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X180 2.2 NA Timing Belt Service Notes Please - Engine/Ancilliaries - The Lotus Forums Jump to content
Gee21

X180 2.2 NA Timing Belt Service Notes Please

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Hi,

My trusted mechanic is doing my timing belt at the weekend. He's never done one on these engines before and I just wondered if anyone had a document or a copy of the service notes that I could have. He just wants to make sure we have all information before doing it. 

Many thanks in advance.

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There are several posts about changing the timing belt and presumably this will be attempted with the engine in place.

Access and visibility are the issues if the engine is not removed. The method of splicing the existing timing belt in half length-ways with the crank pulley removed and the tension bearing released has been done by some, but I've never tried it myself. There is a hard to see (depending on how clean you engine is) Allen key bolts holding the tension for the auxiliary belt (water pump I believe) that you will need to release to remove the outer belts (your alternator and AC belt if fitted are more obvious).

Getting the tension right on the new belt is very important so as your mechanic will be working almost blind, make sure he notes the orientation of the tension bearing should he need to remove/replace.

Good luck, and if he does a good job be sure and provide his details on the forum.         

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Thanks and yes I have found a very good step by step method after half an hour of searching.

My guy is very good. We spent 12 hours on the car on Saturday replacing the exhaust manifold, front and rear brakes, full service, brake fluid change, headlight repair to both pods and repaired the choke cable. All went well. He had the manifold done in 4.5 hours with the engine in situ which I think may be a record. :-) Its driving a lot better now. The old one was totally knackered with holes and cracks all over it. 

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That shirt washed up quite nicely.

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I bet you couldn't shift that oil from under your nails though! 

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Anyone whom can get a manifold off in situ frankly must have the patience of a saint and god like qualities 

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Bless you.

  • Haha 2

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19 hours ago, Barrykearley said:

Anyone whom can get a manifold off in situ frankly must have the patience of a saint and god like qualities 

Finally!  Someone who recognizes my talents. :lol:

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On 3/5/2018 at 02:54, Gee21 said:

Hi,

My trusted mechanic is doing my timing belt at the weekend. He's never done one on these engines before and I just wondered if anyone had a document or a copy of the service notes that I could have. He just wants to make sure we have all information before doing it. 

Many thanks in advance.

Damien, Here it is:

 

9XX  Timing Belt Removal & Replacement 

The Tim Engle's timing belt doc from the Yahoo group Turbo Esprit.

Timing Belt - Remove & Replace Procedure.doc (126.5 KB, 193 views)

When  working from the topside of the engine, do NOT brace yourself against, or lay upon the intake manifold or the plenum/ air box.

If you do,  at a minimum,  you may flex a joint and create an air leak that will drive you nuts trying to diagnose later.

Worst case,  the fuel injection intake manifolds (later Esprits) are known to crack.   Replacements are out of production/ out of inventory,  and if you do find a used one,  they are very expensive.

Esprit owners could pull the engine,  but that's a ton more work.   If you have to ask how to replace the timing belt,  then you’re not prepared for removing and replacing the engine and transmission.   If you read this document, and replacing the belt with the engine in the car begins to sound to you like a lot of work,  then brace yourself, because removing and replacing the engine is going to be more work.   I recommend doing the job with the engine in place.

 

Bolts & bits you remove should be put in plastic bags, which are then marked with from where the contents came.   Take lots of before photos... with a digital camera, you can't take too many.   Never trust your memory.

 

Planning Ahead – Auxiliary Pulley Timing

For engines equipped with distributors, the auxiliary pulley’s position is critical to ignition timing.   Change how the pulley is indexed on the timing belt, and you change the ignition timing.   For later 910’s with crank triggered ignition, this is a non-issue… skip over this section.

The Auxiliary pulley has a timing dot on its rim that’s used for indexing the auxiliary pulley (in addition to the dots used for timing the cams).   The standard procedure is for that dot to be facing forward, and the pulley turned so the dot is at about the five o’clock position and lies on the centerline between the Auxiliary Shaft and the Crankshaft.   Given the distance between those two shafts, and the other bits between them,  it can be difficult to accurately index the Aux pulley.   In an Esprit,  working between the engine and the firewall,  the degree of difficulty goes up another notch.

DORMAN Pan  264431

The following alternative method requires that you place some paint marks on the Intake Cam Pulley and Auxiliary Pulley before starting to dismantle things.   The downside is that later it will only replicate the current setting.   If the timing is off now,  it will be off later when you get it all back together.   Check the ignition timing before starting.   If you like where it is, then proceed with the following.   If the timing is wrong now by more than can be adjusted at the distributor (i.e., the pulley needs to be indexed on the belt),  then it’s best that you abandon this method before you start,  and plan on following the book method later.

Set the crank to TDC with the cam pulley timing dots properly aligned and on the centerline between the cams.   Then put a paint mark on one of the teeth on the intake cam pulley where it’s easily visible.   On the mid-engine Esprit,  that’s on the back side,  toward the top of the pulley.   Do the same on the aux pulley.   It's not important which two teeth,  just as long as each is in the area where the belt is in full contact with the pulley and not lifting away from the tangent point.   I choose teeth as close together as possible while still in full contact with the pulley.

Now, count the number of belt teeth between the intake paint mark to the auxiliary paint mark, and write it down the number where you won't lose it.   It's good to take a digital photo of the paint marks for future reference, and write on a print.

*~*~*~*

Caution, most cleaners/ degreasers will quickly remove a paint mark.   If you're going to clean the pulleys,  then don't wipe off your paint marks,  or the factory painted timing dimples.

*~*~*~*

Later,  when you install the timing belt,  confirm the crank is at TDC and get the belt started on the Int &Exh cam pulleys with the dots aligned on the centerline.   Then, count belt teeth from your paint mark on the Intake cam over to the painted tooth on the aux pulley,  and slip the belt onto the pulley in that position.

Dis-Assembly:

On Esprit Turbos,  remove the fiberglass under tray from the bottom of the engine bay.

 

Working from the top side,  remove the thermostat housing and the hose that runs across the top-front of the engine bay above the alternator.

 

Disconnect the battery (+) cable.   Remove the alternator and its triangular support bracket.   Earlier engines, like the 907, don’t have the triangle bracket,  but all 910 Turbo engines do.   The V-belt definitely has to go,  but removing the alternator itself is just a matter of making work room.   Removing and replacing it don’t take long,  and subsequent steps are easier with it gone.

 

In the Bosch fuel injected 910 models,  remove the black plastic fuel injection hoses that run across the front of the engine bay.   That’s optional to a degree,  but they are really in the way and vulnerable to damage.   It takes less time to remove them than it does to talk you into doing it.

 

The Bosch fuel lines are pressurized to 95 psi and the accumulator bleeds down slowly after the engine is switched off,  so presume the lines are fully pressurized.   Wrap a rag around a fitting while you slowly crack it loose.   Allow the pressure to vent slowly before just spinning the bolt out.   Each banjo bolt fitting has a small aluminum crush washer for sealing.   Be sure to pick them off as well.   Order replacement crush washers… avoid re-using the old ones.

 

Remove the V-belt from the vacuum and water pumps.   The vacuum pump tensioning bolts are difficult to access.   For them,  buy a regular "L" shaped Allen wrench plus a GearWrench of the same size (Sears sells GearWrench brand).   I think it's 8mm for the adjuster... ??  Measure first.   Using a hacksaw,  cut off of a stub of Allen wrench about 5/8" to 3/4" long and stick it into the cap screw head, turning it into a male Allen drive.   Then put the GearWrench on the Allen stub.   That way you can access it from the side instead of head-on,  and the GearWrench's ratchet action avoids the need to re-position the wrench one flat at a time.

 

Sears usually stocks a variety of GearWrench styles in each size:  stubby,  regular,  long,  flex-head, etc.   Buy the longest one you can get.   Those cap screws are usually pretty darned tight,  and a standard 8mm wrench is too short to give you much leverage.   Buy a long one.

 

Loosen the A/C belt tensioner’s pinch bolt and pivot bolt.   Remove the V-belt.   That can be easier said than done.   It’s easier if the tensioner is completely removed.   Then pull the bottom run of belt forward,  hooking it on the outer edge of the compressor’s pulley.   Force it as far as you can.   A screw driver between the belt and pulley rim can be used as a lever.   When it won’t go any further,  put a 19mm (3/4”),  half inch drive ratchet on the crank pulley bolt,  and manually turn the engine over,  walking the belt off the AC pulley.

 

V-belts are cheap.   As long as you're going to remove them anyway,  plan to install new ones later.   In that case, removing the old ones goes much faster if you use a utility knife.   It's a good idea to have the new belts on hand before cutting the old ones.

 

Remove the V-belt pulley from the front of the crankshaft.   Have a helper put the transmission is 5th gear,  release the clutch  and stand on the brakes while you loosen the bolt.

 

Try to pull the pulley off by hand.   If it’s stuck,  try tapping it forward with a plastic or rubber mallet.   The pulley is aluminum,  so don’t go after it with a big steel hammer.   There’s some room to pry at it, but nothing really solid to pry against if real brute force is required.   Don’t go breaking other expensive bits.   Patience,  penetrating oil (Kroil is the best), and heat may be required.

 

If you do use heat,  be careful not to direct it behind the pulley where it may damage the front main seal.   For the same reason,  don’t get the overall mass too hot.   Use heat on the pulley only, and in moderation.

If the pulley is well and truly corroded onto the front of the crank,  this could be the nastiest part of the whole job.   Especially since most 9XX installations don’t have enough room in front of the engine to permit the use of a large 3-jaw puller.

Make a note for later…  always install the front crank pulleys,  both the V-belt pulley and the small toothed timing belt pulley,  with a liberal application of Anti-Seize.

On the up side,  more often than not,  the pulley comes off without much fuss.

 

Removing the Timing Belt:

If the belt is to be replaced with a new one,  then the simple expedient to removal is to cut it with a utility knife.   Same could be done with the V-belts.   However, it’s best to have the replacements on hand before cutting.

If the belt is to be re-installed,  then draw an arrow on it indicating it’s present direction of operation.   The cord body takes a set during use.   Once run in,  the belt’s direction of operation should never be changed.   If it is to be re-installed, then take pains to install it the same way it was before it was removed.   If you forget to do that,  then buy a new belt rather than gamble on getting it wrong.

 

Set the crank to TDC with the cam pulley timing dots adjacent and aligned on the centerline between the cams.   If the dots end up on far opposite sides of the cam pulleys,  then turn the crank through one more full revolution and back to TDC  (i.e., the cams turn as 1/2 revolution for each crank revolution).

 

Always turn the crank in its normal operating direction, clockwise.   Never go backwards.   There’s no direct timing risk related to going backwards, but there are a variety of secondary ills that can occur.   There are different ills for different iterations of the 9XX engine.   Rather than getting into each condition,  I’ll just say that always turning the crank in the normal operating direction is a safe habit to practice.

 

If the engine is equipped with an eccentric timing belt tensioner,  then loosen the pinch bolt (17mm offset ring wrench) and then turn the eccentric  (19mm offset ring erwnch), to the maximum loose position,  giving you the most belt slack possible with which to work (it’s still not much).

If the engine is equipped with the spring loaded, semi-automatic timing belt tensioner,  the piston must be retracted and pinned prior to removing the belt.

Back out the tension adjusting screw until there is approximately 12mm of exposed thread.   Don’t go too far or the threads will disengage and the internal springs will shoot it out.   Do not have your head down in the line of fire,  and good luck finding the adjuster later. There’s a 4mm hole in the front side of the tensioner, either above or below the piston bore.   A locking pin is inserted through the hole to engage a groove cut around the piston, locking the piston in place.   The hole’s location changed through the years.   It may be above or below the piston bore,  it may be exposed and to the right of the lower mounting bolt,  or it may be hidden under one of the mounting bolt washers.   If it’s under a washer,  more often than not it’s under the lower washer…  but not always. With the other bolt torqued tightly enough to hold the tensioner in position, remove the bolt and washer that hide the locking pin hole.   Start a 4mm pin in the hole (I use a snug fit drill bit shank),  wiggling it along with an inward pressure.   Place one hand on the timing belt mid-way between the intake and auxiliary pulley and push down firmly.   The additional pressure on the belt will retract the tensioner’s piston into the bore.   When the piston’s groove aligns with the hole,  the pin should drop in… with some effort and wiggling.   Make certain the pin is fully engaged, then release the hand pressure on the timing belt.

        

In either case,  with the timing belt now fully slack,  slide it forward off the two cam pulleys,  the auxiliary pulley,  the tensioner  and the crankshaft sprocket.

 

If the task at hand is to simply install a new timing belt,  then start that now.   However,  if there is other work to be done,  then there’s some risk of the crank inadvertently being rotated enough to bring a piston into contact with some valves and possibly bending the valves.   The safe thing to do is to turn the crank back to 90 BTDC.   That puts all the pistons half way down their bores and well away from the valves.

 

Tasks to be considered at this point are:

1)  Rebuild the Water Pump, or at least, install Allen cap head stainless bolts.

2)  Replace the front main seal.

3)  Replace the cam seals

4)  Replace the Auxiliary shaft seal.

5)  Check the valve clearances, and shim the valves if required.

6)  Replace the tensioner bearing.

7)  Rebuild the semi-automatic tensioner (G-cars)

8)  Re-set the “emissions’ cam timing to the design timing, installing new cam pulleys as required.

 

Install the Timing Belt:

The small toothed sprocket on the crankshaft has a cupped flange washer behind it.  Check the sprocket for cracks; remove, wash, examine (often cracks trough the threaded hole area).  A raised boss on the back face of the sprocket telescopes through the washer,  then the sprocket pinches the washer back against a step on the crankshaft.   If the sprocket has been disturbed or removed,  then it’s common for the washer to slip off the sprocket’s raised boss,  and drop down behind it.   Make certain the washer is properly seated.  If the old timing belt is not being removed,  and the bolt securing the front V-belt pulley was never loosened,  then the washer has not been free to move.

The above washer is cupped rather than flat.   As it extends out beyond the sprocket’s OD,  it also curves back away from the sprocket,  forming a funnel-guide for the timing belt.   If the washer curves forward over the sprocket,  then it’s on backwards.   Remove the sprocket and re-position the washer.

 

If the crank sprocket needs to be removed,  it can usually be pried off using two screw drivers,  one per side prying simultaneously.   If it’s really stuck,  there are two M5 tapped  holes  in the front face that accept bolts from a small puller (ie, steering wheel hub puller).

Both the crank sprocket and the V-belt pulley should be installed with Anti-Seize applied to their bores, keys and the crank journals.

Double check that the crank is at TDC,  and that the timing dots on the cam pulleys are adjacent to one another,  and aligned on the centerline between the cams.   If they are aligned,  but above or below the centerline,  they are still not properly timed.   The dots must be  BOTH  aligned  and  on the centerline. Make sure that the pointer (visible in the clutch inspection window), is at the TDC mark on the rim of the fly wheel.

 

Slip the timing belt onto the small toothed sprocket on the crankshaft.   Route the belt up over the tensioner pulley,  and generally lay the belt up into position near the upper pulleys.

 

Grasp the belt with both hands,  one on either side of the crank sprocket.   Pull upward firmly on the strands to either side of the crank, wiggling back and forth a bit as necessary to fully seat the belt teeth on the crank sprocket.   Fish the slack-side strand up around the tensioner pulley and toward the auxiliary pulley.   Don't put it on the auxiliary pulley yet, just have it staged there.

 

Pull the tension-side of the belt up snug toward the exhaust cam pulley.   Murphy's Law probably won't allow the belt and pulley teeth to mesh perfectly,  but don't pull the belt testosterone-tight when going for a mesh.   You cannot stretch the belt (!),  and too much force will only rotate the crank...  then you'll have to go back and start over.

 

Instead,  pull the belt up taut toward the exhaust cam pulley,  put a 17mm wrench on the bolt that retains the cam pulley,  and turn the pulley minimally as required for a perfect mesh.   Slide the belt back onto the pulley only about 3/8" to 1/2"of its width… just enough to be secure.   Use the wrench to turn the pulley back in the tension direction just enough to pull slack out of the belt, but don't try to tension it (pull too hard and you'll turn the crank, and/or loosen the pulley bolt).

 

Note:   The belt is very stiff side to side (in the flat plane).   If it is slid all the way back onto one pulley,  it will be too stiff to zig-zag back out to start on the forward face of the next pulley.   Barely start the back edge of the belt on all three upper pulleys (two cam pulleys and the auxiliary pulley) before sliding it back to fully engage them.

Pull the belt taut over to the intake pulley.   Again, use the wrench to turn the intake pulley as required to meet the belt,  and slide the belt 3/8" to 1/2" onto the pulley.   Turn the pulley back in the tension direction just enough to pull slack out of the belt.

 

Check the cam timing dots for any obvious mis-alignment at this point... the crank must be at TDC and the pulley dots aligned ON the centerline.   Correct any error before proceeding over to the aux pulley.

 

Engines with crank-triggered ignition (910S, Esprit SE thru S4s) don’t have to worry about the Aux pulley’s position,  but engines with distributors do.   Turn the Aux pulley to align the dot on the rim with the centerline between the Aux shaft and crankshaft, as noted in the manual,  and as an addendum below.   Or, if you made your own paint dots as suggested at the beginning,  now is the time to count belt teeth from the Intake pulley paint mark to the Aux pulley paint mark.   Know which teeth you need to mesh before starting your struggle with the belt.

 

With the timing belt on the cam pulleys on one side,  and over the tensioner roller on the other side,  pull all the slack from both sides of the crank pulley up and around toward the Auxiliary pulley.

 

It can be difficult to fit the belt on the last pulley (Auxiliary pulley).   The belt is nearly a net fit on the pulley circuit, and there's no excess slack to make it easy to slide it onto the last pulley.   Make sure the tensioner is fully backed off so you have the entire possible belt slack available.   A used belt will have stretched a bit during prior use and will be easier to install;  but a new, un-stretched belt can be pretty snug.   HTD belts are thicker and stiffer than trapezoidal belts, and will fight you more.

 

If the belt just will not go on the Aux pulley despite your best effort,  then try this.   Position yourself behind the pulleys,  reaching forward to handle the belt.   Start the belt onto the Aux pulley from the side facing the intake cam,  and barely hooking it over the edge of the pulley.   Work it on as far around the pulley as you can before it just won't go any more.

Hold the belt there with your left hand.   Then, working from behind the pulley,  lay the fingers of your right hand across the top of the pulley and belt,  catching the far, forward edge of the belt with your first knuckle joint.   Force the edge of the belt down, laying it flat over the front face of the pulley.   "On-edge",  the belt is stiff,  and you can pull it back up, sliding it along the face of the pulley until it's edge "just" clears the rim the rest of the way around.   Then rotate the belt back up to horizontal while simultaneously pulling it back onto the pulley.   With a little practice,  you can make that one fluid motion.   Doing it is not as difficult as deciphering what I just wrote.

 

Now that the belt is started onto all the pulleys,  you can slide it back fully onto all three pulleys.

Adjust the tensioner to put some heavy tension on the belt,  but don’t worry about an exact amount for now.   In the case of the spring loaded, semi-automatic tensioner,  that means remove the locking pin,  re-install the second mounting bolt and tighten them both,  and screw the adjuster inward. When the tensioner pulls the slack out of the belt,  sometimes the pulleys move. 

 

Normally,  if you kept all the slack out of the system while installing the belt,  the pulleys won’t move enough to get out of time.   But don't get bummed if the first fitting requires a re-do... it happens.   What must not happen is to let it go un-corrected.

 

Double check that the crank is still at TDC,  the cam pulley timing dots are aligned on the centerline, flywheel pointer at TDC and count the number of teeth between the painted teeth on the two pulleys (if you’re using that method).   If everything is not perfect,  then note which way any pulley has to be moved on the belt,  and repeat the process as necessary to get everything installed correctly.   Don’t worry about small, partial tooth misalignments, since you can only index the pulley on the belt by whole tooth increments.   Get the timing correct under some tension before worrying about setting the tension to spec.

 

The manual shows an extra dot on the pulley rim that's used for setting the Aux pulley (see the NA Workshop Manual, Section E – Engine, Page 19,  or the Turbo Service Notes, Sect EB, page 10).   That works okay on an engine stand where you have a good view of the front of the engine,  but it's not as convenient when you're working between the engine and the firewall.

That dot/centerline set-up works for the Euro version of the engine.  However, the federal engine uses a different ignition timing that often results in the vacuum diaphragm capsule striking either the oil filter or the intake manifold before achieving the spec static timing.

 

In that case, the aux pulley needs to be timed with the dot a couple of teeth off the center line; however Lotus didn't re-draw the illustration for the Federal engine.   If you wish to use the dot/center line method,  check (better yet, PHOTOGRAPH) the relationship at TDC before taking everything apart.

 

Note:   One tooth pitch on the pulley  =  9° degrees of cam timing (360 divided by 40 teeth on the pulley), = 18° of crank timing

All cam timing is done with the crankshaft set to TDC.   Imagine it's welded there.   You can't create a scenario or excuse to justify moving the crank off TDC !!

With the crank at TDC,  the cam pulley timing dots must align on the imaginary center line between the cams/ pulleys and flywheel pointer has to be on TDC mark.   If the dots align, but they're both above or below the center line by a whole tooth increment,  then the cams are still not properly timed.   The dots must be on the center line.   Index both pulleys on the timing belt as required to get their respective dots on the center line.

Having said that,  the world isn't always perfect.

On a single pulley,  from the tooth with the dot,  look to the next tooth over and imagine another dot in the same place on that tooth. That's a whole tooth pitch increment...  a gap plus a tooth width. From any point on one tooth to the exact same point on the next adjacent tooth is one whole tooth pitch.   You can only move the pulley on the belt in whole tooth pitch increments...  there's no way with stock parts to adjust for less error than that.

It's common for the dot/tooth alignment to be less than perfect. Anything that affects the dimension between the crank and cam center lines will cause small variances in dot/tooth alignment. Things like production tolerances, milling the head for flatness, decking the block,  etc,  will result in extra belt slack.   When the tensioner pulls that extra slack up over the cam pulleys to the tensioner side of the engine,  it will rotate both pulleys a little in the process...  retarding both cams a little.

If the crank is at TDC,  and the dots & teeth are very nearly aligned,  but off by less than a whole tooth pitch,  then there is no adjustment possible with stock parts that will bring them into perfection.   You could fix it with aftermarket adjustable vernier pulleys, but that's a completely different discussion.

 1)  With the crank at TDC (!!),  are the pulley timing dots aligned on the center line between the pulleys?   ALWAYS  EVALUATE  TIMING DOT  ALIGNMENT  WITH  THE  BELT  TENSIONED.   It doesn't have to be the "correct" tension,  but have some tension... ie, a healthy dose of tension sufficient to pull all existing belt slack over to the tensioner side of the engine... in the belt before checking the timing dot alignment.

2)  If they're off,  then are they off by a whole tooth pitch?   Not just off by some fraction of a pitch.   Not just off by a tooth FACE width...  but a whole tooth pitch (i.e.,  will indexing the pulley one tooth on the belt solve the problem?)

...a) If the dots ARE off by a whole tooth pitch (gap+tooth width),  slacken the tensioner making sure the belt is fully seated, partially remove/lift the timing belt at the offending pulley and index the pulley on the belt as required to get the timing dot aligned on the imaginary centerline. I t is handy tying belt to the “good” pulley with cable wrap to prevent slipping off.

...b) If the dots are off, but only by a small amount (a fraction of a whole tooth pitch),  then there's nothing you can do about it short of installing aftermarket adjustable cam pulleys. That small amount of error is not optimal to a perfectionist, but it will not cause a major problem in the engine's operation. It will not cause a 20 point drop in compression pressure.
If one or both pulleys is off the imaginary centerline by a whole tooth pitch,  then that could result in low cylinder pressure.
If a pulley is off by one tooth pitch,  that's not enough to cause the valves and pistons to collide.   Being off by two tooth pitches could be a bent valve problem...  you're getting really close.

 

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