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How to: SOHC V6 Camshaft Timing

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2000StreetRod

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The SOHC V6 is an interference engine. If the valve timing relative to the crankshaft is excessively in error, pistons and valves may collide resulting in engine damage. The photo below by cjmedina shows the results of a slipped rear timing chain. The timing slipped 50 camshaft degrees and the exhaust valves struck the pistons.
3Dings.jpg

Accurate and correct camshaft timing is required for safe engine operation and to achieve designed engine performance.

There are no keys on the SOHC V6 jackshaft rear sprocket, the left camshaft sprocket nor the right camshaft sprocket. The sprockets are held in position entirely by the force exerted by their retaining bolts. There is a flat spot on the internal opposite sides of the jackshaft front flange (red arrows in photo below).
JackshaftD2.jpg

There are matching flats on the external shaft of the primary sprocket assembly but there is considerable rotational play between the primary sprocket shaft and the jackshaft flange. If the jackshaft front sprocket is loosened both camshafts should be retimed. If one of the camshaft sprockets is loosened then that camshaft must be retimed.

It is not possible to properly replace the front upper left timing chain or guide assembly without removing the jackshaft front sprocket. It may be possible to remove the left guide assembly pivot bolt without removing the jackshaft front sprocket but the bolt cannot be correctly torqued since access by a torque wrench is blocked by the jackshaft sprocket.

It is not possible to replace the rear upper right timing chain without removing the jackshaft rear sprocket. Since the cover for the jackshaft rear sprocket is behind the flexplate/flywheel, replacement of the rear cassette requires pulling either the engine or the transmission.

It is possible to replace the primary chain tensioner and guide without loosening the jackshaft front sprocket so no retiming is required. Replacing the primary chain requires removal of the jackshaft front sprocket and retiming of both camshafts.

Removing an engine head requires disconnecting the camshaft sprocket and subsequent retiming of the camshaft.

If a camshaft is removed for valve train work the camshaft must be retimed. Some valve train work is possible without camshaft removal but special tools may be required.

Requirements for accurate timing

The following list identifies the requirements to achieve accurate camshaft timing after all timing chain components and camshafts are installed on the engine.

1. The crankshaft must be locked in position (rotational motion in either direction prevented) with the #1 piston (right front of engine) at top dead center (TDC) on the compression stroke (intake and exhaust valves closed).

2. The jackshaft front and rear sprocket bolts must be tightened to the specified torque.

3.a. The right camshaft must be locked in position with the camshaft lobes for cylinder #1 not depressing the valves and the timing notch at the front of the camshaft below the camshaft centeline and parallel to the head surface that mates to the valve cover.

3.b. The traction side of the right timing chain must be taught (in tension).

3.c. The right camshaft sprocket bolt is torqued (tightens counter-clockwise) to 63 ft-lb (85 Nm)

4.a. The left camshaft must be locked in position with the camshaft position sensor protrusion above the camshaft centerline and the timing notch at the rear of the camshaft below the camshaft centeline and parallel to the head surface that mates to the valve cover.

4.b. The traction side of the left timing chain must be taught (in tension).

4.c. The left camshaft sprocket bolt is torqued (tightens clockwise) to 63 ft-lb (85 Nm)

Comments:

Some members have implemented creative methods to time their camshafts without purchasing the special timing kit OTC-6488. Unless a method to keep the chain taught when tightening the camshaft sprocket bolt is implemented the timing will not be accurate. The spring pressure provided by the normal spring/hydraulic tensioner is inadequate to tension the chain for timing. A bolt, washer and nut may be a suitable alternative for Timing Chain Tensioner Tool 303-571 (T97T-6K254-A) that is included with the timing kit.

Notes:

The camshaft sprocket bolts are not torque to yield and may be reused.

The jackshaft front and rear sprocket bolts are torque to yield and may not be reused.

The crankshaft damper bolt is a torque to yield and may not be reused.

The following tasks require separation of the engine and transmission. Accessibility to accomplish the task is significantly improved by pulling the engine rather than the transmission.
1. Rear timing chain replacement (requires flywheel/flexplate removal)
2. Rear timing chain guide assembly replacement
3. Jackshaft removal (requires flywheel/flexplate removal)
4. Jackshaft rear sprocket replacement (requires flywheel/flexplate removal)

Related Ford part numbers:

Jackshaft/primary timing chain kit 2U3Z6D256CA includes:
Crankshaft bolt harmonic balancer E7RY6A340B
Tensioner-engine jackshaft chain YL2Z6L266AA
Gasket-cylinder/timing front cover F77Z6020AB
Sprocket/gear-engine jackshaft/intermediate 2U3Z6M264AA
Guide-engine jackshaft chain 2L2Z6K297AA
Bolt-jackshaft sprocket bolt F77Z6M264BA superseded by 2L2Z6279AA (included when 2U3Z6M264AA is purchased)
Sprocket/gear-crankshaft two wheel drive 2L2Z6306BA
Chain-engine jackshaft F77Z6268AB
Bolt-camshaft sprocket right hand
Bolt-camshaft sprocket left hand F77Z6279BA

Left/front timing chain cassette assembly 7U3Z6A257A includes:
Timing chain
Guide assembly YL2Z6M273AA superseded by 7U3Z6A257A
Bolt-guide assembly upper mount
Sprocket/gear-camshaft
Sprocket/gear-jackshaft front

Right/rear timing chain cassette assembly 4L2Z6M290AA includes:
Timing chain
Guide assembly
Sprocket/gear-camshaft
Sprocket/gear-jackshaft rear

00M12 intake manifold kit YL2Z9E473AA includes:
Lower intake manifold gasket set of six YL2Z9461AA
Upper intake manifold gasket set of two YL2Z9E436AA
Left timing chain tensioner 7U3Z6K254B
Tensioner metal O ring XU2Z6M252AA
Oil restrictor
Galley plug

Right timing chain tensioner 7U3Z6K254A supersedes XU3Z6K254BA

Right timing chain guide assembly upper postioning bolt F77Z6U000BA

Jackshaft rear sprocket retaining bolt W703167S430

Cover assy/rear of block jackshaft opening plug F77Z6026AB

Left cassette assembly lower mounting bolt W500100S300

Jackshaft chain guide mounting bolt W500100S300

Sprocket/gear-crankshaft inner four wheel drive F77Z6306BE

Sprocket/gear - crankshaft outer four wheel drive 2L2Z6306AA

Balance shaft chain guide F77Z6K297BC

Balance shaft chain tensioner 1L2Z6L266AA

Balance shaft chain F77Z6268BC

Balance shaft assembly 1L2Z6A311AA

Seal-front timing cover E6TZ6700A was superseded by 5H2Z6700AA

Gasket set-valve cover F77Z6584AE

Gasket-lower oil pan 4L2Z6710AA year 2000+ F77Z6710BA year 1997-1999

Gasket-upper oil pan/reinforcement section F77Z6710AA

Left camshaft F7TZ6250AEE was superseded by 7L2Z6250D

Right camshaft F77Z6250AE

Exhaust manifold outlet bolts (M12-1.75X54.5 H) N811747S2
 



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OTC Ford Cam Tool Kit

The OTC Ford Cam Tool Kit is a special tool kit to time the SOHC V6 camshafts. It contains tool numbers 6478,6479, 6480, 6481, 6482, 6484, 6485, and a molded storage case as shown in the photo below.
OTC6488Kit.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
 






Thanks for doing this. I'm about to embark on a total rebuild of the SOHC engine, any and all info I can get my hands on is gonna save me some headaches in the future.


Si
 
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Cam timing procedure using OTC-6488

The following procedure is from the Ford service procedure for replacing the primary (jackshaft) timing chain components using the OTC-6488 tool kit. The procedure utilizes three other special tools (identified in bold) that are not included in the OTC-6488 tool kit. Because of the cost of the special tools, an alternative procedure utilizing improvised tools will be attempted and posted if successful.

Hold crankshaft from turning with special tool 303-674 or improvised tool and tighten the New jackshaft sprocket bolt in two stages:
Tighten the bolt to 45 Nm (33 lb-ft).
Tighten the bolt an additional 90 degrees.

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

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

Install the engine front cover, New front cover gasket, and upper bolts.

Tighten upper bolts to 19 Nm (14 lb-ft).

Install engine front cover lower bolts and tighten to 19 Nm (14 lb-ft).

Install crankshaft damper using crankshaft damper replacer 303-102.

Caution: The crankshaft damper bolt is torque to yield and must be replaced.

Install the New crankshaft damper bolt. Using strap wrench 303-D055 or alternative tool to hold the damper, tighten the New crankshaft damper bolt in two stages:
Tighten the bolt to 60 Nm (44 lb-ft).
Tighten the bolt an additional 90 degrees.

Caution: You must retime the left hand and right hand camshafts when either camshaft and/or the primary timing chain is disturbed.

Caution: It is important that the special tools be installed correctly. The engine can run badly, with one camshaft off by 180 degrees.

Caution: The following camshaft timing procedure must be performed exactly as written. Read this procedure carefully and thoroughly. This procedure includes information that has been updated from the workshop manual.

Note: Crankshaft TDC timing tool 6479 must contact the engine block. This positions the engine at TDC. While observing the timing mark on the damper, turn the crankshaft clockwise to position the number one cylinder at TDC and install crankshaft TDC timing tool 6479.
CrankshaftHolder.jpg

This will hold the crankshaft in position, and prepare the engine for cam timing.

Install camshaft sprocket holding tool 6478 and adapter 6482 onto the right hand camshaft sprocket.
CamshaftSprocketHolder.jpg

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.
cam1.jpg

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.
CamshaftHolder.jpg


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


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

Note: If camshaft gear removal tool 6485 (socket extension) 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).
SocketExtension.jpg

Otherwise, tighten the camshaft sprocket to 85 Nm (63 lf-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).

Remove all special tools from the right hand cylinder head.
 






Cam timing procedure using OTC-6488 (continued)

Install camshaft sprocket holding tool 6478 and adapter 6482 onto the left hand camshaft sprocket.
ToolsLft.jpg

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).

Remove all special tools from the left hand cylinder head.

Remove crankshaft TDC timing tool 6479 from the crankshaft.
 






Strap wrench 303-D055 alternative

The Ford camshaft timing procedure utilizes a special tool strap wrench 303-D055 (D85L-6000-A) to prevent the crankshaft harmonic balancer/damper from rotating when tightening the retaining bolt. The strap wrench is also utilized when loosening the harmonic balancer retaining bolt prior to removing the front timing cover.

If the engine is removed from the vehicle and the flexplate/flywheel is still attached, the improvised tool shown in the photo below is suitable for preventing rotation of the crankshaft while tightening or loosening the balancer retaining bolt. The improvised tool is shown in the balancer bolt tightening configuration.
ChanFlex.jpg

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 the torque converter/clutch mounting hole and secured with a nut. The configuration also allows easy loosening of the flexplate/flywheel crankshaft bolts.

The chain bolt is attached to the opposite side of the flexplate/flywheel when loosening the balancer bolt as shown below.
ChanBlnc.jpg

The configuration also allows easy tightening of the flexplate/flywheel crankshaft bolts.

If the engine is still in the vehicle then a pipe wrench may be a suitable alternative to using a strap wrench when tightening or loosening the crankshaft balancer bolt. A typical pipe wrench is shown in the photo below.
PipWrnch.jpg


The span between the jaws as identified by the green arrows must be at least 4 inches. The depth of the jaws as identified by the red arrows must be greater than 2 inches or the damper will hit the rear of the upper jaw adjustable support and the jaws will not grab properly. My 14 inch wrench with a 4 inch span between jaws was not deep enough to use. I measured the jaw depths of 18 inch, 21 inch and 24 inch pipe wrenches and none of them were greater than 2 inches.

The jaws should be applied in the area of the balancer identified with the green arrows in the photo below.
StrapIt.jpg

Avoid the area identified with the red arrows because of the indentations for the crankshaft position sensor. If these are damaged by the wrench the engine may not start or run properly. A bolt may be passed thru the end of the wrench and a chain. The other end of the chain may be bolted to the head to keep the wrench in position allowing one person to accomplish the task.
 






Crankshaft holder 303-674 alternative

The Ford camshaft timing procedure utilizes a special tool crankshaft holder 303-674 to prevent the crankshaft from rotating when tightening the jackshaft front sprocket retaining bolt. The improvised tool shown in the photo below is suitable for preventing rotation of the crankshaft while tightening or loosening the sprocket retaining bolt.
JSprkLsn.jpg

The improvised tool is shown in the loosening configuration. 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. For tightening the sprocket retaining bolt the chain is attached to the left head instead of the right head.
 






hello 2000streetrod
how are you
for the ohv is it same set-up as sohc \thank you :salute:
 






:usa:hello everybody what if i had a 4.0 ohc v-6 with ROCKER ARM SET-UP FROM FACTORY VIN X IT SET-UP LIKE OHV BUT BUT OHC WITH ROCKER ARM SET-UP
:salute:
 






No sir. The SOHC stands for "single over head cam" meaning there are two cams (one single cam per head) on top of the heads and above the valves. So if you take the valve cover off you'll see the cams.

The OHV stands for "Over head valve". This is more of the traditional style engine that everyone can relate too. If you take a valve cover off you'll see the valve springs and top of the valve.

Two different animals.
 






timining chain ohv or ohc v-6

hello everybody what if i had a 4.0 ohc v-6 with ROCKER ARM SET-UP FROM FACTORY VIN X IT SET-UP LIKE OHV BUT BUT OHC WITH ROCKER ARM SET-UP
 












Thanks 2000streetrod its clear to me now. i will try your method and i will give a feed back.
 






Gasket set-valve cover F77Z6584AE

Does this include a pair of valve cover gaskets or is it just one? This project is getting expensive fast.

Thanks.
 






valve covers

Gasket set-valve cover F77Z6584AE

Does this include a pair of valve cover gaskets or is it just one? This project is getting expensive fast.

Thanks.

I believe the set includes one for each bank. I reused by valve cover gaskets and had no problems.
 












traction side?

what side do you call the traction side of the chain

The slack side is the chain side that has the hydraulic/spring tensioner. It takes up the slack. The traction side is the left (driver) side for both front and rear. The jackshaft sprockets pull the camshaft sprockets via the chains.
 






thank you your info was exactly what i needed

The following list identifies the requirements to achieve accurate camshaft timing after all timing chain components and camshafts are installed on the engine.

1. The crankshaft must be locked in position (rotational motion in either direction prevented) with the #1 piston (right front of engine) at top dead center (TDC) on the compression stroke (intake and exhaust valves closed).

2. The jackshaft front and rear sprocket bolts must be tightened to the specified torque.

3.a. The right camshaft must be locked in position with the camshaft lobes for cylinder #1 not depressing the valves and the timing notch at the front of the camshaft below the camshaft centeline and parallel to the head surface that mates to the valve cover.

3.b. The traction side of the right timing chain must be taught (in tension).

3.c. The right camshaft sprocket bolt is torqued (tightens counter-clockwise) to 63 ft-lb (85 Nm)

4.a. The left camshaft must be locked in position with the camshaft position sensor protrusion above the camshaft centerline and the timing notch at the rear of the camshaft below the camshaft centeline and parallel to the head surface that mates to the valve cover.

4.b. The traction side of the left timing chain must be taught (in tension).

4.c. The left camshaft sprocket bolt is torqued (tightens clockwise) to 63 ft-lb (85 Nm)

Comments:

Some members have implemented creative methods to time their camshafts without purchasing the special timing kit OTC-6488. Unless a method to keep the chain taught when tightening the camshaft sprocket bolt is implemented the timing will not be accurate. The spring pressure provided by the normal spring/hydraulic tensioner is inadequate to tension the chain for timing. A bolt, washer and nut may be a suitable alternative for Timing Chain Tensioner Tool 303-571 (T97T-6K254-A) that is included with the timing kit.

Notes:

The camshaft sprocket bolts are not torque to yield and may be reused.

The jackshaft front and rear sprocket bolts are torque to yield and may not be reused.

The crankshaft damper bolt is a torque to yield and may not be reused.

The following tasks require separation of the engine and transmission. Accessibility to accomplish the task is significantly improved by pulling the engine rather than the transmission.
1. Rear timing chain replacement (requires flywheel/flexplate removal)
2. Rear timing chain guide assembly replacement
3. Jackshaft removal (requires flywheel/flexplate removal)
4. Jackshaft rear sprocket replacement (requires flywheel/flexplate removal)

Related Ford part numbers:

Jackshaft/primary timing chain kit 2U3Z6D256CA includes:
Crankshaft bolt harmonic balancer E7RY6A340B
Tensioner-engine jackshaft chain YL2Z6L266AA
Gasket-cylinder/timing front cover F77Z6020AB
Sprocket/gear-engine jackshaft/intermediate 2U3Z6M264AA
Guide-engine jackshaft chain 2L2Z6K297AA
Bolt-jackshaft sprocket bolt F77Z6M264BA superseded by 2L2Z6279AA (included when 2U3Z6M264AA is purchased)
Sprocket/gear-crankshaft two wheel drive 2L2Z6306BA
Chain-engine jackshaft F77Z6268AB
Bolt-camshaft sprocket right hand
Bolt-camshaft sprocket left hand F77Z6279BA

Left/front timing chain cassette assembly 7U3Z6A257A includes:
Timing chain
Guide assembly YL2Z6M273AA superseded by 7U3Z6A257A
Bolt-guide assembly upper mount
Sprocket/gear-camshaft
Sprocket/gear-jackshaft front

Right/rear timing chain cassette assembly 4L2Z6M290AA includes:
Timing chain
Guide assembly
Sprocket/gear-camshaft
Sprocket/gear-jackshaft rear

00M12 intake manifold kit YL2Z9E473AA includes:
Lower intake manifold gasket set of six YL2Z9461AA
Upper intake manifold gasket set of two YL2Z9E436AA
Left timing chain tensioner 7U3Z6K254B
Tensioner metal O ring XU2Z6M252AA
Oil restrictor
Galley plug

Right timing chain tensioner 7U3Z6K254A supersedes XU3Z6K254BA

Right timing chain guide assembly upper postioning bolt F77Z6U000BA

Jackshaft rear sprocket retaining bolt W703167S430

Cover assy/rear of block jackshaft opening plug F77Z6026AB

Left cassette assembly lower mounting bolt W500100S300

Jackshaft chain guide mounting bolt W500100S300

Sprocket/gear-crankshaft inner four wheel drive F77Z6306BE

Sprocket/gear - crankshaft outer four wheel drive 2L2Z6306AA

Balance shaft chain guide F77Z6K297BC

Balance shaft chain tensioner 1L2Z6L266AA

Balance shaft chain F77Z6268BC

Balance shaft assembly 1L2Z6A311AA

Seal-front timing cover E6TZ6700A was superseded by 5H2Z6700AA

Gasket set-valve cover F77Z6584AE

Gasket-lower oil pan 4L2Z6710AA year 2000+ F77Z6710BA year 1997-1999

Gasket-upper oil pan/reinforcement section F77Z6710AA

Left camshaft F7TZ6250AEE was superseded by 7L2Z6250D

Right camshaft F77Z6250AE

Exhaust manifold outlet bolts (M12-1.75X54.5 H) N811747S2
 






I read a link on here where USAsomething or another was selling cloyes timing chain set ups for 4.0 Sohc engines on ebay for around 150.00. I can't navigate back to the thread. It was as good as OEM and guys were impressed with it. Anyone know the thread there was a link I searched ebay and didn't see it.

Any one want to rent their 488 timing chain tool kit? I want to rent it for $75.00 and leave a $150 deposit up front. I've seen a couple for sale on the Explorer forum for a 150.00 so 150 deposit is no harm no foul I'll pay shipping both ways. Trying to budget this rebuild under $800. It's an extra engine 2001 Plus I have a 2002 SOHC low milage I'm installing in the 2001 Sport that the other engine came out of. The 02 e motor is low milage but while it's on my engine table I'm 50/50 on replacing the chains. I scour Craigs list looking for down explorers I like the ones needing transmission but there is so many needing SOHC engines more specific timing chains really inexpensive buys. This is my first SOHC I might as well learn the timing chain waltz. Thanks Stefin
 



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Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
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I read a link on here where USAsomething or another was selling cloyes timing chain set ups for 4.0 Sohc engines on ebay for around 150.00. I can't navigate back to the thread. It was as good as OEM and guys were impressed with it. Anyone know the thread there was a link I searched ebay and didn't see it.

Any one want to rent their 488 timing chain tool kit? I want to rent it for $75.00 and leave a $150 deposit up front. I've seen a couple for sale on the Explorer forum for a 150.00 so 150 deposit is no harm no foul I'll pay shipping both ways. Trying to budget this rebuild under $800. It's an extra engine 2001 Plus I have a 2002 SOHC low milage I'm installing in the 2001 Sport that the other engine came out of. The 02 e motor is low milage but while it's on my engine table I'm 50/50 on replacing the chains. I scour Craigs list looking for down explorers I like the ones needing transmission but there is so many needing SOHC engines more specific timing chains really inexpensive buys. This is my first SOHC I might as well learn the timing chain waltz. Thanks Stefin
 






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