement of the left guide assembly.

    Note: It is possible to determine TDC when the balancer is not installed by using a Prototype Manometer TDC finder

    After the guide assembly is installed comes the tedious and time consuming task of tightening the camshaft sprocket retaining bolt to the specified torque with the mark on the sprocket aligned with the mark on the camshaft hub. The problem is that as the bolt is tightened the chain becomes taught. As the chain becomes taught the hydraulic tensioner piston compresses allowing the chain and sprocket to rotate. If the camshaft rotates with the sprocket and the marks stay aligned then everything is fine. However, if the sprocket mark moves relative to the camshaft mark then the bolt must be loosened (not easily done) and the tightening process must be repeated. Adjustable locking pliers may be attached to the camshaft between the lobes and bearing caps to control the rotation of the camshaft during the tightening process. One good thing about the left camshaft is when #1 piston is at TDC on the compression stroke there is not a lot of valve spring pressure on the camshaft lobes.

    Install the improvised tool (chain and bolts) between the jackshaft sprocket and the left head.

    Install adjustable locking pliers on the camshaft between the lobes and bearing caps.

    Install torque wrench with 19mm socket onto the camshaft sprocket retaining bolt.

    Align the sprocket mark with the camshaft mark using the torque wrench and adjustable locking pliers as levers.

    Slowly tighten (clockwise) the camshaft sprocket retaining bolt (19mm) with the torque wrench (while maintaining alignment of the marks using the adjustable locking pliers) to 63 ft-lbs.

    Remove the improvised tool from the jackshaft sprocket.

    Remove the adjustable locking pliers.
     
    Last edited: August 3, 2010
  13. 2000StreetRod

    2000StreetRod Staff Member Moderator Elite Explorer

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    Engine assembly - no OTC-6488 use

    This post describes engine assembly after timing the left camshaft without using the OTC-6488 tool set.

    It is probable that the plastic pieces from failed timing chain components will reside in the bottom of the oil pan and lodged in the oil pickup tube screen. The oil pan and pickup tube screen should be removed and cleaned. I'm not aware of any way to separate the screen from the tube. My method was to use a T30 torx bit to remove the two bolts that attach the pickup tube to the oil pump as shown in the photo below.
    PrimeOil.jpg

    Then I carefully separated the pickup tube from the pump without tearing the gasket between them. I cleaned the screen with engine flush and then used a bent wire to loosen the plastic fragments lodged between the outer diameter of the screen and its enclosure. While holding the pickup tube with the screen opening downward I shook it from side to side until the fragments fell out. I applied gasket sealer to the old gasket just prior to reinstalling the oil pickup tube.

    Install oil pan with gasket.

    Apply silicone gasket and sealant to the exposed oil pan front and the engine block mating surfaces.

    Apply silicone gasket and sealant to the front cover in two places.

    Apply engine oil to crankshaft front seal.

    Loosely install the engine front cover with new gasket.

    Loosely install crankshaft balancer.

    Slide front cover from side to side and up and down to align front crankshaft seal with balancer.

    Tighten several front cover bolts until snug.

    Check balancer mark and pointer for TDC alignment.

    Check left camshaft timing slot next to firewall for correction orientation as shown in photo below by shelbygt.
    cam1.jpg
    The slot is below the camshaft centerline and is parallel to the head surface that mates with the valve cover.

    Tighten cover upper bolts (14 lb-ft).

    Install engine front cover lower bolts and tighten (14 lb-ft).

    The new crankshaft damper retaining bolt is not long enough to reach the crankshaft when the damper is first positioned on the crank. Ford uses a special tool to install the damper. The photo below shows my "special tool" consisting of an on hand 36mm 6 point socket and a 4 lb hand sledge hammer.
    DampTool.jpg

    The socket is larger in diameter than the damper retaining bolt head and it's round seat. I "tapped" the socket with the hammer until the damper was far enough onto the crankshaft that the new retaining bolt could screw in at least a half inch to eliminate the possibility of stripping its threads. I continued tapping and screwing until the damper was seated on the crank.

    Install a strap (chain or pipe) wrench to smaller diameter of balancer avoiding crankshaft position sensor timing teeth.

    While preventing rotation of crankshaft with strap wrench, torque new balancer bolt to 44 ft-lbs +90 degrees

    Remove strap wrench
     
    Last edited: August 3, 2010
  14. vipersinu2

    vipersinu2 Active Member

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    can you change harmonic balancer with out these tools? or will timing get messed up?
     
  15. TonyTiger2004

    TonyTiger2004 New Member

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    Balancer can be removed without Timing anything, It is Keyed. Be careful with your Camshaft Sensor though. Its the one Mounted right at the Balancer. You DO NOT want to hold your Ballancer where the grooves are. The sensor uses those grooves to check location of Crank. You will need a Harmonic Balancer Puller and 2 long M8 - 1.25 90mm or 100mm Bolts (preferably)

    See Photos Above On how to Remove.
     
  16. vipersinu2

    vipersinu2 Active Member

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    I was just wondering because I replaced my harmonic balancer, and spun the engine from the flywheel, without harmonic balancer in place, I was wondering if that can throw the cam timing off.
     
  17. TonyTiger2004

    TonyTiger2004 New Member

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    You should be fine. Long as you have not loosed any of the Timing Sprocket Bolts. The Balancer is keyed it will only go on one way. Just make sure the Crank Sensor is aligned up correctly.. The old engine i took out of my 98 Explorer Had breen rubbing the Balancer.
     
  18. HOODRICH77

    HOODRICH77 New Member

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    if any of the jackshaft chains or front and rear cassette chains jump a tooth or become loose do to damaged tentioners will it cause loud rattling or knocking sounds i know it would screw the timing but would that cause these sounds. other than the knocking or rattling noise the engine actually starts up right away and seems to run ok. im so confused on what the hell is going on with this engine. i know there is like 4 or 5 chains inside this engine. its a 97 explorer with 4.0 v-6 SOHC engine. Can some one please give me some insite on whats going on in there
     
  19. Arsenil

    Arsenil New Member

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    I have a question, can we replace those timing chain without taking appart the upper parts of the engine ? as shown on the pic N3 of my quote ?
     
  20. gladiatorxxx

    gladiatorxxx New Member

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    SOHC Oil Pump Drive

    Deleted
     
    Last edited: November 11, 2012
  21. lurker01

    lurker01 New Member

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    Just to add a little.
    Did not take engine out. Main tensioner broken as well as tensioner on balance shaft. Managed to get new balance shaft tensioner in without taking engine out. Took new spring off new base, notched the spring on the end that goes on the pin, bent old (still mounted) base down a little, installed new spring on old base (was not too easy, just be persistent), bent old base back into place. Did not take crank sprocket off either.
     

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